Search found 34 matches

by lliont
Sat Aug 06, 2022 7:47 am
Forum: Hardware
Topic: CPLD replacement for ZX8301
Replies: 49
Views: 3389

Re: CPLD replacement for ZX8301

The EPM7128S that is cheap and available works also with the new pcb and 30Mhz osc. as I wrote with the difference that it flashes the complemented colors instead of the background and this due to resources limitation because there is no room in the cpld to save the background color data. This produ...
by lliont
Sat Aug 06, 2022 12:50 am
Forum: Hardware
Topic: CPLD replacement for ZX8301
Replies: 49
Views: 3389

Re: CPLD replacement for ZX8301

I got the EPM7160S and the 30Mhz smd oscillator and tested it with the new pcb and works OK and with the correct flash bit behavior. It also outputs the flash bit as a signal for any alternative use, when this output is enabled the flashing is disabled. With a simple resistor dac this could be used ...
by lliont
Mon Jul 11, 2022 1:38 pm
Forum: Hardware
Topic: CPLD replacement for ZX8301
Replies: 49
Views: 3389

Re: CPLD replacement for ZX8301

New pcb with video buffer arrived and tested OK. I tested it with the smaller cpld and a 15Mhz oscillator but in the final version I'll use a 30Mhz oscillator. So I'm waiting for 2 parts to have the 2 different versions of the ULA replacement board ready. -One with the EPM7128S with the only differe...
by lliont
Sat Jul 02, 2022 1:01 pm
Forum: Hardware
Topic: CPLD replacement for ZX8301
Replies: 49
Views: 3389

Re: CPLD replacement for ZX8301

Nasta wrote:Checked, mine is the old CLA2310 in a ceramic case, so perhaps one of the first ones...


So from CLA2310 to CLA2345 they maybe made some improvements. And to find out one with a CLA2310 on a standard QL could run the simple basic program and time it, CLA2345 takes about 51.5 secs.
by lliont
Fri Jul 01, 2022 11:04 pm
Forum: Hardware
Topic: CPLD replacement for ZX8301
Replies: 49
Views: 3389

Re: CPLD replacement for ZX8301

Cannot make heads nor tails of the speed difference you report. Are they as consistent as you say? As far as I know there are only two revisions, the old CLA2310 and the later CLA2345 which added NTFS support. I time the two by hand with my phone's stopwatch so it is not an accurate measurement, bu...
by lliont
Wed Jun 29, 2022 2:31 am
Forum: Hardware
Topic: CPLD replacement for ZX8301
Replies: 49
Views: 3389

Re: CPLD replacement for ZX8301

The simple basic program does a lot of printing and scrolling so it was a quick way to compare. I did the real test and it seems to work well without any refresh at the non-visible lines but of course that was only an experiment. All the times I listed are with the safe but optimized refresh. What d...
by lliont
Wed Jun 29, 2022 12:08 am
Forum: Hardware
Topic: CPLD replacement for ZX8301
Replies: 49
Views: 3389

Re: CPLD replacement for ZX8301

The same tests without the memory upgrade so that the basic code and variables are in the lower ram that the cpld manages give these results: Fast ULA 51.5 CPLD 50.9 Cpld is about 1.2% faster than the fast ULA, but the ram access speed improvement percentage is bigger because basic interpreter code ...
by lliont
Tue Jun 28, 2022 10:35 pm
Forum: Hardware
Topic: CPLD replacement for ZX8301
Replies: 49
Views: 3389

Re: CPLD replacement for ZX8301

What do the letters 'A' and 'E' indicate ?

A is on the fast
E is on the slower
by lliont
Tue Jun 28, 2022 5:48 pm
Forum: Hardware
Topic: CPLD replacement for ZX8301
Replies: 49
Views: 3389

Re: CPLD replacement for ZX8301

ones' complement wrote:How odd, almost looks like some revision happened in early November 1985 (8544 to 8546) :?


The older ULA is the fast :)
by lliont
Tue Jun 28, 2022 1:58 am
Forum: Hardware
Topic: CPLD replacement for ZX8301
Replies: 49
Views: 3389

Re: CPLD replacement for ZX8301

Well it is strange but the ULA seems to do optimized refresh at the non visible lines or the optimizations don't have a big effect on the speed for the test I run. I did the same and got about the same speed as the ULA only slightly faster. My QL memories from the factory are TMS4164-12 that have 4m...