Search found 605 matches

by tcat
Mon May 18, 2020 6:32 am
Forum: General QL Chat
Topic: Custom QL Retrobrighting
Replies: 10
Views: 862

Re: Custom QL Retrobrighting

Hi,

Cool. Just wondering what is that brighting formula, something women use to dye their hair, that is peroxyde based paste? Unfortunately my missus uses mahagon colours. Not useful for my ATARI ST machine.

Tomas
by tcat
Thu Apr 16, 2020 8:22 am
Forum: Software & Programming
Topic: John Conway: Game Over
Replies: 18
Views: 1088

Re: John Conway: Game Over

Hi, Nice prog in commemoration of Conway. Over the summer I did some reading on `Surreal Numbers' (only half understood), a new maths apparently also founded by Conway. The theory further leads to `Strategy Games', with interesting property, that for some games a winning strategy exists in the domai...
by tcat
Wed Apr 08, 2020 7:07 am
Forum: Software & Programming
Topic: Digital C SE Foibles on QPC2
Replies: 16
Views: 842

Re: Digital C SE Foibles on QPC2

Hi,

I have not used `DC' compiler on QL yet. I was once toying with `GST C' (integer compiler too) but not beyond examples. How do these two compare?

I regularly use `qdos-gcc' though on linux. There is also `EasyC' found on `QPTR COMPANION` disk, that I have not tried either.

Tomas
by tcat
Tue Mar 31, 2020 9:45 am
Forum: Hardware
Topic: QL Add-on ROM
Replies: 34
Views: 1781

Re: QL Add-on ROM

Hi, All the SRAM backed protection, makes me thinking about mechanical bank switching on 512K eeprom, as I can address only 256K upper or lower halves. Here I rely that a reverse leakage is big enough to pull address line high, and not that big to be pulled low with a switch. I know resistors could ...
by tcat
Mon Mar 30, 2020 7:43 pm
Forum: Hardware
Topic: QL Add-on ROM
Replies: 34
Views: 1781

Re: QL Add-on ROM

Hi Dave,

I see your point, battery backed SRAM, similar to what Martin has proposed. This flip-flop is a write-protection trigger, right? As I believe just to write enable, SDWL signal should suffice or not?

Many thanks for taking your interest.
Tomas
by tcat
Sun Mar 29, 2020 5:06 pm
Forum: Hardware
Topic: QL Add-on ROM
Replies: 34
Views: 1781

Re: QL Add-on ROM

Hi, Thinking further. On AM29F040 /OE seems complementing /WE as per the specs. While CPU R/W (RDWL) could wire directly to /WE, /OE needs to be inverted. This may require extra RW GAL input, correct, could this work? VALID_ROM = A19 * A18 # $C0000 ROM_CE = VALID_ROM * DS IF( VALID_ROM ) DSMCL = 1 I...
by tcat
Sun Mar 29, 2020 9:26 am
Forum: Hardware
Topic: QL Add-on ROM
Replies: 34
Views: 1781

Re: QL Add-on ROM

Hi All, Many thanks for useful arguments. I wish to explore in theory, what I could do with `29F040', fitted in a daughter board above `Simple RAM' based on `AS6C4008', if proved possible to program right on QL bus. It should serve primarily as read only media, holding extensions mentioned earlier. ...
by tcat
Sat Mar 28, 2020 10:18 am
Forum: Hardware
Topic: QL Add-on ROM
Replies: 34
Views: 1781

Re: QL Add-on ROM

Hi, Yes, EDIT preprogramming the flash outside the QL machine, seems easiest. To act as a ROM inside QL, /WE is then fix wired to be kept high. I have seen various circuits on the net, that use a diode (IN4148), probably to pull signal high or low, or initiate some delay on power on. Still do not ge...
by tcat
Fri Mar 27, 2020 3:23 pm
Forum: Hardware
Topic: QL Add-on ROM
Replies: 34
Views: 1781

Re: QL Add-on ROM

Hi, Thank you. I will probably go with $C0000 address decode, as I do not have wired A17 line, so it may be easier, also this way I could use up to half of the EEPROM capacity 256K. In the glue logic, I drive both RAM /OE and /CS with GAL's /RAMCE pin. CPU R/W is connected directly to RAM /WE. I am ...
by tcat
Thu Mar 26, 2020 8:16 am
Forum: Hardware
Topic: QL Add-on ROM
Replies: 34
Views: 1781

Re: QL Add-on ROM

Hi, Thanks for all the input, digesting (1 of 100% complete). I am also thinking of `venturing' something simple of my own, me capable of. Looking back at `Simple RAM' these are GAL equations, I pulled together with the help in the forum here. GAL16V8 Glue logic for 512x8 SRAM Sinclair QL RAM Expans...