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H4 schematic

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DoG
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Re: H4 schematic

Post by DoG »

Yeah. I already checked the schematics on the original ST but I didn't really get how to use it but now I know that it is possible at least. :D :roll: I think that if we can avoid doing skyscraper builds like the ones on the alpha board, we should avoid it. But good to know! I think I have to feed Harry and you can put in some extra stuff in my Mongrel Board order then....
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derkom
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Re: H4 schematic

Post by derkom »

Going over the v3 BOM to figure out what last components I might need to scrounge up, and I've got a couple of questions, which are probably obvious, but I just want to be sure...

Y1 (2.4576 MHz crystal), you've got Mouser part 449-LFXTAL003044BULK listed. I've got a 774-MP024S-E. The only real difference seems to be that mine has a 30 ppm tolerance, where yours is 20 ppm, and mine has a broader temperature range. These are interchangeable, right? Plus, I can take mine outside in the winter. ;)

C10 (100 nF cap), you've listed 581-SR205E104M and I have some 810-FA18X8R1E10400. The noteworthy difference here is yours are 50V and mine 25V. (Although again, I can apparently go outside in the winter!) For this project, I think a 25V is probably fine here. Can you confirm?

RP9, RP10, R00 (10k SIL), you have listed 4609X-AP1-103LF and I've got some 652-4609X-1LF-10K. These I am virtually certain are fine. :D

C46, C47, C48 (50 pF cap), the Mouser part you've updated to here is for a 47 pF, but column B specifies these as 50 pF. Is either one okay here? I have some 50s already.

Really starting to get excited about this project! :P
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exxos
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Re: H4 schematic

Post by exxos »

You don't "have" to use the parts I list. There are so many variations of tolerances and manufacturers and prices, that there could be 100 different versions of the same part. The ones listed between Rapid and Farnell are not always the exact part as listed in mouser anyway. I just generally went with one of the cheapest parts listed in mouser. Voltages on parts don't matter as long as they are higher than 5V. Generally 10V - 50V is the normal for a lot of stuff.

I know I listed 50pF and the part is 47pF. I keep meaning to change at in the file :roll: They are only really filter caps for the RGB outputs. It will actually work without them, but you may end up with some slight interference in the video. A few pF higher or lower is basically down to tolerance anyway, so it does not have to be exact.
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derkom
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Re: H4 schematic

Post by derkom »

Yeah I figured my bits were okay. Thanks for confirming. :)
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DoG
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Re: H4 schematic

Post by DoG »

Not much mention about the GAL for 1.44 floppy access. Is it a 20V8 I guess? I think I got some Lattice 20V8B 10ns laying around. Or is this a later project? Where is the jed file if it's already done? I think I might have missed it if you guys wrote about it in the past somewhere in that case.
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Re: H4 schematic

Post by exxos »

DoG wrote: Sat Nov 02, 2019 12:11 pm Not much mention about the GAL for 1.44 floppy access. Is it a 20V8 I guess? I think I got some Lattice 20V8B 10ns laying around. Or is this a later project? Where is the jed file if it's already done? I think I might have missed it if you guys wrote about it in the past somewhere in that case.
22V10, I can't do the GAL firmware until I have a made up board to do the firmware for it. So will take a while before that gets done.
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Re: H4 schematic

Post by exxos »

V3a BOM uploaded. Icky found wrong Rapid codes for R14,R36,R37.. In fact I can't find 75R in Rapid, so swapped the code for Farnell.
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JezC
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Re: H4 schematic

Post by JezC »

@exxos - I'm trying to go through the BoM whenever I have chance & have a list of chips & connectors with no price against them (some of which are the alternative package styles etc.)

A few of questions so far if I may:-

1- is the 68901 in PLCC likely to be tested soon or is it waiting on exxos getting his assembled board? so far it's down as not tested from what I can see...

2- the ST DAC is down as zero price...but I though I'd seen somewhere that they were being shipped out with the bare boards? So I don't know if it's fitted & a freebie (as for people buying the original bare boards - and I've ordered a bare board as well as the assembled one) or we have to order it from the store...

3- How have people socketed the DIL 68901 so far - can't see any source identified on the BoM for this (and BoM shows "NO SOURCE YET")? I'm not keen to solder it into the (assembled) H4 & don't really just want to use SIL strips except as a last resort...

Any info will be most gratefully received.
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Re: H4 schematic

Post by exxos »

JezC wrote: Wed Jan 15, 2020 5:33 pm 1- is the 68901 in PLCC likely to be tested soon or is it waiting on exxos getting his assembled board? so far it's down as not tested from what I can see...
The socket was only there for my use to test PLCC chips, so will have to wait until I get my board and have time. Doesn't really serve a purpose for anyone else.
JezC wrote: Wed Jan 15, 2020 5:33 pm 2- the ST DAC is down as zero price...but I though I'd seen somewhere that they were being shipped out with the bare boards? So I don't know if it's fitted & a freebie (as for people buying the original bare boards - and I've ordered a bare board as well as the assembled one) or we have to order it from the store...
All pre-orders have the DAC for free.
JezC wrote: Wed Jan 15, 2020 5:33 pm 3- How have people socketed the DIL 68901 so far - can't see any source identified on the BoM for this (and BoM shows "NO SOURCE YET")? I'm not keen to solder it into the (assembled) H4 & don't really just want to use SIL strips except as a last resort...
I since have a stock of the sockets in my store.
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JezC
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Re: H4 schematic

Post by JezC »

exxos wrote: Wed Jan 15, 2020 6:14 pm The socket was only there for my use to test PLCC chips, so will have to wait until I get my board and have time. Doesn't really serve a purpose for anyone else.
Ah, OK - best to go for the DIL package for that then :D
exxos wrote: Wed Jan 15, 2020 6:14 pm All pre-orders have the DAC for free
:yay2: :dualthumbup: :cheer: :thanksyellow:
exxos wrote: Wed Jan 15, 2020 6:14 pm I since have a stock of the sockets in my store
:cheers: :thumbup:

@exxos thanks for the prompt reply with that, I'll put together an order for the bits I know I need to get the first board finished & once that is running decide what I'm going to do with my blank board...

I'm guessing you are still in the dark re when they pre-assembled boards will be returned to you?
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