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09/20/04 23:56
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 		 #77757 - RE: AT89S8252 ISP via SPI
Responding to: ???'s previous message
You are using the AT89S8252 as the slave. Have you enabled the internal pull-ups on the MISO line ?


My understanding is that the AT89S8252 has internal pull-ups on P1 (which includes MISO) all the time. They don't have to be enabled.

Also, can you try putting a 30pf Capacitor on the SCLK input of the AT89S8252.


In one of my iterations of tests I put a 100 ohm resistor from SCK to a 22pf capacitor and then to ground and that didn't seem to change anything. I could tie a 30pf capacitor directly between SCK and ground and try that if you think it'd make a difference.

Regards,
Craig Steiner


List of 26 messages in thread
TopicAuthorDate
AT89S8252 ISP via SPI            01/01/70 00:00      
   RE: AT89S8252 ISP via SPI            01/01/70 00:00      
      Alternative ISP software            01/01/70 00:00      
      RE: AT89S8252 ISP via SPI            01/01/70 00:00      
   RE: AT89S8252 ISP via SPI            01/01/70 00:00      
      RE: AT89S8252 ISP via SPI            01/01/70 00:00      
   RE: AT89S8252 ISP via SPI            01/01/70 00:00      
      RE: AT89S8252 ISP via SPI            01/01/70 00:00      
   RE: AT89S8252 ISP via SPI            01/01/70 00:00      
      Problem is on P1.6 (MISO)            01/01/70 00:00      
   RE: AT89S8252 ISP via SPI            01/01/70 00:00      
      RE: AT89S8252 ISP via SPI            01/01/70 00:00      
         Problem solved            01/01/70 00:00      
            Oops, credited wrong person            01/01/70 00:00      
   Correcting the SP89 schematic            01/01/70 00:00      
      Proven-Product Syndrome strikes again            01/01/70 00:00      
      RE: Correcting the SP89 schematic            01/01/70 00:00      
         RE: Correcting the SP89 schematic            01/01/70 00:00      
         RE: Correcting the SP89 schematic            01/01/70 00:00      
         RE: Correcting the SP89 schematic            01/01/70 00:00      
            RE: Correcting the SP89 schematic            01/01/70 00:00      
   Simplified and working schematic            01/01/70 00:00      
      RE: Simplified and working schematic            01/01/70 00:00      
         RE: Simplified and working schematic            01/01/70 00:00      
            RE: Simplified and working schematic            01/01/70 00:00      
               Working design            01/01/70 00:00      

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