silverfox0786
Beware the Hillman
Hurray Banana said:
yes i am making the PODS with the extra circuit to to the VRAM writes and will chat to Mark later tonight about what to do about the Anylizer
PI/Arduino Processor Emulator
- Thread starter andrewsm
- Start date
yes i am making the PODS with the extra circuit to to the VRAM writes and will chat to Mark later tonight about what to do about the Anylizer
The Last Bandit
User
Are these CPU pods not included with the AR81 ?
Hi. Just in and seen these posts.
All the changes I have made can be retrofitted to existing testers. The new motherboards (which I needed to do anyhow) will include these changes as standard.
The VRAM write can be added on by using Sarj's adapter board or I can give details of the additional hardware wif you want to make it yourself.
The Logic analyser is a software update which can be loaded into the existing testers. It will support 8 channels however the existing tester will support 1 channel on the probe. If the other 7 channels are required, then some wires will have to be added and a connector as the existing motherboards dont have the pins connected to the outside world. Again I can give details on this if needed.
I am trying to improve and add to the testers all the time but also I am bearing in mind there will be existing testers out there so any changes will be made to work on both.
There might be a slight increase in cost due to a few additional parts but thats it really.
The CPU pods are not included but wiring details are in the manual so it is an easy thing to do. Reason I didnt include was because there are currently 3 CPUS supported so it would add a bit extra by making up all pods when only one may be required at first.
Hope this helps
Mark
andrewsm2016-09-19 15:15:47
All the changes I have made can be retrofitted to existing testers. The new motherboards (which I needed to do anyhow) will include these changes as standard.
The VRAM write can be added on by using Sarj's adapter board or I can give details of the additional hardware wif you want to make it yourself.
The Logic analyser is a software update which can be loaded into the existing testers. It will support 8 channels however the existing tester will support 1 channel on the probe. If the other 7 channels are required, then some wires will have to be added and a connector as the existing motherboards dont have the pins connected to the outside world. Again I can give details on this if needed.
I am trying to improve and add to the testers all the time but also I am bearing in mind there will be existing testers out there so any changes will be made to work on both.
There might be a slight increase in cost due to a few additional parts but thats it really.
The CPU pods are not included but wiring details are in the manual so it is an easy thing to do. Reason I didnt include was because there are currently 3 CPUS supported so it would add a bit extra by making up all pods when only one may be required at first.
Hope this helps
Mark
andrewsm2016-09-19 15:15:47
Cheers mark and sarj. I need to catch up with this when i get time. Ill probably buy all the extension hardware for this
Thought a little bit more info on the VRAM mod might be in order guys.
Right from the start the tester has been able to read roms without issues as the data is presented on the bus once various control signals have been asserted. To read and write to VRAM is more tricky since the ram is shared with video circuitry and hence can only be accessed in a brief window when usually the vblank is done.
I found after much head scratching that the arduino just isnt fast enough to detect the window and also process the data so random results were returned. Check out Paul Swans posts as I think hes had same issues.
Anyhow, after a lot of work, I have managed to sort it out but i had to add a little hardware that is now controlled by the clock signal. Its been working fine with a Z80 system. The software is still much the same except Ive optimised it so data is read and written faster but the hardware (3 chips) takes care of the data in the window). Using this method means that the data presented to the tester is now always stable and hence read correctly. The timings were approx 320nS pulses and the arduino will only manage 690nS approx.
The mods can be added to the signals going to the tester so Sarj's adapter board is ideal for it. On another side of this, the data bus is now buffered so if u blow up anything, it will be the buffers now rather than the arduino!
Hope this helps clear up things a bit. As I said from the start this project is getting improved all the time.
Right from the start the tester has been able to read roms without issues as the data is presented on the bus once various control signals have been asserted. To read and write to VRAM is more tricky since the ram is shared with video circuitry and hence can only be accessed in a brief window when usually the vblank is done.
I found after much head scratching that the arduino just isnt fast enough to detect the window and also process the data so random results were returned. Check out Paul Swans posts as I think hes had same issues.
Anyhow, after a lot of work, I have managed to sort it out but i had to add a little hardware that is now controlled by the clock signal. Its been working fine with a Z80 system. The software is still much the same except Ive optimised it so data is read and written faster but the hardware (3 chips) takes care of the data in the window). Using this method means that the data presented to the tester is now always stable and hence read correctly. The timings were approx 320nS pulses and the arduino will only manage 690nS approx.
