RE: TWI ISSUE

HPC — Thu, 26 Jun 2014 17:56:15 GMT

Basically what I2C is , it is a two wire interface SCL for clock and SDA for data and it requires a pullup resistor to operate properly .So my question is

Why have you connected two pins (11 & 26 together) and (10 and 27 together)?

NOTE: Suppose if 26 is configured as SCL and 11 is a gpio which is of NO_PULL type,it will pull down the voltage levels of I2C bus and will fail to function properly.

In twi_hw_master.c the PULL UP is enabled for both SCL and SDA , no need to worry (GPIO_PIN_CNF_PULL_Pullup << GPIO_PIN_CNF_PULL_Pos)

3.DEBUGGING

 a)  Verify the slave address you're using is correct , the API uses addes in a manner
  "7bits" + "read/write bit" eg: 1110011+0  ie;0xE6 (last bit 0 indicates writing bit)
 b) Connect a CRO and verify that the voltage levels are as expected and slave is producing a NACK which is possibly a wrong slave address

RE: TWI ISSUE

thomas — Wed, 21 May 2014 14:15:32 GMT

Any help ?

RE: TWI ISSUE

thomas — Wed, 21 May 2014 09:34:50 GMT

I'm working on a custom board and i can't access to the twi bus with an logic analyzer... Pins used by the twi interface are configured on the tw_master_config file.