(68K) Serial Manager | Palm OS® Programmer's API Reference

This chapter provides reference material for the Serial Manager API:

The header file SerialMgr.h declares the Serial Manager API. The file SystemResources.h defines some serial port constants. For more information on the Serial Manager, see the chapter "Serial Communication" of the Palm OS Programmer's Companion, vol. II, Communications.

Serial Manager Data Structures ^TOP^

DeviceInfoType Struct ^TOP^

Purpose

The DeviceInfoType structure defines information about a serial device. This structure is returned by the SrmGetDeviceInfo() function.

Prototype

typedef struct DeviceInfoType {
  UInt32 serDevCreator; 
  UInt32 serDevFtrInfo; 
  UInt32 serDevMaxBaudRate; 
  UInt32 serDevHandshakeBaud; 
  Char *serDevPortInfoStr; 
  UInt8 reserved[8];
} DeviceInfoType;

typedef DeviceInfoType *DeviceInfoPtr;

Fields

serDevCreator: Four-character creator ID for serial driver.
serDevFtrInfo: Flags defining features of this serial hardware. See Serial Capabilities Constants for a description of these flags.
serDevMaxBaudRate: Maximum baud rate for this device.
serDevHandshakeBaud: Hardware handshaking is recommended for baud rates over this rate.
serDevPortInfoStr: Description of serial hardware device or virtual device.

SrmCtlEnum Enum ^TOP^

Purpose

The SrmCtlEnum enumerated type specifies a serial control operation. Specify one of these enumerated types for the op parameter to the SrmControl() call.

Prototype

typedef enum SrmCtlEnum {
  srmCtlFirstReserved = 0,
  srmCtlSetBaudRate, 
  srmCtlGetBaudRate, 
  srmCtlSetFlags, 
  srmCtlGetFlags, 
  srmCtlSetCtsTimeout, 
  srmCtlGetCtsTimeout, 
  srmCtlStartBreak, 
  srmCtlStopBreak, 
  srmCtlStartLocalLoopback, 
  srmCtlStopLocalLoopback, 
  srmCtlIrDAEnable, 
  srmCtlIrDADisable, 
  srmCtlRxEnable, 
  srmCtlRxDisable, 
  srmCtlEmuSetBlockingHook, 
  srmCtlUserDef, 
  srmCtlGetOptimalTransmitSize, 
  srmCtlSetDTRAsserted,
  srmCtlGetDTRAsserted,
  srmCtlSetYieldPortCallback,
  srmCtlSetYieldPortRefCon,
  srmCtlSystemReserved = 0x7000
  srmCtlCustom = 0x8000,
  srmCtlLAST
} SrmCtlEnum;

Constants

srmCtlSetBaudRate: Sets the current baud rate for the serial hardware.
srmCtlGetBaudRate: Gets the current baud rate for the serial hardware.
srmCtlSetFlags: Sets the current flag settings for the serial hardware. Specify flags from the set described in Serial Settings Constants.
srmCtlGetFlags: Gets the current flag settings for the serial hardware.
srmCtlSetCtsTimeout: Sets the current CTS timeout value for hardware handshaking.
srmCtlGetCtsTimeout: Gets the current CTS timeout value for hardware handshaking.
srmCtlStartBreak: Turn RS-232 break signal on. Caller is responsible for turning this signal on and off and insuring it is on long enough to generate a viable break.
srmCtlStopBreak: Turn RS-232 break signal off.
srmCtlStartLocalLoopback: Start local loopback test.
srmCtlStopLocalLoopback: Stop local loopback test.
srmCtlIrDAEnable: Enable IrDA connection on this serial port.

NOTE: You cannot enable an IrDA connection on a VZ processor.

srmCtlIrDADisable: Disable IrDA connection on this serial port.
srmCtlRxEnable: Enable receiver (for IrDA).
srmCtlRxDisable: Disable receiver (for IrDA).
srmCtlEmuSetBlockingHook: Set a blocking hook routine for emulation mode only. Not supported on the actual device.
srmCtlUserDef: This is a user-defined function that third-party hardware developers can use to set or retrieve hardware-specific information from the serial driver. This op code invokes the driver's corresponding control function with its user-defined op code and the parameters are passed directly through to the serial driver. A serial driver that does not handle this function returns a serErrBadParam error.; The srmCtlUserDef op code is superseded by defining a custom op code if New Serial Manager Feature Set Version 2 is present.
srmCtlGetOptimalTransmitSize: Ask the port for the most efficient buffer size for transmitting data packets. This op code returns an error (buffering not necessary), 0 (buffering requested, but application can choose buffer size), or a number greater than 0 (recommended buffer size).
srmCtlSetDTRAsserted: Enabled or disable the DTR signal. This is not supported by all hardware.
srmCtlGetDTRAsserted: Ask the port whether the DTR signal is enabled or disabled.
srmCtlSetYieldPortCallback: Set the function to be called if the Serial Manager attempts to open another port when this one is open. This op code is for system use only.
srmCtlSetYieldPortRefCon: Data to pass to the yield port callback function. System use only.
srmCtlSystemReserved: Reserves op codes between 0x7000 and 0x8000 for system use.
srmCtlCustom: Reserves op codes greater than 0x8000 for driver-specific use.

Compatibility

Custom control op codes are only supported if both New Serial Manager Feature Set Version 2 and 4.0 New Feature Set are present.

SrmOpenConfigType Struct ^TOP^

Purpose

The SrmOpenConfigType structure specifies parameters for opening a serial port. This structure is passed as a parameter to SrmExtOpen().

