topic Re: MC9S08QE32 SCI in 8-bit Microcontrollers

MC9S08QE32 SCI

maoxiangyu — Wed, 12 Dec 2012 05:38:51 GMT

Hi,

I encountered a problem when using SCI. The data in SCI is incorrect and when I send three different data "A" “B” “C”, it return the value of "61" "21" "38", Can you tell me why?

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Re: MC9S08QE32 SCI

donw — Wed, 12 Dec 2012 06:22:43 GMT

Usually the problem is either:

-Baud rate is wrong

-the Invert bit in the config registers is the wrong polarity.

To check the baud rate, send out a 55 (hex) value out the transmitter & look at the result on a 'scope

you should see a square wave. (or use a dumb terminal, should show U character)

don

Re: MC9S08QE32 SCI

maoxiangyu — Wed, 12 Dec 2012 06:35:36 GMT

Hi, don

The Baud rate is correct for it has been tested in MC9S08QE128 by FAE of FreeScale in ShangHai and he made it clear that the program works ok in his DEMO Board!

We've send out a 55 (hex) value out the transmitter and MCU returns 0x55, but only this number correct! The dumb terminal shows the same result when MCU send datas!

Re: MC9S08QE32 SCI

Lundin — Wed, 12 Dec 2012 09:28:35 GMT

You have to measure the baudrate on your board. It might have a different clock setup.

Re: MC9S08QE32 SCI

maoxiangyu — Thu, 13 Dec 2012 08:25:57 GMT

Hi, Daniel

The problem has been solved, it turned out to be the problem of MAX3232. This level switch chip was damaged and the voltage in Serial Port changed, thank you all!