8-bit Microcontrollers中的主题 Re: MC9S08JM32 SCI question

MC9S08JM32 SCI question

Betadine — Thu, 03 Feb 2011 22:41:34 GMT

Hi All,

Is the first time I write the SCI code for RS232. The Processor Expert helps a lot, but I can´t understand a very simple question:

Why I must activate interrupts for sending and receiving more than one character?

I only can edit the buffer size once I activate the IRQs... why it´s linked?

Am I missing something?

Cheers.

Re: MC9S08JM32 SCI question

peg — Fri, 04 Feb 2011 05:00:04 GMT

Hello,

This must be a limitation imposed by Processor Expert as there is no necessity to do so imposed at the chip level. As long as you can poll in less than a byte time you don't need receive interrupts and unless there is some timing requirement imposed by the other end of your link you don't need transmit interrupts.

Re: MC9S08JM32 SCI question

Betadine — Fri, 04 Feb 2011 17:53:24 GMT

Ok, I will make some tests... more clearly now

Receiving from the PC can be usefull to use the RxInterrupt in the MCU?

My program is very simple. PC says: "hey! send the data, and the MCU answers.

Independtly of stop and wait mode, I think it´s more gently to "wake up" the MCU through the interrupt instead of seeking the buffer constantly in the main loop.

So I think this is the common way to receive data from the PC...

Thanks