Prototype

typedef struct SrmOpenConfigType {
  UInt32 baud;
  UInt32 function;
  MemPtr drvrDataP;
  UInt16 drvrDataSize;
  UInt32 sysReserved1;
  UInt32 sysReserved2; 
} SrmOpenConfigType;

Fields

baud: Baud rate at which to open the connection. Serial drivers that do not require baud rates ignore this field.
function: The reason why the port was opened. Specify the creator ID of the application that is opening the port or one of the following values:; The function field is used by protocols such as USB and Bluetooth that perform different setup tasks based on which type of application is using them. RS-232 drivers ignore this parameter.
drvrDataP: Pointer to a driver-specific data block.
drvrDataSize: The size of the data block pointed to by drvrDataP.
sysReserved1: Reserved for future use.
sysReserved2: Reserved for future use.

Compatibility

This structure is only defined if both New Serial Manager Feature Set Version 2 and 4.0 New Feature Set are present.

Serial Manager Constants ^TOP^

Port Constants ^TOP^

When you specify the port to open in the SrmOpen(), SrmOpenBackground(), SrmExtOpen(), or SrmExtOpenBackground() call, you can use either a logical port constant, physical port constant, or a virtual port constant, but it is highly recommended that you use a logical port constant wherever possible.

Logical Serial Port Constants

These constants specify the logical port names.

Constant	Value	Description
`serPortLocalHotSync`	0x8000	The physical HotSync port. The Serial Manager automatically detects whether this port is USB or RS-232.
`serPortCradlePort`	0x8000	Cradle port. The Serial Manager automatically detects whether this port is USB or RS-232. Most applications should specify this as the port.
`serPortIrPort`	0x8001	The IR port. This is a raw IrDA port with no protocol support.
`serPortConsolePort`	0x8002	The debug console port, either USB or RS-232. USB is preferred where both are available.
`serPortCradleRS232Port`	0x8003	Port for the RS-232 cradle. Specify this port if you want to ensure that your application uses RS-232 communications only.
`serPortCradleUSBPort`	0x8004	Port for the USB cradle. Specify this port if you want to ensure that your application uses USB communications only.

Compatibility

USB ports are only supported if New Serial Manager Feature Set Version 2 is present.

Physical Serial Port Constants

The physical port constants specify 4-character constants that reference the physical hardware of the device. Doing so is not recommended because the hardware they reference may not exist on a particular device.

Physical port	Value	Description
`sysFileCUart328`	'u328'	Cradle port using the 68328 UART. This port can be switched between RS232 and IrDA mode using the `SrmControl()` call.
`sysFileCUart328EZ`	'u8EZ'	Cradle port using the 68328EZ UART. This port can also be switched between RS232 and IrDA mode.
`sysFileCUart650`	'u650'	Specifies the IR port on the upgrade card for Palm Personal or Palm Professional devices. This gives you a raw IR port like calling `SrmControl` does, but it only exists on devices that have the upgrade card.

Virtual Serial Port Constants

The virtual port constants specify 4-character constants that identify virtual ports, simulating a hardware interface. Virtual ports are not tied to specific hardware.

Physical port	Value	Description
`sysFileCVirtIrComm`	'ircm'	A virtual serial cable over an IrDA link using the IRComm protocol. It can only be used to talk to another IRComm device.
`sysFileCVirtRfComm`	'rfcm'	RFCOMM (Bluetooth) virtual port plug-in.
`sysFileCBtConnectPanelHelper`	'btcp'	Bluetooth Connection Panel helper application.

Compatibility

All virtual port constants other than sysFileCVirtIrComm are only defined if both New Serial Manager Feature Set Version 2 and 4.0 New Feature Set are present, and if the 5.0 New Feature Set is not present.

Serial Capabilities Constants ^TOP^

The serial capabilities constant flags describe serial hardware capabilities. These flags are set in the serDevFtrInfo field of the DeviceInfoType structure.

Constant	Value	Description
`serDevCradlePort`	0x00000001	Serial hardware controls RS-232 serial from cradle connector of Palm device.
`serDevRS232Serial`	0x00000002	Serial hardware has RS-232 line drivers.
`serDevIRDACapable`	0x00000004	Serial hardware has IR line drivers and generates IrDA mode serial signals.
`serDevModemPort`	0x00000008	Serial hardware drives modem connection.
`serDevCncMgrVisible`	0x00000010	Serial device port name string is to be displayed in the Connection panel.
`serDevConsolePort`	0x00000020	Serial device is the default console port.
`serDevUSBCapable`	0x00000040	Serial hardware controls USB serial from cradle connector of Palm device.

Compatibility

USB ports are only supported if New Serial Manager Feature Set Version 2 is present.

Serial Settings Constants ^TOP^

The serial settings constants identify bit flags that correspond to various serial hardware settings. Use SrmControl() with the op code srmCtlSetFlags to control which settings are used.

