Class OSDeviceCharacterBuffered - DEPRECATED

Page date Sat Mar 5 00:22:16 2011 .

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Classes hierarchy

• streambuf
  • OSDeviceCharacter
    • OSDeviceCharacterBuffered

The OSDeviceCharacter class may or may not derive from streambuf, based on configuration variables.

Children classes

• OSDeviceCharacterBufferedUsart0
• OSDeviceCharacterBufferedUsart1

Overview

The OSDeviceCharacterBuffered class implements circular receive/transmit buffers. It is the parent class for devices like USART.

OSDeviceCharacterBuffered is an abstract class, requiring children classes to implement the actual read/write code.

Constructors

OSDeviceCharacterBuffered(unsigned char *pRxBuf, unsigned short rxBufSize, unsigned short rxHWM, unsigned short rxLWM, unsigned char *pTxBuf, unsigned short txBufSize, unsigned short txHWM, unsigned short txLWM)

Description

Initialize the buffered character device with the given circular buffers and with custom water mark values.

Parameters

:* pRxBuf - pointer to receive buffer

:* rxBufSize - size of receive buffer

:* rxHWM - receive high water mark

:* rxLWM - receive low water mark

:* tRxBuf - pointer to transmit buffer

:* txBufSize - size of transmit buffer

:* txHWM - transmit high water mark

:* txLWM - transmit low water mark

Return value

:* none

OSDeviceCharacterBuffered(unsigned char *pRxBuf, unsigned short rxBufSize, unsigned char *pTxBuf, unsigned short txBufSize)

Description

Initialize the buffered character device with the given circular buffers and default 1/4 low and 3/4 high water mark values.

Parameters

:* pRxBuf - pointer to receive buffer

:* rxBufSize - size of receive buffer

:* tRxBuf - pointer to transmit buffer

:* txBufSize - size of transmit buffer

Return value

:* none

Virtual Methods

virtual OSReturn_t implOpen(void)

Description

Call implPortInit() to open the device.

Parameters

:* none

Return value

:* status

virtual OSReturn_t implClose(void)

Description

Call implPortDisable() to close the device.

Parameters

:* none

Return value

:* status

virtual bool implIsConnected(void) const

Description

Check if the device is connected. Not yet fully implemented, currently just returns returns true.

Parameters

:* none

Return value

:* true if the device is connected

virtual bool implCanRead(void)

Description

Check if the receive buffer is not empty.

Parameters

:* none

Return value

:* true if characters are available for read

virtual int implAvailableRead(void)

Description

Return the number of available characters in the receive buffer.

Parameters

:* none

Return value

:* number of available characters

virtual int implReadByte(void)

Description

Return the next byte available in the receive buffer.

Parameters

:* none

Return value

:* return byte or negative if an error occur

virtual bool implCanWrite(void)

Description

Check if the transmit buffer is not full.

Parameters

:* none

Return value

:* true if transmit queue not full

virtual int implWriteByte(unsigned char b)

Description

Add one byte to the transmit buffer. If above high water mark, start transmission by enabling transmit interrupts.

Parameters

:* none

Return value

:* status

virtual int implFlush(void)

Description

If the transmit buffer is above high water mark, start transmission by enabling transmit interrupts.

Parameters

:* none

Return value

:* status of the operation

Methods

void interruptRxServiceRoutine(void)

Description

Implement the receive interrupt service routine. Read from the device and if the receive buffer is not full, insert in it.

Parameters

:* none

Return value

:* none

void interruptTxServiceRoutine(void)

Description

Implement the transmit interrupt service routine. If the transmit buffer is empty, disable transmit interrupts. Get one byte from the transmit buffer and write it to the device. If the buffer is below the low water mark, notify writer to send more bytes.

Parameters

:* none

Return value

:* none

Abstract Methods

== virtual int implPortInit(void) = 0 ==

virtual int implPortDisable(void)

== virtual void implInterruptTxEnable(void) = 0 ==

== virtual void implInterruptTxDisable(void) = 0 ==

== virtual unsigned char implPortRead(void) = 0 ==

== virtual void implPortWrite(unsigned char b) = 0 ==

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