twbbif.c File Reference


Detailed Description

Bit banging two wire interface.

Tested with AT91R40008 only. Other ARMs or AVR may not work.

 *
 * $Log: twbbif.c,v $
 * Revision 1.10  2008/02/15 17:04:49  haraldkipp
 * Spport for AT91SAM7SE512 added.
 *
 * Revision 1.9  2007/10/04 20:16:57  olereinhardt
 * Support for SAM7S256 added
 *
 * Revision 1.8  2007/07/09 13:38:50  olereinhardt
 * 2007-07-09  Ole Reinhardt <ole.reinhardt@embedded-it.de>
 *         * dev/twbbif.c: Added default TWI_DELAY for avr architecture
 *         to allow in-tree compilation
 *         * net/Makefile: Commented out igmp support as long as it does
 *         not exists to allow in-tree compilation
 *
 * Revision 1.7  2007/02/15 16:25:40  haraldkipp
 * Configurable port bits. Should work now on all AT91 MCUs.
 *
 * Revision 1.6  2006/10/08 16:48:09  haraldkipp
 * Documentation fixed
 *
 * Revision 1.5  2006/06/28 17:10:35  haraldkipp
 * Include more general header file for ARM.
 *
 * Revision 1.4  2006/05/25 09:30:23  haraldkipp
 * Compiles for AVR. Still not tested, though.
 *
 * Revision 1.3  2006/04/07 12:50:20  haraldkipp
 * Added additional delays in TwAck.
 * Clock and data forced to high before switching to input gives better
 * waveforms.
 * Additional delay added to set clock to 50% duty cycle. The PCF8563
 * seems to fail, if the clock's high time is much longer than the low time.
 *
 * Revision 1.2  2006/01/23 17:32:35  haraldkipp
 * Automatic initialization added.
 *
 * Revision 1.1  2005/10/24 10:21:57  haraldkipp
 * Initial check in.
 *
 *
 * 

Definition in file twbbif.c.

Go to the source code of this file.

Functions

int TwMasterTransact (u_char sla, CONST void *txdata, u_short txlen, void *rxdata, u_short rxsiz, u_long tmo)
 Transmit and/or receive data as a master.
int TwMasterError (void)
 Get last master mode error.
int TwSlaveListen (u_char *sla, void *rxdata, u_short rxsiz, u_long tmo)
 Listen for incoming data from a master.
int TwSlaveRespond (void *txdata, u_short txlen, u_long tmo)
 Send response to a master.
int TwSlaveError (void)
 Get last slave mode error.
int TwIOCtl (int req, void *conf)
 Perform TWI control functions.
int TwInit (u_char sla)
 Initialize TWI interface.


Function Documentation

int TwSlaveListen ( u_char sla,
void *  rxdata,
u_short  rxsiz,
u_long  tmo 
)

Listen for incoming data from a master.

If this function returns without error, the bus is blocked. The caller must immediately process the request and return a response by calling TwSlaveRespond().

Note:
Slave mode is not implemented in the bit banging version. Thus the function always returns -1.
Parameters:
sla Points to a byte variable, which receives the slave address sent by the master. This can be used by the caller to determine whether the the interface has been addressed by a general call or its individual address.
rxdata Points to a data buffer where the received data bytes are stored.
rxsiz Specifies the maximum number of data bytes to receive.
tmo Timeout in milliseconds. To disable timeout, set this parameter to NUT_WAIT_INFINITE.
Returns:
The number of bytes received, -1 in case of an error or timeout.

Definition at line 657 of file twbbif.c.

int TwSlaveRespond ( void *  txdata,
u_short  txlen,
u_long  tmo 
)

Send response to a master.

This function must be called as soon as possible after TwSlaveListen() returned successfully, even if no data needs to be returned. Not doing so will completely block the bus.

Note:
Slave mode is not implemented in the bit banging version. Thus the function always returns -1.
Parameters:
txdata Points to the data to transmit. Ignored, if the number of bytes to transmit is zero.
txlen Number of data bytes to transmit.
tmo Timeout in milliseconds. To disable timeout, set this parameter to NUT_WAIT_INFINITE.
Returns:
The number of bytes transmitted, -1 in case of an error or timeout.

Definition at line 680 of file twbbif.c.

int TwSlaveError ( void   ) 

Get last slave mode error.

You may call this function to determine the specific cause of an error after TwSlaveListen() or TwSlaveRespond() failed.

Returns:
Error code or 0 if no error occurred.
Note:
Slave mode is not implemented in the bit banging version. Thus the function always returns TWERR_BUS.

Definition at line 696 of file twbbif.c.

References TWERR_BUS.


© 2000-2007 by egnite Software GmbH - visit http://www.ethernut.de/