i2c communication problems

[billt79]

Hi,

I have been having a lot of problems communicating with an Atmel SAM D09 as a slave, and an nrf51422 as a master.

I seem to have two problems, hopefully solving just one will get me where I need to be. but I can't seem to narrow it down. The first issue, I have been trying to use a slightly modified twi_sw_master.c to communicate with the slave, this has worked with plenty of other i2c devices out there, like EEPROMs Acelerometers, and PMICs however the Atmel won't ack. The reason I believe this to be a problem, is it doesn't run at exactly 100Khz (best i can get is 94Khz), this seems highly unlikely to me, but it is the only thing that is apparent as the Atmel is returning no error while polling the interrupt flags, and all the config is set as required. It is also pulling up both of its i2c pins, which would indicate that it is working. I have done plenty of debugging with uart, and all seems normal.

To get around this i have tried using twi_hw_master.c to work, and i do get 100Khz exactly, however the waveform i see on my scope looks wrong. To my understanding, there are 9 clock pulses on SCL, the last one being for an ack/nack, this was present on the sw version, but on the hw version it is not present and there also does not appear to be a valid stop condition, although no data is being transferred due to the lack of an ack. My aim is to use the self programming function of the Atmel SAM to update it OTA via the BLE on the nrf. the code on the Atmel is from the ASF, so i can be quite sure it works. Also worth noting that the Atmel chip is configured to respond to any address between 0-127 regardless. Unfortunately for me i am very restricted on GPIOs on the nrf, so using something else is out of the question.

[billt79]

I will try it with an arduino,although i will need to pick on up. The code i am using is an example from the ASF, and is configured just fine. There are only 2 sets of pins which work with i2c. i have also tried the default ones in the example application but i would like to use the other two. The Atmels do have a large amount of config required, however most of what i need is default anyway, so all i have to do is get the defaults, and then modify what i need and then initialise, this seems to be working fine, returns status_ok. The i2c driver on the atmel is currently running in polled mode, so i disabled the timeout so it infinatley waits for a packet, but the flags never fire. Also there is good reason to be using the bit bashing code, as we have some specific requirements and half our boards are the rev1 chips. only recently did we get a new batch with rev3.