TWI / I2c device unable to read / write the device ? irrespective of following reference manual.

RE: TWI / I2c device unable to read / write the device ? irrespective of following reference manual.

Stian Røed Hafskjold — Mon, 08 Jun 2015 07:28:24 GMT

It is the check mark under the voting buttons to the left of the answer.

RE: TWI / I2c device unable to read / write the device ? irrespective of following reference manual.

Faizan — Fri, 05 Jun 2015 14:49:49 GMT

Where is the answer accepted button, which i need to click after getting satified answer? i looked for a while but didn't find any .

RE: TWI / I2c device unable to read / write the device ? irrespective of following reference manual.

Faizan — Mon, 01 Jun 2015 13:37:56 GMT

Thanks a lot for the answer. Do i need to setup the pull up resistor for the PSELSCL and PSELSDA ?? or its enough to configure those pins as input and SODI (as per the data sheet)

RE: TWI / I2c device unable to read / write the device ? irrespective of following reference manual.

Stian Røed Hafskjold — Mon, 01 Jun 2015 09:47:11 GMT

The shifting is just a part of the TWI specification. TWI uses 7 bit addressing + a read/write bit: www.totalphase.com/.../200349176-7-bit-8-bit-and-10-bit-I2C-Slave-Addressing

So when using the TWI driver in the SDK you need to shift the address one bit left and add the R/W bit as LSB before passing the resulting uint8_t variable to the TWI functions.

If you write to the ADDRESS register directly, you can see in the data sheet that it consists of 7 bits, so no shifting is necessary.

You do not need any external pull ups for the SCL and SDA. When the PSELSCL and PSELSDA registers are set the pins are configured correctly.

RE: TWI / I2c device unable to read / write the device ? irrespective of following reference manual.

Faizan — Mon, 01 Jun 2015 09:24:11 GMT

I am unable to read the data from the defined address from the slave device. After googling for a while i found that the address need to shifted to the right by 1in one post and in the other it said to the left by 1. Now i am confused to which side? even if i figure out by hit and trial method. I am not sure why the address needs to be shifted out by 1.... Since, its nowhere mentioned in data sheet or any thing related to shifting of address. and do i need to pull up the pins of scl and sda ????

RE: TWI / I2c device unable to read / write the device ? irrespective of following reference manual.

Stian Røed Hafskjold — Thu, 28 May 2015 14:41:52 GMT

Why are you using the register addresses instead of the register names defined in nrf51.h? It makes your code really hard to read.

There is a TWI driver in the SDK that you can use instead of making all the low level functions your self. developer.nordicsemi.com/.../a00016.html

Also, can you please update your question with what is actually not working. If you are able to see any activity at all using a logic analyzer or oscilloscope, and your test setup in general. How do you know it doesn't work?