MC33905S Exercising I/O-3

[iamtawit]

I am using MC33905S for my application, as power regulator and CAN transceiver, in Normal mode and is working fine so far. However, I can't make the I/O-3 to drive a small LED.

What I have done is, during Initializing the LIN and I/O I set the LIN_T2[1], LIN_T2[0] bits to '10' for 'pin operation as I/O: HS switch and Wake-up input'

And when in Normal mode I set the I/O register I/O-3 [1], I/O-3 [0] to '11' for 'I/O-3 HS driver enable' which should bring the I/O-3 pin to Vsup2 voltage and drive my LED ... but it doesn't.

Can anyone point-out what did I missed? I can control I/O-0 and I/O-1 just fine but not I/O-3. 

[iamtawit · Accepted solution]

I found a problem ... here is what happened. Even though I disable LIN_T1 and LIN_T2, termination pin of LIN1 and LIN2 and configure both pins to function as I/O as mentioned in the first post, I also have to disable both LIN module as well via LIN/1 and LIN2 register setting LIN mode[1] and LIN mode[0] to '01' (not used).

And now I can control I/O-3 via I/O register by set it to either '00' or '11'.

Hopefully this will help everybody facing this issue.

[iamtawit]

Connection is very simple, just resistor and LEDs.

[guoweisun]

Hi

Could you please show your schematic for us?

Thanks!