Started by ikonsgr, 09:17, 01 December 20
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Quote from: eto on 12:26, 06 July 22Interesting: How can the ROM number have an effect on the compatibility, if there is no ROM number collision?
Quote from: Fran123 on 12:50, 06 July 22Quote from: eto on 12:26, 06 July 22Interesting: How can the ROM number have an effect on the compatibility, if there is no ROM number collision?I guess when you write a rsx command the system searches the command in the ROMs in a specific order, and when it finds out, it stops
Quote from: etoIs there a difference if the USIFAC physically before or after the Flash Gordon in the MX4?
Quote from: etoThat is true, but I understood that there is no other ROM present, the FlashGordon is just physically present.
Quote from: WacKEDmaN on 04:58, 07 July 22looks like my replica board is incompatible with the USIFAC IIive just finished testing it on an original 464...and it worked fine... (6e..without the diode! just the resistor..and with the same power supply)i also tested a DDI5 on the replica board and it works fine...there is something about the USIFAC II that the replica board really doesnt like is anyone using the USIFAC on a Version 1 board? (PT No 270100, MC0001A with slashed zeros?!...not the Z70100!) which my replica was based off..
Quote from: Devlin on 10:50, 07 July 22Version 1 yes, but mine is an OG Z70100 not the MC0001A
Quote from: ikonsgr on 12:17, 07 July 22Quote from: Devlin on 10:50, 07 July 22Version 1 yes, but mine is an OG Z70100 not the MC0001ASo, does USIfAC II works with your CPC464 replica?
Quote from: WacKEDmaN on 13:06, 07 July 22Quote from: ikonsgr on 12:17, 07 July 22Quote from: Devlin on 10:50, 07 July 22Version 1 yes, but mine is an OG Z70100 not the MC0001ASo, does USIfAC II works with your CPC464 replica?seems Devlin is using an original 464...not a replica and the Z70100 not the 270100 (mine has a 2 not a Z!) as can been seen on the mainboard versions page.. eghttps://www.cpcwiki.eu/imgs/c/ca/CPC464_270100_Grimware_crop.jpg <the board my replica is based offhttps://www.cpcwiki.eu/imgs/6/60/CPC464_Z70100_Tomdalby.jpg < Devlins board
Quote from: Devlin on 13:20, 07 July 22Yep, that's the one - although I believe mine is even slightly different to that, as mine has no components with that white tubing on it, and the heat-sink (now replaced) is a full square of metal with the wee tabs and no cut-outs on it.It might be worth prodding Bryce or someone in the know as to why it might be occurring.
Quote from: eto on 14:30, 07 July 22I guess it's save to say, that the USIFAC has issues with some 464s. It's totally unclear though, if there is a common factor behind it or if there are several issued that can cause this. I doubt it's just bad luck as I had 2 different 464s with exactly the same behaviour.If there is any way to help with debugging this, I would be happy to do so.
Quote from: WacKEDmaN on 15:56, 07 July 22im not sure where to go from here to debug it..
Quote from: WacKEDmaN on 15:56, 07 July 22when i use the 1.1 ROM (patched to show 64k on boot) with the usifac it will actually boot...BUT..the screen gets all screwed up (like the CRTC timings are being messed with).. it gets to Ready and cursor, but no ROM string, and trying to use the RSX commands, it will either just lock up or throw a few random pixels on the screen and then lockup!
Quote from: ikonsgr on 12:11, 08 July 22Well,i believe that the root of the problem might has to do with the handling of ready signal from USIfAC. When USIfAC is activated, a PIC's pin (the output of the master Configurable Logic Cell) goes to gnd, and through a diode to READY signal. This suppress the READY pulse from Gate Array chip, and practically freeze Amstrad, exactly like when you press the pause switch. This method seemed to work on all Amstrad CPC's i've tried (~10 different Amstrad's both CPC 6128 and CPC464), but for some reason it might not work on specific Amstrads. One thing i don't know for sure, is if USIfAC works ok with older 40007 GA chip, for example my CPC 464 has the newer 40010 chip installed, and a couple of other CPC464 i've tried i don't know what GA chip had.So, first, anyone with this kind of wierd erratic problems on CPC464, can check what GA chip is installed. Then,you might experiment with 10k pull-up or pull-down resistors on either READY signal (pins in green circle), or master CLC output (pins in Red circle). For a "deeper" analysis, if someone has an oscilloscope can check Amstrad's READY signal with USIfac on board.
Quote from: ikonsgr on 12:11, 08 July 22So, first, anyone with this kind of wierd erratic problems on CPC464, can check what GA chip is installed. Then,you might experiment with 10k pull-up or pull-down resistors on either READY signal (pins in green circle), or master CLC output (pins in Red circle).
Quote from: eto on 21:17, 08 July 22does the big red circle with the diode have a meaning for this task?
Quote from: eto on 13:09, 13 July 22I have just realised that there is now a diode but no longer the pull-up resistor. Should I remove the resistor and add the diode? Or does it depend on the firmware, which modification is required? The comments on the previous page are a bit confusing, and I would prefer to have the right modification applied before doing further tests. Maybe a suggestion: hardware modifications could be documented in the first post, like the firmware updates.
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