Constant	Value	Description
`srmSettingsFlagStopBitsM`	0x00000001	Mask for stop bits field
`srmSettingsFlagStopBits1`	0x00000000	1 stop bit (default)
`srmSettingsFlagStopBits2`	0x00000001	2 stop bits
`srmSettingsFlagParityOnM`	0x00000002	Mask for parity on
`srmSettingsFlagParityEvenM`	0x00000004	Mask for parity even
`srmSettingsFlagXonXoffM`	0x00000008	Mask for Xon/Xoff flow control (not implemented)
`srmSettingsFlagRTSAutoM`	0x00000010	Mask for RTS receive flow control. This is the default.
`srmSettingsFlagCTSAutoM`	0x00000020	Mask for CTS transmit flow control
`srmSettingsFlagBitsPerCharM`	0x000000C0	Mask for bits per character
`srmSettingsFlagBitsPerChar5`	0x00000000	5 bits per character
`srmSettingsFlagBitsPerChar6`	0x00000040	6 bits per character
`srmSettingsFlagBitsPerChar7`	0x00000080	7 bits per character
`srmSettingsFlagBitsPerChar8`	0x000000C0	8 bits per character (default)
`srmSettingsFlagFlowControlIn`	0x00000100	Protect the receive buffer from software overruns. When this flag and `srmSettingsFlagRTSAutoM` are set, which is the default case, it causes the Serial Manager to assert RTS to prevent the transmitting device from continuing to send data when the receive buffer is full. Once the application receives data from the buffer, RTS is de-asserted to allow data reception to resume.
		Note that this feature effectively prevents software overrun line errors but may also cause CTS timeouts on the transmitting device if the RTS line is asserted longer than the defined CTS timeout value.
`srmSettingsFlagRTSInactive`	0x00000200	If this flag is set and `srmSettingsFlagRTSAutoM` is not set, RTS is held in the inactive (flow off) state forever.

Status Constants ^TOP^

The status constants identify bit flags that correspond to the status of serial signals. They can be returned by the SrmGetStatus() function.

Constant	Value	Description
`srmStatusCtsOn`	0x00000001	CTS line is active.
`srmStatusRtsOn`	0x00000002	RTS line is active.
`srmStatusDsrOn`	0x00000004	DSR line is active.
`srmStatusBreakSigOn`	0x00000008	Break signal is active.

Line Error Constants ^TOP^

The line error constants identify bit flags that correspond to the line errors that may occur on the port. They can be returned by the SrmGetStatus() function.

Constant	Value	Description
`serLineErrorParity`	0x0001	Parity error
`serLineErrorHWOverrun`	0x0002	Hardware overrun
`serLineErrorFraming`	0x0004	Framing error
`serLineErrorBreak`	0x0008	Break signal asserted
`serLineErrorHShake`	0x0010	Line handshake error
`serLineErrorSWOverrun`	0x0020	Software overrun
`serLineErrorCarrierLost`	0x0040	Carrier detect signal dropped

Serial Manager Functions ^TOP^

SrmClearErr Function ^TOP^

Purpose

Clears the port of any line errors.

Declared In

SerialMgr.h

Prototype

Err SrmClearErr (
   UInt16 portId
)

Parameters

→ portID: Port ID returned from SrmOpen() or SrmExtOpen().

Returns

This function returns the following error codes:

errNone: No error.
serErrNotSupported: The port is not the foreground port.

Compatibility

Implemented only if New Serial Manager Feature Set Version 1 is present.

SrmClose Function ^TOP^

Purpose

Closes a serial port and makes it available to other applications, regardless of whether the port is a foreground or background port.

Declared In

SerialMgr.h

Prototype

Err SrmClose (
   UInt16 portId
)

Parameters

→ portId: Port ID for port to be closed.

Returns

This function returns the following error codes:

errNone: No error.
serErrBadPort: This port doesn't exist.
serErrNotOpen: The serial port is not open.
serErrNoDevicesAvail: No serial devices could be found.

Comments

If a foreground port is being closed and a background port exists, the background will have access to the port as long as another foreground port is not opened.

If a foreground port is being closed and a yielded port exists, the yielded port will have access to the port as long as it does not yield to the opening of another foreground port. If there are both a yielded port and a background port for the foreground port being closed, the yielded port takes precedence over the background port.

Compatibility

Implemented only if New Serial Manager Feature Set Version 1 is present.

SrmControl Function ^TOP^

Purpose

Performs a serial control function.

Declared In

SerialMgr.h

Prototype

Err SrmControl (
   UInt16 portId,
   UInt16 op,
   void *valueP,
   UInt16 *valueLenP
)

Parameters

→ portID: Port ID returned from SrmOpen() or SrmExtOpen().
→ op: Control operation to perform. Specify one of the SrmCtlEnum enumerated types.
↔ valueP: Pointer to a value to use for the operation. See Comments for details.
↔ valueLenP: Pointer to the size of *valueP. See Comments for details.

Returns

This function returns the following error codes:

errNone: No error.
serErrBadParam: An invalid op code was specified.
serErrBadPort: This port doesn't exist.
serErrNotOpen: The serial port is not open.
serErrNoDevicesAvail: No serial devices could be found.
serErrNotSupported: The specified op code is not supported in the current configuration.

Comments

Table 70.1 shows what to pass for the valueP and valueLenP parameters for each of the operation codes. Control codes not listed do not use these parameters. See SrmCtlEnum for a complete list of control codes.

