Hi,

Well...I've been reading the datasheets a couple of time before sending
this mail. I must say that it hasn't made me any wiser.
My DS18S20 is used with +5, Gnd and signal so it should not be a need
for a strong pullup. And as I can read the ROM ID I know it's connected
correct.

This is my code for reading the temp. In this code I tried with pullup also.
As before all chars from DS2480B is read by the interrupt routine.

Have I missed something or should have done it some other way?

   putc(0x39); // pullup dur. 524ms
   putc(0xC1); // Reset
   putc(0xE1); // Data mode
   putc(0x55); // Match ROM
   putc(0x28); // ROM ID 0
   putc(0x53); // ROM ID 1
   putc(0x57); // ROM ID 2
   putc(0x2C); // ROM ID 3
   putc(0x00); // ROM ID 4
   putc(0x00); // ROM ID 5
   putc(0x00); // ROM ID 6
   putc(0xCF); // ROM ID 7
   putc(0xE3); // Set command mode
   putc(0xEF); // Arm pullup
   putc(0xF1); // Terminate puls
   putc(0xE1); // Set data mode
   putc(0x44); // Convert temperature
   delay_ms(1500);   // Allow conversion to finish
   putc(0xE3); // Command mode
   putc(0xED); // Disarm pullup
   putc(0xF1); // Terminate pulse
   putc(0xC1); // Reset

   delay_ms(100);   // Just a delay before next step

   putc(0xC1); // Reset
   putc(0xE1); // Data mode
   putc(0x55); // Match ROM
   putc(0x28); // ROM ID 0
   putc(0x53); // ROM ID 1
   putc(0x57); // ROM ID 2
   putc(0x2C); // ROM ID 3
   putc(0x00); // ROM ID 4
   putc(0x00); // ROM ID 5
   putc(0x00); // ROM ID 6
   putc(0xCF); // ROM ID 7
   putc(0xBE); // Read scratch pad
   putc(0xFF); // Read byte 0
   putc(0xFF); // Read byte 1
   putc(0xFF); // Read byte 2
   putc(0xFF); // Read byte 3
   putc(0xFF); // Read byte 4
   putc(0xFF); // Read byte 5
   putc(0xFF); // Read byte 6
   putc(0xFF); // Read byte 7
   putc(0xFF); // Read byte 8
   putc(0xE3); // Command mode
   putc(0xC1); // Reset

Well...panick is close...

Any help and ideas or corrections is VERY VERY much appreciated.


Best regards
Johan Fredriksson

JPF Consulting

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