TM4C1294 I2C

user1008226

I’m using a MCP4725 digital to analog (DAC) converter with the TM4C1294 communicating using an I2C port. The sample rate of the DAC is defined by the speed of the I2C port and I would like to use the converter at its maximum sample rate (~180 ksps using High speed mode: 3.4 mbps). Another consideration is that I need to send more than 255 bytes to the DAC.

I’m trying to use the FIFO for sending the data but it seems to limit the number of byte sent to 255. Is correct? Or I’m not configuring correctly the port.

The I2C port correctly sent 255 bytes and after that automatically sent the stop condition even if I do not use the I2C_MASTER_CMD_FIFO_BURST_SEND_FINISH master control command (TivaWare™ Peripheral Driver Library).

Any idea? Thanks

over 8 years ago

0 Amit Ashara over 8 years ago

TI__Guru**** 244400 points

Hello User1008226

Please refer to the application note for I2C on TM4C129x device class and the example code that comes along with it

www.ti.com/.../spma073.pdf

0 user1008226 over 8 years ago in reply to Amit Ashara

Prodigy 100 points

I have already read the document, in fact, thanks to the examples I could operate the port. In all examples it is set as maximum amount of data to 255 and no more. This limitation appears to be due to the limitation of the burst length register.
Hence my question: can we use the FIFO to send more than 255 bytes? Without having to do the START procedure again.
regards

0 Amit Ashara over 8 years ago in reply to user1008226

TI__Guru**** 244400 points

Hello User1008226

You may be able to do it with a Repeated Start but not without issuing a START condition at all.

0 user1008226 over 8 years ago in reply to Amit Ashara

Prodigy 100 points

Thank you
Vicente

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TM4C1294 I2C