I2C Multi-byte Slave to Master?

[dpaul]

Is it possible to program a I2C Master-Slave system with multi-byte Slave to Master communications with the compilier I2C_XX() functions? If so, could code snippets be posted?

I have no trouble with multi-byte Master to Slave communications, but going the other way, things are limited. Following a Master I2C_Write() with the seven bit address and LSB set followed in the Master with an I2C_Read (), I can communicate a single byte from the from the Slave with a I2C_Write() call. The Master does not Acknowledge, and investigation with a scope shows the SCL line remains low, which renders my I2C bus in an permanent "Clock Stretching" mode.

I've tried a days worth of various register twiddling in conjunction with the I2C_XX() function calls to no avail. Can multi-byte Slave to Master be done with the high level compiler functions? Searching this forum shows only code examples with elaborate register bit manipulation claiming multi-byte Slave to Master communications. Is this the only way to get this done?

Thanks for any advice, or hopefully code.

Doug

[Mark]

Did your slave transmit any more data?? The slave was holding the clock low waiting on you to do another write. You have to check the return value of the I2C_Write to see if the slave is supposed to continue writing. Take a look at this old post where I modified the CCS example program to do what you want. Note the ssp int can be quite long doing it this way and I wouldn't do it but you can do it as a test. I would probably set a flag and handle it in the main loop.

http://www.ccsinfo.com/forum/viewtopic.php?p=6851#6851