Table 70.1 SrmControl Parameters

Operation Code	Parameters
`srmCtlSetBaudRate`	`→ valueP = Pointer to Int32 (baud rate)` `→ valueLenP = Pointer to sizeof(Int32)`


`srmCtlGetBaudRate`	`← valueP = Pointer to Int32 (baud rate)` `← valueLenP = Pointer to Int16`


`srmCtlSetFlags`	`→ valueP = Pointer to Uint32 (bitfield; see Serial Settings Constants)` `→ valueLenP = Pointer to sizeof(UInt32)`


`srmCtlGetFlags`	`← valueP = Pointer to UInt32 (bitfield)` `← valueLenP = Pointer to Int16`


`srmCtlSetCtsTimeout`	`→ valueP = Pointer to Int32 (timeout value)` `→ valueLenP = Pointer to sizeof(Int32)`


`srmCtlGetCtsTimeout`	`← valueP = Pointer to Int32 (timeout value)` `← valueLenP = Pointer to Int16`


`srmCtlUserDef`	`↔ valueP = Pointer passed to the serial or virtual driver` `↔ valueLenP = Pointer to sizeof(Int32)` For a serial driver, these pointers are passed to the driver's control function and they contain that functions return values (if any) upon return.
`srmCtlGetOptimalTransmitSize`	`← valueP = Pointer to Int32` `← valueLenP = Pointer to sizeof(Int32)` If an error is returned by `SrmControl`, no buffering should be done. If `valueP` points to zero, buffering is requested, but the transmitting application cannot determine the buffer size. If `valueP` points to a number > 0, then try to send data in blocks of this number of bytes, as this is the most efficient block size for this particular device.
`srmCtlSetDTRAsserted`	`→ valueP = Pointer to Boolean indicating whether to enable or disable DTR.` `→ valueLenP = Pointer to sizeof(Boolean)`
`srmCtlGetDTRAsserted`	`← valueP = Pointer to Boolean indicating whether DTR is enabled.` `← valueLenP = Pointer to Int16`

Compatibility

Implemented only if New Serial Manager Feature Set Version 1 is present.

SrmCustomControl Function ^TOP^

Purpose

Performs a custom serial control function.

Declared In

SerialMgr.h

Prototype

Err SrmCustomControl (
   UInt16 portId,
   UInt16 opCode,
   UInt32 creator,
   void *valueP,
   UInt16 *valueLenP
)

Parameters

→ portID: Port ID returned from SrmOpen() or SrmExtOpen().
→ opCode: Control operation to perform. The op code must be greater than srmCtlCustom.
→ creator: Creator ID of the driver that defines the op code. The combination of creator ID and op code uniquely identifies the operation to be performed.
↔ valueP: Pointer to a value to use for the operation.
↔ valueLenP: Pointer to the size of *valueP.

Returns

This function returns the following error codes:

errNone: No error.
serErrNotSupported: The port is not the foreground port.
serErrBadPort: This port doesn't exist.
serErrNotOpen: The serial port is not open.
serErrNoDevicesAvail: No serial devices could be found.

Comments

This function is a mechanism for a virtual driver to create control codes specific to that driver, allowing for the support of new technologies that have interfaces through the Serial Manager.

This function simply forwards the opCode and any valueP parameter to the virtual driver for the port. The virtual driver may return its own error code if the opCode or the input in valueP is invalid.

Compatibility

Implemented only if both New Serial Manager Feature Set Version 2 and 4.0 New Feature Set are present.

SrmExtOpen Function ^TOP^

Purpose

Opens a foreground port connection with the specified configuration.

Declared In

SerialMgr.h

Prototype

Err SrmExtOpen (
   UInt32 port,
   SrmOpenConfigType *configP,
   UInt16 configSize,
   UInt16 *newPortIdP
)

Parameters

→ port: The four-character port name (such as 'ircm' or 'u328') or logical port number to be opened. (See Port Constants.)
→ configP: Pointer to the configuration structure specifying the serial port's properties. See SrmOpenConfigType.
→ configSize: The size of the configuration structure pointed to by configP.
← newPortIdP: Contains the port ID to be passed to other Serial Manager functions.

Returns

This function returns the following error codes:

errNone: No error.
serErrBadPort: The port parameter does not specify a valid port.
serErrBadParam: The configP parameter is NULL.
serErrAlreadyOpen: The Serial Manager already has a port open.
memErrNotEnoughSpace: There was not enough memory available to open the port.

Comments

Do not keep the port open any longer than necessary. An open serial port consumes more energy from the device's batteries.

The values specified in the configP parameter depend on the type of connection being made. For RS-232 connections, you specify the baud rate but not a purpose. For USB connections, you specify a purpose but not a baud rate.

A newly opened port has its line errors cleared, the default CTS timeout set (specified by the constant srmDefaultCTSTimeout), a 512-byte receive queue allocated, 1 stop bit, 8 bits per character, RTS enabled, and flow control enabled. To increase the receive queue size, use SrmSetReceiveBuffer(). To change the other serial port settings, use SrmControl().

Compatibility

Implemented only if both New Serial Manager Feature Set Version 2 and 4.0 New Feature Set are present. The SrmExtOpen function replaces the SrmOpen() function.

SrmExtOpenBackground Function ^TOP^

Purpose

Opens a port with the specified configuration in the background. Background ports relinquish control when another task opens the port with the SrmOpen() or SrmExtOpen() call.

Declared In

SerialMgr.h

Prototype

Err SrmExtOpenBackground (
   UInt32 port,
   SrmOpenConfigType *configP,
   UInt16 configSize,
   UInt16 *newPortIdP
)

Parameters

→ port: Physical or logical port number to be opened. See Port Constants for more information.
→ configP: Pointer to the configuration structure specifying the serial port's properties. See SrmOpenConfigType.
→ configSize: The size of the configuration structure pointed to by configP.
← newPortIdP: Contains the port ID to be passed to other Serial Manager functions.

