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SPI interrupt at wrong address

Donghua Gu

I am using Atmel AT89C51CC03, and it is configured so in Keil too. The data sheet lists the SPI interrupt vector as 0x0053h, and I do define my interrupt as interrupt #10. However, the map file show my SPI interrupt has address of 0x0026h.

Does anyone know why is that? Anything I can do to make it right?

Thanks in advance!

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  • 0 in reply to Andy Neil

    You guys are right. I do have a LJMP at 0x53.
    Then I still do not know what causes my problem. In my interrupt routine, I basically toggle P4_0, but on my scope, I can see the P4_0 toggles even when chip select is high. Too bad that I can not post screen shot here, but basically my MOSI rest at 2.7V, and every 12.5 usec, there are two small pulses pull the voltage to 3.6V. P4_0 toggles at the rising edge of the first small pulse, and my chip select is solid high. I know the voltage is a little strange and I don't know what cause these small pulses, but if the chip select is high, then it should not trigger interrupt at all, right?
    Any suggestions?
    Thanks,

Reply
  • 0 in reply to Andy Neil

    You guys are right. I do have a LJMP at 0x53.
    Then I still do not know what causes my problem. In my interrupt routine, I basically toggle P4_0, but on my scope, I can see the P4_0 toggles even when chip select is high. Too bad that I can not post screen shot here, but basically my MOSI rest at 2.7V, and every 12.5 usec, there are two small pulses pull the voltage to 3.6V. P4_0 toggles at the rising edge of the first small pulse, and my chip select is solid high. I know the voltage is a little strange and I don't know what cause these small pulses, but if the chip select is high, then it should not trigger interrupt at all, right?
    Any suggestions?
    Thanks,

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