topic KE04Z8 TX Problem in Kinetis Microcontrollers

KE04Z8 TX Problem

davidra7 — Wed, 17 Feb 2016 08:33:56 GMT

Hey ,

I using the MKE04Z8 device on my pcb , my problem is that I can't see anything in the line.

I configure the PTA2 as RX PTA3 as TX and used the next basic code:

/* Write your local variable definition here */

byte packet[2]={100,100};

word sent ;

byte retval;

/*** Processor Expert internal initialization. DON'T REMOVE THIS CODE!!! ***/

PE_low_level_init();

/*** End of Processor Expert internal initialization. ***/

/* Write your code here */

/* For example: for(;;) { } */

while(1)

{

AS1_SendBlock(packet,2,&sent);

}

what I done:

1. I configured the next code on PTB0 and PTB1 and it send data.

2. I took the pin of the PTA3 and disconnected it from the pcb and still no output signal.

3. I tried the code on the FRDM and it worked.

4. I tried it on more then 1 PCB Board with different devices.

5. I work on eclipse code warrior and I tried it on kinetis design studio and still not working.

I think that is something on the pin(PTA3) configuration , Any suggestions ?

BTW, The RX line works perfectly and I am attaching picture of the codewarrior window

Thanks,
David

Re: KE04Z8 TX Problem

Stano — Wed, 17 Feb 2016 08:46:04 GMT

Hello David,

The PTA2 and PTA3 are true open-drain pins, so the external pull-ups have to be used for these pins. I suggest you to use resistors of 5-10k, but it depends on real application too. Please try it and let me know the result.

Best Regards,

Stano.

Re: KE04Z8 TX Problem

davidra7 — Wed, 17 Feb 2016 10:30:12 GMT

Hi,

Thanks for the fast answer, I connected it to 5K pull up and it works :smileyhappy:

Can I use the Internal Pull up for PTA3?

Thanks,
David

Re: KE04Z8 TX Problem

Stano — Wed, 17 Feb 2016 14:59:50 GMT

Hi David,

yes, you can used the internal pull-up, but it is quite weak - it is about 50kOhm (30 - 60k). So better is to use 5k external resistor for better noise immunity.

Best Regards,

Stano.