Returns

This function returns the following error codes:

errNone: No error.
serErrAlreadyOpen: This port already has an installed background owner.
serErrBadPort: This port doesn't exist.
serErrNotSupported: This type of port cannot be opened in the background.
serErrBadParam: The configP parameter is NULL.
memErrNotEnoughSpace: There was not enough memory available to open the port.

Comments

This function is provided to support tasks that want to use a serial device to receive data only when no other task is using the port.

If a background port is forced to surrender control of the hardware as a result of another task opening a foreground connection, all buffers for the background port are flushed. After this active task closes the port, active control of the port is returned to the background task. Only one task can have background ownership of the port.

Note that background ports have limited functionality: they can only receive data and notify owning clients of what data has been received.

Compatibility

Implemented only if both New Serial Manager Feature Set Version 2 and 4.0 New Feature Set are present. The SrmExtOpenBackground function replaces the SrmOpenBackground() function.

SrmGetDeviceCount Function ^TOP^

Purpose

Returns the number of available serial devices.

Declared In

SerialMgr.h

Prototype

Err SrmGetDeviceCount (
   UInt16 *numOfDevicesP
)

Parameters

← numOfDevicesP: Pointer to address where the number of serial devices is returned.

Returns

errNone: No error.

Compatibility

Implemented only if New Serial Manager Feature Set Version 1 is present.

SrmGetDeviceInfo Function ^TOP^

Purpose

Returns information about a serial device.

Declared In

SerialMgr.h

Prototype

Err SrmGetDeviceInfo (
   UInt32 deviceID,
   DeviceInfoType *deviceInfoP
)

Parameters

→ deviceID: ID of serial device to get information for. You can pass a zero-based index (0, 1, 2, ...), a valid port ID returned from SrmOpen() or SrmExtOpen(), or a 4-character port name (such as 'u328', 'u650', or 'ircm'). See Port Constants.
← deviceInfoP: Pointer to a DeviceInfoType structure where information about the device is returned.

Returns

This function returns the following error codes:

errNone: No error.
serErrBadPort: This port doesn't exist.
serErrNoDevicesAvail: The Serial Manager cannot find any serial devices.

Compatibility

Implemented only if New Serial Manager Feature Set Version 1 is present.

SrmGetStatus Function ^TOP^

Purpose

Returns status information about the serial hardware.

Declared In

SerialMgr.h

Prototype

Err SrmGetStatus (
   UInt16 portId,
   UInt32 *statusFieldP,
   UInt16 *lineErrsP
)

Parameters

→ portID: Port ID returned from SrmOpen() or SrmExtOpen().
← statusFieldP: Pointer to address where hardware status information for the port is returned. This is a 32-bit field using the flags described in Status Constants.
← lineErrsP: Pointer to address where the number of line errors for the port is returned. The line error flags are described in Line Error Constants.

Returns

This function returns the following error codes:

errNone: No error.
serErrBadPort: This port doesn't exist.
serErrNotSupported: The port is a yielded port.
serErrNoDevicesAvail: No serial devices could be found.

Comments

Typically, SrmGetStatus is called to retrieve the line errors for the port if some of the send and receive functions return a serErrLineErr error code.

Compatibility

Implemented only if New Serial Manager Feature Set Version 1 is present.

SrmOpen Function ^TOP^

Purpose

Opens a foreground port connection with the specified port name or logical port number.

Declared In

SerialMgr.h

Prototype

Err SrmOpen (
   UInt32 port,
   UInt32 baud,
   UInt16 *newPortIdP
)

Parameters

→ port: The four-character port name or logical port number to be opened. See Port Constants for more information.
→ baud: Initial baud rate of port.
← newPortIdP: Contains the port ID to be passed to other Serial Manager functions.

Returns

This function returns the following error codes:

errNone: No error.
serErrAlreadyOpen: This port already has an installed foreground owner.
serErrBadPort: This port doesn't exist.
memErrNotEnoughSpace: There was not enough memory available to open the port.

Comments

Only one application or task may have access to a particular serial port at any time.

Do not keep the port open any longer than necessary. An open serial port consumes more energy from the device's batteries.

Compatibility

Implemented only if New Serial Manager Feature Set Version 1 is present.

If New Serial Manager Feature Set Version 2 is present, the SrmOpen function is replaced by SrmExtOpen(). SrmOpen is supported for backward compatibility.

SrmOpenBackground Function ^TOP^

Purpose

Allows a task to open, initialize, and use the port, but always relinquishes control of the port when another task opens the port with the SrmOpen() call.

Declared In

SerialMgr.h

Prototype

Err SrmOpenBackground (
   UInt32 port,
   UInt32 baud,
   UInt16 *newPortIdP
)

Parameters

→ port: The four-character port name or logical port number to be opened. See Port Constants for more information.
→ baud: Initial baud rate of port.
← newPortIdP: Contains the port ID to be passed to other Serial Manager functions.

Returns

This function returns the following error codes:

errNone: No error.
serErrAlreadyOpen: This port already has an installed background owner.
serErrBadPort: This port doesn't exist.
memErrNotEnoughSpace: There was not enough memory available to open the port.

Comments

This function is provided to support tasks that want to use a serial device to receive data only when no other task is using the port.

Note that background ports have limited functionality: they can only receive data and notify owning clients of what data has been received.

Compatibility

Implemented only if New Serial Manager Feature Set Version 1 is present.

If New Serial Manager Feature Set Version 2 is present, the SrmOpenBackground() function is replaced by SrmExtOpenBackground(). SrmOpenBackground() is supported for backward compatibility. If Palm OS Cobalt Feature Set is present, this function is unimplemented.

