Quote:
Originally Posted by SpeedGeek
@pandy71
If the host Amiga has a motherboard 68000 present (i.e. A500,A2000) you don't need to worry about E clock. The 68000 continues to output the E clock even when another CPU masters the bus. Gayle and Fat Gary generate E clock on Amigas without a motherboard 68000.
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Nope - E clock is 1/10 asynchronous clock generated in 68000 in a kind of ring counter - for 8MHz it is around 0.8MHz - CIA works correctly but for 16MHz it will be 1.6MHz, CIA will work twice fast or not work at all (but anyway all timing related to CIA will be wrong).
A600 not use E clock from CPU but from Gayle - for any accelerator for Amiga
without Gayle or similar function, E clock must be generated externally and all bus timing related to VPA IC's implemented by DTACK.
BTW
MC68000 accel board can be usefulldue of simplicity - 68020 need more complicated board - twice as in 68000 case number of DATA lines make PCB more complicated - 68000 PCB can be made in home with iron on 2 layers, 68020 probably need 4 layer PCB ie at start it is more serious project.