Plan to used for : I have a couple of Tektronix bench devices and an HP Logic analyzer to play with. All from the same era as the Macintosh.
So I just got all the parts to start the prototype and by accident I found a tech article by Apple [Technote HW 07] on the internet saying you should only use CMOS devices on a PDS for the LC or you can get bus errors.
So the uPd7210 is pure NMOS, adding a CMOS buffer would fix it but will make timing more complex.
A possible solution would be to use the TMS9914A, need to check if I can find some stock of it.
I'm struggling to write code, possible because I'm totally new to the Macintosh and could use some help.
First I used Chipmunk Basic peek/poke function to access any I/O registers, but I only get illegal instruction errors or basic crashes ...
So now I installed Think C (only works in 32bit mode), does anyone have some example code (C, pascal or ASM) how to read / write
I/O registers of the chips (for example the VIA) ?
PS : it's known that the LC and LC II are limited in speed because they 'only' access the RAM in 16 bits.
What if you add 32bits SRAM on the PDS card, can you make the OS use it without the memory controller controlling it.
This last is important so it want generate 16 bits memory acknowledge for it.
So I just got all the parts to start the prototype and by accident I found a tech article by Apple [Technote HW 07] on the internet saying you should only use CMOS devices on a PDS for the LC or you can get bus errors.
So the uPd7210 is pure NMOS, adding a CMOS buffer would fix it but will make timing more complex.
A possible solution would be to use the TMS9914A, need to check if I can find some stock of it.
I'm struggling to write code, possible because I'm totally new to the Macintosh and could use some help.
First I used Chipmunk Basic peek/poke function to access any I/O registers, but I only get illegal instruction errors or basic crashes ...
So now I installed Think C (only works in 32bit mode), does anyone have some example code (C, pascal or ASM) how to read / write
I/O registers of the chips (for example the VIA) ?
PS : it's known that the LC and LC II are limited in speed because they 'only' access the RAM in 16 bits.
What if you add 32bits SRAM on the PDS card, can you make the OS use it without the memory controller controlling it.
This last is important so it want generate 16 bits memory acknowledge for it.