SrmPrimeWakeupHandler Function ^TOP^

Purpose

Sets the number of received bytes that triggers a call to the wakeup handler function.

Declared In

SerialMgr.h

Prototype

Err SrmPrimeWakeupHandler (
   UInt16 portId,
   UInt16 minBytes
)

Parameters

→ portId: Port ID returned from SrmOpen() or SrmExtOpen().
→ minBytes: Number of bytes that must be received before wakeup handler is called. Typically, this is set to 1.

Returns

This function returns the following error codes:

errNone: No error.
serErrBadPort: This port doesn't exist.
serErrNotOpen: The port is not open.
serErrNoDevicesAvail: No serial devices could be found.

Comments

This function primes a wakeup handler installed by SrmSetWakeupHandler().

Compatibility

Implemented only if New Serial Manager Feature Set Version 1 is present.

SrmReceive Function ^TOP^

Purpose

Receives a specified number of bytes.

Declared In

SerialMgr.h

Prototype

UInt32 SrmReceive (
   UInt16 portId,
   void *rcvBufP,
   UInt32 count,
   Int32 timeout,
   Err *errP
)

Parameters

→ portID: Port ID returned from SrmOpen() or SrmExtOpen().
← rcvBufP: Pointer to buffer where received data is to be returned.
→ count: Length of data buffer (in bytes). This specifies the number of bytes to receive.
→ timeout: The amount of time (in ticks) that the Serial Manager waits to receive the requested block of data. At the end of the timeout, data received up to that time is returned.
← errP: Error code.

Returns

Number of bytes of data actually received.

Comments

The following error codes can be returned in errP:

errNone: No error.
serErrBadPort: This port doesn't exist.
serErrNotOpen: The port is not open.
serErrTimeOut: Unable to receive data within the specified timeout period.
serErrConfigurationFailed: The port needs time to configure, and the configuration has failed.
serErrNotSupported: The port is not the foreground port.
serErrConfigurationFailed: The port could not configure itself.
serErrLineErr: A line error occurred during the receipt of data. Use SrmGetStatus() to obtain the exact line error.
serErrNoDevicesAvail: No serial devices could be found.

Compatibility

Implemented only if New Serial Manager Feature Set Version 1 is present.

SrmReceiveCheck Function ^TOP^

Purpose

Checks the receive FIFO and returns the number of bytes in the serial receive queue.

Declared In

SerialMgr.h

Prototype

Err SrmReceiveCheck (
   UInt16 portId,
   UInt32 *numBytesP
)

Parameters

→ portID: Port ID returned from SrmOpen() or SrmExtOpen().
← numBytesP: Number of bytes in the receive queue.

Returns

This function returns the following error codes:

errNone: No error.
serErrBadPort: This port doesn't exist.
serErrNotOpen: The port is not open.
serErrLineErr: A line error has occurred. Use SrmGetStatus() to obtain the exact line error.

Compatibility

Implemented only if New Serial Manager Feature Set Version 1 is present.

SrmReceiveFlush Function ^TOP^

Purpose

Flushes the receive FIFOs.

Declared In

SerialMgr.h

Prototype

Err SrmReceiveFlush (
   UInt16 portId,
   Int32 timeout
)

Parameters

→ portId: Port ID returned from SrmOpen() or SrmExtOpen().
→ timeout: Timeout value, in ticks.

Returns

This function returns the following error codes:

errNone: No error.
serErrBadPort: This port doesn't exist.
serErrNotOpen: The port is not open.
serErrNotSupported: The port is not the foreground port.
serErrNoDevicesAvail: No serial devices could be found.

Comments

The timeout value forces this function to wait a period of ticks after flushing the port to see if more data shows up to be flushed. If more data arrives within the timeout period, the port is flushed again and the timeout counter is reset and waits again. The function only exits after no more bytes are received by the port for the full timeout period since the last flush of the port. To avoid this waiting behavior, specify 0 for the timeout period.

Any errors on the line are cleared before this function returns.

Compatibility

Implemented only if New Serial Manager Feature Set Version 1 is present.

SrmReceiveWait Function ^TOP^

Purpose

Waits until some number of bytes of data have arrived into the serial receive queue, then returns.

Declared In

SerialMgr.h

Prototype

Err SrmReceiveWait (
   UInt16 portId,
   UInt32 bytes,
   Int32 timeout
)

Parameters

→ portID: Port ID returned from SrmOpen() or SrmExtOpen().
→ bytes: Number of bytes to wait for.
→ timeout: Timeout value, in ticks.

Returns

This function returns the following error codes:

errNone: No error.
serErrBadPort: This port doesn't exist.
serErrNotOpen: The port is not open.
serErrTimeOut: Unable to receive data within the specified timeout period.
serErrNotSupported: The port is not the foreground port.
serErrBadParam: The bytes parameter exceeds the size of the receive queue. Use SrmSetReceiveBuffer() to increase the size of the receive queue.
serErrLineErr: A line error occurred during the receipt of data. Use SrmGetStatus() to obtain the exact line error.
serErrNoDevicesAvail: No serial devices could be found.

Comments

If this function returns no error, the application can either check the number of bytes currently in the receive queue (using SrmReceiveCheck()) or it can just specify a buffer and receive the data by calling SrmReceive().

Do not call SerReceiveWait from within a wakeup handler. If you do, the serErrTimeOut error is returned.

Compatibility

Implemented only if New Serial Manager Feature Set Version 1 is present.

SrmReceiveWindowClose Function ^TOP^

Purpose

Closes direct access to the Serial Manager's receive queue.

