TFMSX rev1
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TFMSX rev1
It’s here and booting… it did not work with the V9958 chip I had so I had to desolder a 9938 from a Rev0
———
"It is not necessarily a supply voltage at no load, but the amount of current it can provide when touched that
indicates how much hurting you shall receive."
"It is not necessarily a supply voltage at no load, but the amount of current it can provide when touched that
indicates how much hurting you shall receive."
- stephen_usher
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Re: TFMSX rev1
Any clues as to why it wouldn't work with the V9958? Timing?
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
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Re: TFMSX rev1
I've really not dug into it yet. I could be as simple as my 9958 chip is dead. I have no way to verify.
———
"It is not necessarily a supply voltage at no load, but the amount of current it can provide when touched that
indicates how much hurting you shall receive."
"It is not necessarily a supply voltage at no load, but the amount of current it can provide when touched that
indicates how much hurting you shall receive."
- arkadiusz.makarenko
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Re: TFMSX rev1
This board is tiny!
Do not trust people. They are capable of greatness.
~ Stanislaw Lem
~ Stanislaw Lem
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Re: TFMSX rev1
Yeah. I am waiting for VDP chip and i'll make you up a board. I've reclaimed some ARM Chips hope they work. Also these boards have 288 CPLDs on them because thats what i have spare. But they should manage to work with a 144 for "Production"
———
"It is not necessarily a supply voltage at no load, but the amount of current it can provide when touched that
indicates how much hurting you shall receive."
"It is not necessarily a supply voltage at no load, but the amount of current it can provide when touched that
indicates how much hurting you shall receive."
- arkadiusz.makarenko
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Re: TFMSX rev1
I will prepare initial firmware for f722 as I have few of them just now. But for production I will downgrade it to f730, as it is few £ cheaper and usually* more available. Unless more flash and sram would be somehow useful.
* chip shortage changed that, hopefully temporarily.
Ps
Do you have gerbers for that cart pcb or dod you buy it somewhere (local)?
* chip shortage changed that, hopefully temporarily.
Ps
Do you have gerbers for that cart pcb or dod you buy it somewhere (local)?
Do not trust people. They are capable of greatness.
~ Stanislaw Lem
~ Stanislaw Lem
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Re: TFMSX rev1
Ah that cart was supplied by BanjoGuyOllie.arkadiusz.makarenko wrote: ↑Wed Oct 20, 2021 12:36 pm I will prepare initial firmware for f722 as I have few of them just now. But for production I will downgrade it to f730, as it is few £ cheaper and usually* more available. Unless more flash and sram would be somehow useful.
* chip shortage changed that, hopefully temporarily.
Ps
Do you have gerbers for that cart pcb or dod you buy it somewhere (local)?
https://www.etsy.com/uk/listing/7078448 ... ve_4&crt=1
Not expensive really.
EDIT: Also yes.. Whichever arm can do the job and is cheaper lets go with.
———
"It is not necessarily a supply voltage at no load, but the amount of current it can provide when touched that
indicates how much hurting you shall receive."
"It is not necessarily a supply voltage at no load, but the amount of current it can provide when touched that
indicates how much hurting you shall receive."
Re: TFMSX rev1
Cool... looking forward to this.
There are some slight differences between 9938/9958, main 3 are:
Pin 21 - V9938 uses this pin as composite video output, V9958 uses it as power supply for video DAC.
Pin 26 - V9938 can use this pin as a light pen switch input. V9958 uses it as /WAIT signal to CPU.
Pin 5/6 - Both V9938 and V9958 use this as H/CSYNC voltage levels are different.
Also pin 4,8, and 27 have been modified, see page 12 of the 9958 technical manual:
https://retrobrewcomputers.org/n8vem-pb ... asheet.pdf
There are some slight differences between 9938/9958, main 3 are:
Pin 21 - V9938 uses this pin as composite video output, V9958 uses it as power supply for video DAC.
Pin 26 - V9938 can use this pin as a light pen switch input. V9958 uses it as /WAIT signal to CPU.
Pin 5/6 - Both V9938 and V9958 use this as H/CSYNC voltage levels are different.
Also pin 4,8, and 27 have been modified, see page 12 of the 9958 technical manual:
https://retrobrewcomputers.org/n8vem-pb ... asheet.pdf
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Re: TFMSX rev1
OK i have:-Gooeyblob wrote: ↑Wed Oct 20, 2021 6:35 pm Cool... looking forward to this.
There are some slight differences between 9938/9958, main 3 are:
Pin 21 - V9938 uses this pin as composite video output, V9958 uses it as power supply for video DAC.
Pin 26 - V9938 can use this pin as a light pen switch input. V9958 uses it as /WAIT signal to CPU.
Pin 5/6 - Both V9938 and V9958 use this as H/CSYNC voltage levels are different.
Also pin 4,8, and 27 have been modified, see page 12 of the 9958 technical manual:
https://retrobrewcomputers.org/n8vem-pb ... asheet.pdf
pin 21 NC. (could be the reason no output)
pin 26 is tied to VCC.
5/6 are the syncs. I am getting sync signals .. just no video.
pin 4 is NC its some kind of reset in. The manual says it will float.
pin 8 i have the CPU clock connected as an input... this may be wrong. I need to check 9938 behaviour.
pin 27 is tied to VCC.
These are branded as drop in replacements.. :/
EDIT: well that was useful. pin 8 is an output on both chips. I should remove the inline resistor and that will solve the problem.
———
"It is not necessarily a supply voltage at no load, but the amount of current it can provide when touched that
indicates how much hurting you shall receive."
"It is not necessarily a supply voltage at no load, but the amount of current it can provide when touched that
indicates how much hurting you shall receive."
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- Joined: Mon Aug 28, 2017 10:56 pm
- Location: Glasgow, UK
Re: TFMSX rev1
Ok i have the 9958 working fine. I noticed i'm not doing a long enough POR either so i'll see if i can sort that in the CPLD
Adjustment of the POR time fixed my power on sometimes not working thing.
Adjustment of the POR time fixed my power on sometimes not working thing.
———
"It is not necessarily a supply voltage at no load, but the amount of current it can provide when touched that
indicates how much hurting you shall receive."
"It is not necessarily a supply voltage at no load, but the amount of current it can provide when touched that
indicates how much hurting you shall receive."