The mods can be added to the signals going to the tester so Sarj's adapter board is ideal for it. On another side of this, the data bus is now buffered so if u blow up anything, it will be the buffers now rather than the arduino!
Hope this helps clear up things a bit. As I said from the start this project is getting improved all the time.
Mark, you can get away without any external circuitry for the VRAM access with optimization of the port pin layouts to port-byte-align the address & data bus, and use one byte port for critical inputs and another byte port for the critical outputs. This is the implementation for mine:-
https://github.com/prswan/arduino-mega-ict/blob/8080/libraries/C8080Cpu/C8080DedicatedCpu.cpp
Paul.
https://github.com/prswan/arduino-mega-ict/blob/8080/libraries/C8080Cpu/C8080DedicatedCpu.cpp
Paul.
The Last Bandit
User
Using the Arduino digitalRead & digitalWrite functions are very slow compared accessing the using the native AVR LibC.
Depending on where you look but digitalWrite is anywhere between 10x and 20x times slower than writing directly to the PIN/PORT, so ya byte/port alignment should definitely improving the read/write access times.
Depending on where you look but digitalWrite is anywhere between 10x and 20x times slower than writing directly to the PIN/PORT, so ya byte/port alignment should definitely improving the read/write access times.
Thanks Paul I will take a look and PM u on this mate. I found out that digitalRead etc is slow so I already use PORTs. I still had trouble but it might be the pin mappings Ive done. The hardware works well and takes the pressure off the arduino in timings but if I can use software then great.
Just been reading through http://www.arcadetester.co.uk, all very well written though I think some be bits will make more sense to me when I have a tester here. Will the mod for for the 8 channel logic analyser be added on the site? From what I understand it's just wires from the main board, are there good solder pads to be able to add this easily?andrewsm said:
Thanks
silverfox0786
Beware the Hillman
radfoo said:
yes it will be added, i'm just awaiting andrewsm to send me the details of the addition and ill add for you guys to do yourself
Hey Mark, you mentioned you may be working on 2716 eeprom burning; is that going to be a feature?
Eeprom burning in general is great but covering the older stuff would really make this exceptional. This is becoming an essential piece of kit!
Eeprom burning in general is great but covering the older stuff would really make this exceptional. This is becoming an essential piece of kit!
david_orton_2000
Green Mario
This project is a tester/de-bugger,/analyser...I would not really say for Eprom burning, especially as 2716 require 25V to program. Better Eprom programmers do that separately. 
Also, as an aside beware of differences with 2716s!
http://www.tomshardware.co.uk/forum/80532-13-what-diff-eprom-eprom
Also, as an aside beware of differences with 2716s!
http://www.tomshardware.co.uk/forum/80532-13-what-diff-eprom-eprom
Hey, sorry been working on building testers etc.
Yes I am planning an add on board which will program 2716, 2708 and other eproms. I already have an idea how Im going to do it and it's something I want myself.
Im aware of differences so there will be a file for each type of eprom which will allow full control of the voltages times etc.
The tester is more than capable of doing this so will be an optional extra once I get more time to work on it.
Im also currently uploading two more videos on the Youtube channel showing the tester checking 2114 RAM chips on a duff pacman board. It was a working pacman but since I messed with it... well enough said!
I agree there are loads of great programmers out there and Im not trying to compete with these by any means. My goal is to provide a decent programmer which will handle the older obsolete stuff mainly. Yes it will need a complex triple rail supply but aiming to make it a simple board so its just plugged into the tester and thats it. Its just a rough design atm as a few issues need to be resolved.
Simply trying to make this tester be as versatile as possible.
andrewsm2016-09-26 21:12:36
Yes I am planning an add on board which will program 2716, 2708 and other eproms. I already have an idea how Im going to do it and it's something I want myself.
Im aware of differences so there will be a file for each type of eprom which will allow full control of the voltages times etc.
The tester is more than capable of doing this so will be an optional extra once I get more time to work on it.
Im also currently uploading two more videos on the Youtube channel showing the tester checking 2114 RAM chips on a duff pacman board. It was a working pacman but since I messed with it... well enough said!
I agree there are loads of great programmers out there and Im not trying to compete with these by any means. My goal is to provide a decent programmer which will handle the older obsolete stuff mainly. Yes it will need a complex triple rail supply but aiming to make it a simple board so its just plugged into the tester and thats it. Its just a rough design atm as a few issues need to be resolved.
Simply trying to make this tester be as versatile as possible.
andrewsm2016-09-26 21:12:36
Nice Mark, When I get the chance I can try to use this to resurrect one of my pac boards