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GeneralRe: Question for you electronic DIY people Pin
Peter Shaw25-Feb-19 2:46
professionalPeter Shaw25-Feb-19 2:46 
GeneralRe: Question for you electronic DIY people Pin
Tiger1250619-Feb-19 3:04
Tiger1250619-Feb-19 3:04 
GeneralRe: Question for you electronic DIY people Pin
OriginalGriff18-Feb-19 4:36
mveOriginalGriff18-Feb-19 4:36 
GeneralRe: Question for you electronic DIY people Pin
den2k8818-Feb-19 4:49
professionalden2k8818-Feb-19 4:49 
GeneralRe: Question for you electronic DIY people Pin
Peter Shaw25-Feb-19 2:40
professionalPeter Shaw25-Feb-19 2:40 
GeneralRe: Question for you electronic DIY people Pin
CodeWraith25-Feb-19 3:29
CodeWraith25-Feb-19 3:29 
GeneralRe: Question for you electronic DIY people Pin
Peter Shaw25-Feb-19 4:06
professionalPeter Shaw25-Feb-19 4:06 
GeneralRe: Question for you electronic DIY people Pin
CodeWraith25-Feb-19 4:51
CodeWraith25-Feb-19 4:51 
Peter Shaw wrote:
I basically got a tube (25) of PIC16F54's and then proceeded to program them as CMOS/Discrete logic.
That's exactly the idea. These are the things I am sure to know how to pull them off:

- Processor clock and mode control, plus reading programs from a serial ROM and loading them into RAM by DMA. This eliminates the need for any ROM in the memory map, allows bootloading and also allows to stay compatible to the old designs which had a front panel with switches and LED displays to enter code by DMA.

- An interrupt controller. The 'official' interrupt controller takes up too much memory space or too many I/O ports with its numerous registers and awkward addressing if memory mapped.

- PS/2 keyboard aand mouse ports. I would not know where to get an oldschool parallel Keyboard these days.

- The front panel I mentioned before: Both hexadecimal keyboard encoders and hex seven segment drivers are long out of production. Both jobs can easily be done by PICs.

Here some stuff I don't have figured out yet:

- A standard IDE interface is basically just a fancy parallel port. I have a 82C55 here, which would do the trick, but a PIC could be faster. The only thing that I have not figured out yet is how to communicate with the main processor. Even a PIC with a PSP does not appear to be up to the job.

- A 'MMU' that allows me to extend the address bus to 24 bits and fetch any byte from up to 16Mb RAM quickly enough. Here the PSP is again too limited. I need three 'registers' for the address extension of three banks and of course I need to read and write bytes to memory, all over that PSP. Also, I doubt that a PIC can easily do the job within the main processor's bus cycles. At 20 MHz it could only execute one instruction per clock pulse of the main processor. It would only have four or perhaps five instructions to do its addressing. Not enough, unless I slow down the main processor.
I have lived with several Zen masters - all of them were cats.

His last invention was an evil Lasagna. It didn't kill anyone, and it actually tasted pretty good.

GeneralRe: Question for you electronic DIY people Pin
markkuk18-Feb-19 1:33
markkuk18-Feb-19 1:33 
GeneralRe: Question for you electronic DIY people Pin
den2k8818-Feb-19 4:31
professionalden2k8818-Feb-19 4:31 
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Mark_Wallace18-Feb-19 9:38
Mark_Wallace18-Feb-19 9:38 
GeneralRe: Question for you electronic DIY people Pin
Clumpco18-Feb-19 22:15
Clumpco18-Feb-19 22:15 
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den2k8818-Feb-19 23:36
professionalden2k8818-Feb-19 23:36 
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L. Braun18-Feb-19 22:47
L. Braun18-Feb-19 22:47 
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den2k8818-Feb-19 23:37
professionalden2k8818-Feb-19 23:37 
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Slow Eddie19-Feb-19 3:56
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den2k8819-Feb-19 21:29
professionalden2k8819-Feb-19 21:29 
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Slow Eddie20-Feb-19 3:20
professionalSlow Eddie20-Feb-19 3:20 
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MSBassSinger19-Feb-19 5:16
professionalMSBassSinger19-Feb-19 5:16 
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sasadler19-Feb-19 5:50
sasadler19-Feb-19 5:50 
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jeb121719-Feb-19 6:13
professionaljeb121719-Feb-19 6:13 
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den2k8819-Feb-19 21:28
professionalden2k8819-Feb-19 21:28 
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Peter Shaw25-Feb-19 2:53
professionalPeter Shaw25-Feb-19 2:53 
GeneralI hate that... Pin
OriginalGriff17-Feb-19 23:16
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Daniel Pfeffer17-Feb-19 23:22
professionalDaniel Pfeffer17-Feb-19 23:22 

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