ISP problem

terryhao · ‎2003-05-26

Posted on May 27, 2003 at 08:59

ISP problem

terryhao · ‎2003-05-26

Posted on May 27, 2003 at 08:10

Dear Sir,

I use ST7MDT2-DVP2 to program St72C334N4T6 by using ISP. First I can program the programm area(I forgot to program the option byte) and then the program can work. But now I can not program with ISP.

I don't know why? I measure the Reset pin and ISPSEL pin and found that the Reset Pin is OK and I can see 33 clock on ISPSEL pin but the bottom level of ISPSEL is about -1V. the voltage of ISPCLK and ISPDATA pin is always 0V. could anyone help me? Thanks a lot!

sjo · ‎2003-05-26

Posted on May 27, 2003 at 08:59

It sounds like you have corruputed the option bytes, try applying an external clock to the OSC1 pin, this may help you recover.

Regards

Spen