UART Communication

[blakehodder]

Hi,

I am using a MCF52255 and trying to use the UART without using the RTOS. Could someone please point me in the direction of an app note or other documentation on this.

Regards,

Blake

[DavidS · Accepted solution]

Hi Blake,

You can goto the MCF5225x product page on the Freescale website (or google it) and select the Software/Tools tab.

It has baremetal example code:

MCF5225X_SAMPLE_CODE: MCF5225x_SAMPLE_CODE.

Size (K): 1427 Format: zip Rev #: 0 Modified: 12/22/2008

Please note that as product age, so do the examples implying that the latest IDE's like CW10.x might not be supported.

Regards,

David

[blakehodder]

Hi David,

I now have my uart working at the right baud but when I am sending something such as 0x4A its sends ok but will change to 0x29.

What would cause this?

Blake

[DavidS]

Hi Blake,

Are you setup a simple MCF52259 to a PC terminal window?

Have you oscoped the output?

Regards,

David

[blakehodder]

Hi David,

I was over pushing my uart. The MCU was running at such a rate that since I was only sending a value with my program that the uart was not keeping up with the MCU. Once I stuck the delay in, it functioned perfect.

Thanks for all your help.

Blake

[blakehodder]

Hi David,

Actually at the moment I am connected to a PC via a logic analyzer. If I send 0x55 it works no problem and always sends 0x55 but when I send 0x4A or other values thats when it changes. This is how I send it:

void putc(char val)

{

  while(!(MCF_UART0_USR & MCF_UART_USR_TXRDY) || !(MCF_UART0_USR & MCF_UART_USR_TXEMP) ){

  }

  MCF_UART0_UTB = val;

}

Blake