Topic : Ride ST7 Simulator trouble

Forum : ST7/STM8

Original Post
Post Information Post
November 23, 2007 - 12:15pm
Guest

I use ride(bn747) st7 Simulator debug.But when i try write or read SCIDR(51H), the SCISR(50H) not any changer.
the result is that the program was running SCI interrupt over and over again.
Example:Reset,SCISR=0C0H,I try do :LD SCIDR,A , but SCISR still be 0c0h.
why?

Target:ST72324X4

Thank you!
Replies
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November 23, 2007 - 3:40pm
Raisonance Support Team

Hi,

SCISR has value C0h, as bits 7 and 6 are set. This means (bit 7) transmit data register is empty and (bit 6) transmission is complete. That just means the SCI is ready to send or receive, nothing in its buffer in either direction.

Bruno
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November 23, 2007 - 3:54pm
Guest

Sorry,i make a mistake.Example:Reset,SCISR=0C0H,I try do :LD SCIDR,A , but SCISR still be 0c0h.
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November 27, 2007 - 10:20am
Raisonance Support Team

You are right.
If you read the datasheet for your device, you will note that bit 7 and 6 of SCISR are flags indicating the status of the SCI. These flags report whether the peripheral is "empty" or not. So even if you reset the flags to 0, they will eventually (and automatically) come back to 1 when the SCI buffers are free.

I hope this helps.
Bruno