Declared In

SerialMgr.h

Prototype

Err SrmReceiveWindowClose (
   UInt16 portId,
   UInt32 bytesPulled
)

Parameters

→ portId: Port ID returned from SrmOpen() or SrmExtOpen().
→ bytesPulled: Number of bytes the application read from the receive queue.

Returns

This function returns the following error codes:

errNone: No error.
serErrBadPort: This port doesn't exist.
serErrNotOpen: The port is not open.
serErrNotSupported: The port is not the foreground port.
serErrNoDevicesAvail: No serial devices could be found.

Comments

Call this function when the application has read as many bytes as it needs out of the receive queue or it has read all the available bytes.

Compatibility

Implemented only if New Serial Manager Feature Set Version 1 is present.

SrmReceiveWindowOpen Function ^TOP^

Purpose

Provides direct access to the Serial Manager's receive queue.

Declared In

SerialMgr.h

Prototype

Err SrmReceiveWindowOpen (
   UInt16 portId,
   UInt8 **bufPP,
   UInt32 *sizeP
)

Parameters

→ portId: Port ID returned from SrmOpen() or SrmExtOpen().
← bufPP: Pointer to a pointer to the receive buffer.
← sizeP: Available bytes in buffer.

Returns

This function returns the following error codes:

errNone: No error.
serErrBadPort: This port doesn't exist.
serErrNotOpen: The port is not open.
serErrNotSupported: The port is not the foreground port.
serErrLineErr: The data in the queue contains line errors.
serErrNoDevicesAvail: No serial devices could be found.

Comments

This function lets applications directly access the Serial Manager's receive queue to eliminate buffer copying by the Serial Manager. This access is a "back door" route to the received data. After retrieving data from the buffer, the application must call SrmReceiveWindowClose().

Applications that want to empty the receive buffer entirely should call the SrmReceiveWindowOpen and SrmReceiveWindowClose functions repeatedly until the buffer size returned is 0.

IMPORTANT: Once an application calls SrmReceiveWindowOpen, it should not attempt to receive data via the normal method of calling SrmReceive() or SrmReceiveWait(), as these functions interfere with direct access to the receive queue.

Compatibility

Implemented only if New Serial Manager Feature Set Version 1 is present.

SrmSend Function ^TOP^

Purpose

Sends a block of data out the specified port.

Declared In

SerialMgr.h

Prototype

UInt32 SrmSend (
   UInt16 portId,
   const void *bufP,
   UInt32 count,
   Err *errP
)

Parameters

→ portID: Port ID returned from SrmOpen() or SrmExtOpen().
→ bufp: Pointer to data to send.
→ count: Length of data buffer, in bytes.
← errP: Error code. See the Comments section for details.

Returns

Number of bytes of data actually sent.

Comments

When SrmSend returns, you should check the value returned in the errP parameter. If errNone, then the entire data buffer was sent. If not errNone, then the result equals the number of bytes sent before the error occurred. The possible error values are:

errNone: No error.
serErrBadPort: This port doesn't exist.
serErrNotOpen: The port is not open.
serErrTimeOut: Unable to send data within the specified CTS timeout period.
serErrNoDevicesAvail: No serial devices could be found.
serErrConfigurationFailed: The port configuration has failed.
serErrNotSupported: The specified port is not the foreground port.

Compatibility

Implemented only if New Serial Manager Feature Set Version 1 is present.

SrmSendCheck Function ^TOP^

Purpose

Checks the transmit FIFO and returns the number of bytes left to be sent.

Declared In

SerialMgr.h

Prototype

Err SrmSendCheck (
   UInt16 portId,
   UInt32 *numBytesP
)

Parameters

→ portID: Port ID returned from SrmOpen() or SrmExtOpen().
← numBytesP: Number of bytes left in the FIFO queue.

Returns

This function returns the following error codes:

errNone: No error.
serErrBadPort: This port doesn't exist.
serErrNotOpen: The port is not open.
serErrNotSupported: This feature not supported by the hardware.
serErrNoDevicesAvail: No serial devices could be found.

Comments

Not all serial devices support this feature.

Compatibility

Implemented only if New Serial Manager Feature Set Version 1 is present.

SrmSendFlush Function ^TOP^

Purpose

Flushes the transmit FIFO.

Declared In

SerialMgr.h

Prototype

Err SrmSendFlush (
   UInt16 portId
)

Parameters

→ portID: Port ID returned from SrmOpen() or SrmExtOpen().

Returns

This function returns the following error codes:

errNone: No error.
serErrBadPort: This port doesn't exist.
serErrNotOpen: The port is not open.
serErrNotSupported: The port is not the foreground port.
serErrNoDevicesAvail: No serial devices could be found.

Compatibility

Implemented only if New Serial Manager Feature Set Version 1 is present.

SrmSendWait Function ^TOP^

Purpose

Waits until all previous data has been sent from the transmit FIFO, then returns.

Declared In

SerialMgr.h

Prototype

Err SrmSendWait (
   UInt16 portId
)

Parameters

→ portID: Port ID returned from SrmOpen() or SrmExtOpen().

Returns

This function returns the following error codes:

errNone: No error.
serErrBadPort: This port doesn't exist.
serErrNotOpen: The port is not open.
serErrTimeOut: Unable to send data within the CTS timeout period.
serErrNotSupported: The port is not the foreground port.
serErrNoDevicesAvail: No serial devices could be found.

