Recently i purchased a 512KB CST Rom Plus card. I want to ask which eprom programs i can burn to populate the four empty rom sockets.
Secondly, i assemble a CST QDISC v4 floppy disc controller, but it is not recognized on boot screen(green letters on upper part of screen "CST 1.18" etc..).
I replaced all 74LS ics, used a wd1772 instead of 1770, burned two more different firmwares on eproms, replaced 8Mhz XTAL, tested continuity from component to solder side vias, with no avail. Any ideas for further testing?
If indeed the v4 board uses the 'scrambled' method for data and/or address lines and if the ROM was programmed in a std programmer from a straight image, then therein would certainly lie one probable cause...
A quick check would be to PEEK_W from Basic the base address where the CST ROM is expected to lie in the memory map (0x0c000 is the first likely location) and check the returned word value, which should be the QDOS ROM flag (0x4afb, if I remember correctly.)
If it's not that, QDOS will skip that 16kB block and look elsewhere.
Then compare that against the first word of the original ROM image.
Again, the above assumes that the EPROM was programmed from a provided image as part of the self-build...
The transistor, chinesse ones are slow or something and got no boot message of the card.
Also 74ls04 chinesse for the oscilator cause me problems, in this case you got boot message but not recognice the board (the board shall show boot message even without wd177x
And you shall use a 27F128, for example, if you use a EEPROM W27C512, remember that you need to Burn It 4 times, or at least in the last 16kb of the chip, because the interface only use the last 16kb o f the 64 that has a W27C512.
You shall use the file CSTQD118.ROM the other one , unscramble, not work on the interfaz
Hello again!
I populated the CST Ram Plus card and i have some questions. I used 2N2222A instead of MPS2369. Both are NPN transistors and from the datasheets they seem to be interchangeable? Second, at the block diagram the lower right resistor is a 47KΩ or a 4.7KΩ resistor? And final, all eproms are indicated as 27256 on diagram. 27128 are not recommended?
@dilwyn
thanks for the manual.
@Pr0f
that is what i think, TK2, ICE, maybe 68K/OS, or programming languages that were partially on rom cartridge.
@Chris_68
The v1.18 bin file is a 16KB file if a remember correct. I burned two other 27C128 eproms and i am sure one file was 8KB and wrote it twice, on lower and upper bank but using first the HxD editor for doubling it.
@ones' complement
unfortunately i don't have a logic probe
@martyn_hill
and i am almost sure that i programmed the unscrambled v1.18 image.
@aalea About 2N2222A transistor, i don't know if it is a chinese the ones i have, but i used both plastic and metal case transistors with no luck.
I thought that maybe the problem has to do with the oscillator circuit, but i replaced all the XTAL parts and nothing changed.
I checked the eprom ics and the type is M27128AFI. I think it is ok.
I am quite sure that i programmed the eprom with the unscrambled file. And if the interface works correct with the CSTQD118.ROM, then that is the issue!
After the Orthodox Easter, i will program an eprom with the CSTQD118.ROM scrambled file and i'll come back for feedback.
I think the eprom sockets decode out as 32K chunks - so you can get 2 16K ROM images per 27256 Eprom.
Not sure you'd be able to get ICE to work - I am sure I've read somewhere that it expects to be at 0C000 (ROM Socket) in the QL memory map and may not work if located elsewhere.
Pr0f wrote: ↑Fri May 03, 2024 6:23 pm
I think the eprom sockets decode out as 32K chunks - so you can get 2 16K ROM images per 27256 Eprom.
Not sure you'd be able to get ICE to work - I am sure I've read somewhere that it expects to be at 0C000 (ROM Socket) in the QL memory map and may not work if located elsewhere.
I have disassembled ICE rom, just tryingbto understand the assembler source code.
I did think about writing a PTR_GEN driver for the ICE mouse or is that Mice ...
