Re: ROM Dump of Amiga Keyboard controller

On 7/1/2014 12:18 PM, Gerrit Heitsch wrote:
>
> You made sure you supplied the bytes at half the speed of the clock 
> you supplied to the 6500/1? Then there is, of course the question of 
> phase. Since the external clock is divided by 2, there are 2 possible 
> phases for the resulting clock signal the CPU runs on.
Yes, each byte send requires 4 CLK transitions (high,low,high,low). I 
synchronized the phase by sending data during the reset phase, to keep 
timing.
> So my idea is to get the external clock stable while keeping _RESET 
> low, then have it go to +5V for a moment before going to +10V and 
> start supplying the byte sequence.
I went from RESET to TEST, but can try doing 5V for a bit and then doing 
TEST.  Right now, I have:


static inline __attribute__((always_inline)) void send_data(uint8_t data) {
   PORTC = data;

   while(!(TIFR & _BV(OCF2))); // went high
   TIFR |= _BV(OCF2);
   while(!(TIFR & _BV(OCF2))); // went lo
   TIFR |= _BV(OCF2);
   while(!(TIFR & _BV(OCF2))); // went hi
   TIFR |= _BV(OCF2);
   while(!(TIFR & _BV(OCF2))); // went lo
   TIFR |= _BV(OCF2);
}


   RESET_ON();
   send_data(0xEA);
   send_data(0xEA);
   send_data(0xEA);
   send_data(0xEA);
   send_data(0xEA);
   send_data(0xEA);
   send_data(0xEA);
   send_data(0xEA);
   send_data(0xEA);
   send_data(0xEA);
   send_data(0xEA);
   send_data(0xEA);
   send_data(0xEA);
   send_data(0xEA);
   send_data(0xEA);
   send_data(0xEA);
   send_data(0xEA);
   send_data(0xEA);
   send_data(0xEA);
   send_data(0xEA);
   TEST_ON();
send_data(0xEA);
     send_data(0xEA);
     send_data(0xEA);
     send_data(0xEA);
     send_data(0xEA);
     send_data(0xEA);
     send_data(0xEA);
     send_data(0xEA);
     send_data(0xEA);
     send_data(0xEA);
     send_data(0x2C);
     send_data(0x24);
     send_data(0xEA);
     send_data(0xEA);
     send_data(0x78);
     send_data(0x78);
     send_data(0xA9);
     send_data(0x55);
     send_data(0x85);
     send_data(0x83);
     read_data();
     send_data(0x02);

I put all of this in a loop, so I can keep trying...


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