Comments

Consider calling this function if your software needs to detect when all data has been transmitted by SrmSend(). The SrmSend function blocks until all data has been transmitted or a timeout occurs. A subsequent call to SrmSendWait blocks until all data queued up for transmission has been transmitted or until another CTS timeout occurs (if CTS handshaking is enabled).

Compatibility

Implemented only if New Serial Manager Feature Set Version 1 is present.

SrmSetReceiveBuffer Function ^TOP^

Purpose

Installs a new buffer into the Serial Manager's receive queue.

Declared In

SerialMgr.h

Prototype

Err SrmSetReceiveBuffer (
   UInt16 portId,
   void *bufP,
   UInt16 bufSize
)

Parameters

→ portID: Port ID returned from SrmOpen() or SrmExtOpen().
→ bufP: Pointer to new receive buffer. Ignored if bufSize is NULL.
→ bufSize: Size of new receive buffer in bytes. To remove this buffer and allocate a new default buffer (512 bytes), specify NULL.

Returns

This function returns the following error codes:

errNone: No error.
serErrBadPort: This port doesn't exist.
serErrNotOpen: This port is not open.
memErrNotEnoughSpace: Not enough memory to allocate default buffer.
serErrNoDevicesAvail: No serial devices could be found.

Comments

The buffer that you pass to this function must remain allocated while you have the serial port open. Before you close the serial port, you must restore the default queue by calling SrmSetReceiveBuffer with NULL as the bufP and bufSize arguments.

IMPORTANT: Applications must install the default buffer before closing the port (or disposing of the new receive queue).

Compatibility

Implemented only if New Serial Manager Feature Set Version 1 is present.

SrmSetWakeupHandler Function ^TOP^

Purpose

Installs a wakeup handler.

Declared In

SerialMgr.h

Prototype

Err SrmSetWakeupHandler (
   UInt16 portId,
   WakeupHandlerProcPtr procP,
   UInt32 refCon
)

Parameters

→ portID: Port ID returned from SrmOpen() or SrmExtOpen().
→ procP: Pointer to a WakeupHandlerProcPtr() function. Specify NULL to remove a handler.
→ refCon: User-defined data that is passed to the wakeup handler function. This can be a pointer or not.

Returns

This function returns the following error codes:

errNone: No error.
serErrBadPort: This port doesn't exist.
serErrNotOpen: The port is not open.
serErrNoDevicesAvail: No serial devices could be found.

Comments

The wakeup handler is a function in your application that you want to be called whenever there is data ready to be received on the specified port.

The wakeup handler function will not become active until it is primed with a number of bytes that is greater than 0, by the SrmPrimeWakeupHandler() function. Every time a wakeup handler is called, it must be re-primed (using SrmPrimeWakeupHandler) in order to be called again.

Compatibility

Implemented only if New Serial Manager Feature Set Version 1 is present.

Serial Manager Application-Defined Functions ^TOP^

WakeupHandlerProcPtr Function ^TOP^

Purpose

Called after some number of bytes are received by the Serial Manager's interrupt function.

Declared In

SerialMgr.h

Prototype

void (
   *WakeupHandlerProcPtr
)(
   UInt32 refCon
)

Parameters

→ refCon: User-defined data passed from the SrmSetWakeupHandler() function.

Returns

Returns nothing.

Comments

This handler function is installed by calling SrmSetWakeupHandler(). The number of bytes after which it is called is specified by SrmPrimeWakeupHandler().

IMPORTANT: Because wakeup handlers are called during interrupt time, they cannot call any Palm OS^® system functions, including SrmReceive(), that may block the system in any way. Wakeup handlers should also be very short so as to reduce interrupt latency.

Two common implementations of wakeup handlers include:

Calling EvtWakeup(), which causes any pending EvtGetEvent call to return and then sends a nilEvent to the current application.
Using SrmReceiveWindowOpen() and SrmReceiveWindowClose() to gain direct access to the receive queue without blocking.

Compatibility

Implemented only if New Serial Manager Feature Set Version 1 is present.

70 Serial Manager

Serial Manager Data Structures ^TOP^

DeviceInfoType Struct ^TOP^

Purpose

Prototype

Fields

SrmCtlEnum Enum ^TOP^

Purpose

Prototype

Constants

Compatibility

SrmOpenConfigType Struct ^TOP^

Purpose

Prototype

Fields

Compatibility

Serial Manager Constants ^TOP^

Port Constants ^TOP^

Logical Serial Port Constants

Compatibility

Physical Serial Port Constants

Virtual Serial Port Constants

Compatibility

Serial Capabilities Constants ^TOP^

Compatibility

Serial Settings Constants ^TOP^

Status Constants ^TOP^

Line Error Constants ^TOP^

Serial Manager Functions ^TOP^

SrmClearErr Function ^TOP^

Purpose

Declared In

Prototype

Parameters

Returns

Compatibility

SrmClose Function ^TOP^

Purpose

Declared In

Prototype

Parameters

Returns

Comments

Compatibility

See Also

SrmControl Function ^TOP^

Purpose

Declared In

Prototype

Parameters

Returns

Comments

Compatibility

See Also

SrmCustomControl Function ^TOP^

Purpose

Declared In

Prototype

Parameters

Returns

Comments

Compatibility

See Also

SrmExtOpen Function ^TOP^

Purpose

Declared In

Prototype

Parameters

Returns

Comments

Compatibility

See Also

SrmExtOpenBackground Function ^TOP^

Purpose

Declared In

Prototype

Parameters

Returns

Comments

Compatibility