Edge Selection Bit by ST6220

[the2nd]

Posted on March 26, 2003 at 05:07

Edge Selection Bit by ST6220

[the2nd]

Posted on March 19, 2003 at 10:48

I have a problem with the ST62E20 microcontroller. I try to build a connection with a PC using the RS232. I receive the RD information on the PB3 pin, it's configured as a input with interrupt (ddrb=0f7h, orb=0ffh, drb=0), the Edge Selection Bit of ior is set to 0, but in fact the interrupt is called when the rising edge occures. I tryed to set ESB to 1, but had no changes. What should I do? With best regards, Aleksej

[rolf]

Posted on March 25, 2003 at 08:32

Hi Aleksej,

normally the edge selection bit should work fine. How did you access the IOR? Please be aware that SET and RES instructions are not allowed on this register because it is write only.

Attached there is an example for a RS232 communiacation in software for ST62 with 9600baud. Maybe it could be an example for your application?

Ciao,

Rolf

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Attachments :

RS232_96.asm : https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006I0DS&d=%2Fa%2F0X0000000bXL%2F6A4PHmNJANCR42KrdRg1.u1IuSeAkA19TI7TdsFiG9g&asPdf=false

[the2nd]

Posted on March 26, 2003 at 05:07

Thank you, Rolf!

It seems to be working, I had the same problem with the ST6260 MCU, I thought it was the fault of POWER-ON-RESET, but it was really the read-protection of ior register, I didn't know that it's so important, there are many instructions like ''set 4, ior'' in my book, but I've already found some mistakes, it should be the next one.

Thanks a lot for your help, it's really kind!