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Reverse Engineering the Macintosh SE PCB & Custom Chips for 1:1 reproduction
Posted by: Torbar on 2020-10-30 13:33:21 If making a custom PCB, it would be interesting to make a SWIM that works with standard IBM floppy drives instead. I like the idea of not being stuck with using the Apple drives, but the problem you'd run into with the IBM floppy drives, is it won't be able to handle 400k/800k disks, since there's a difference between how the drives read the disks/tracks. Which is why, to write a 800k/400k disk, you need a Mac with a built in floppy drive. Someone that knows more can probably explain in better detail why exactly that is?(Or if I'm wrong, tell me that too)
Posted by: quorten on 2020-10-30 20:35:08 Yeah, actually @Torbar, have you seen the FluxEngine? This basically is a board that uses IBM drives and a custom floppy disk controller to be able to read/write other formats like Macintosh 400k and 800k, via flux image streaming to a powerful computer... point in hand, it definitely should be possible.
Posted by: Torbar on 2020-10-31 08:21:04 Yeah, actually @Torbar, have you seen the FluxEngine? This basically is a board that uses IBM drives and a custom floppy disk controller to be able to read/write other formats like Macintosh 400k and 800k, via flux image streaming to a powerful computer... point in hand, it definitely should be possible. I have not heard of it, but just looked into it a bit. That's really cool!
Posted by: Kai Robinson on 2020-11-04 13:34:29 Well, apologies for the delay, been 'busy' with work lately and had 0 free energy left at the end of the day! However, thanks to Rob Taylor, the man responsible for getting me into the reverse engineering in the first place, I now have a new toy to play with! Finally a proper PAL dumper! Will get a ZIF socket but i have everything else I need - anyone else want one? 🙂
Posted by: Kai Robinson on 2020-11-04 13:34:58 @Torbar that parcel is finally on track to arrive, too - bloody customs wanted £15 to release it!! 😱
Posted by: Torbar on 2020-11-04 14:57:50 @Torbar that parcel is finally on track to arrive, too - bloody customs wanted £15 to release it!! 😱 :O I thought it was supposed to be only for packages over like £125 had a customs charge, but apparently not. that stinks!
Posted by: Kai Robinson on 2020-11-04 15:00:08 I think i can claim it back....i think :/
Posted by: Torbar on 2020-11-05 08:43:51 Not to turn this thread into an international shipping practices thread :lol: , but the first shipment wasn't held for customs payment or anything, right? only this most recent one?
Posted by: max1zzz on 2020-11-05 09:24:23 :O I thought it was supposed to be only for packages over like £125 had a customs charge, but apparently not. that stinks! "Gifts" up to a value of £35 or "Commercial Shipments" up to a value of £19 attract no import charges (That's including the cost of postage, and due to the cost of shipping these days almost no shipments will fall under these limits) anything over this will attract import VAT (20% + a £8 - £12 handling charge). There is a point where shipments may also attract duty or other import charges but I'm not 100% sure at what value this is Sometimes packages will slip through without getting a charge applied to them, but this is unfortunately quite rare Yeah, shipping into the UK sucks 🙁
Posted by: Torbar on 2020-11-05 09:35:56 "Gifts" up to a value of £35 or "Commercial Shipments" up to a value of £19 attract no import charges (That's including the cost of postage, and due to the cost of shipping these days almost no shipments will fall under these limits) anything over this will attract import VAT (20% + a £8 - £12 handling charge). There is a point where shipments may also attract duty or other import charges but I'm not 100% sure at what value this is Sometimes packages will slip through without getting a charge applied to them, but this is unfortunately quite rare Yeah, shipping into the UK sucks 🙁 Ah, thanks for clearing that up. That sucks. Not sure what I put down as the value of the first shipment, and if I put it as a gift or a commercial shipment, but I'm sure the value+postage was over 35GBP (Postage alone was 20GBP), so that one must have slipped by. first one I did the customs form by hand, 2nd one I did online. Maybe the first one they couldn't read my handwriting :lol:
Posted by: cheesestraws on 2020-11-05 13:46:21 @Kai Robinson sorry to drag this back to original topic 😉 could you post the latest version of the BOM? Perhaps I'm missing something but the only version I could see here, you said you'd made some changes to after it was posted, I think...
Posted by: Kai Robinson on 2020-11-06 11:28:20 Yes mate, let me dig it out 😀
Posted by: cheesestraws on 2020-11-06 12:15:13 Cheers! I've finally managed to feel human enough to concentrate on it 😀
Posted by: Kai Robinson on 2020-11-07 06:37:05 * Partlist from file: MacintoshSE.lay6" / 07/11/2020 00:32:29 * * Name Value * C1 100nF C2 100nF C3 100nF C4 33uF 16v C5 33 pF C6 100nF C7 100nF C8 100nF C9 100nF C10 100nF C11 33uF 16v C12 100nF C13 33uF 16v C15 100nF C16 33uF 16v C17 100nF C18 33pF C19 10pF C20 100nF C21 100nF C22 100nF C23 100nF C24 100nF C25 100nF C26 33uF 16v C27 100nF C28 100nF C29 100nF C30 100nF C31 100nF C32 33uF 16v C33 100nF C34 33uF 16v C35 100nF C36 1uF 16v C37 33uF 16v C38 33uF 16v C39 100nF C40 68pF C41 100nF C42 100nF C43 100nF C44 100nF C45 100nF C46 100nF C47 100nF C48 100nF C49 100nF C50 100nF C51 100nF C52 100nF C53 100nF C54 100nF C55 100nF C56 100nF C57 100nF C58 100nF C59 100nF C60 100nF C61 100nF C62 33uF 16v C63 100nF C64 100nF C65 100nF C66 100nF C67 100nF CR1 1N4150 CR2 1N4150 CR3 1N4150 J1 EAR Kobiconn 161-3520-EX J2 SERIAL TE 5749268-1 J3 SERIAL TE 5749268-1 J4 EXT SCSI Amphenol L77SDB25S1ACH4R J5 INT SCSI Molex 87831-5019 J6 EXT FLOPPY J7 UPPER DRIVE Molex 87831-5920 J8 LOWER DRIVE Molex 87831-5920 J9 ADB TE 5749181-1 J10 ADB TE 5749181-1 J11 Speaker J12 MAIN Molex 39-28-1143 J13 PDS TE 5535032-4 J14 SIMM PE Connectors HWS9229 J15 SIMM PE Connectors HWS9229 J16 1x3 HEADER L1 33uH L2 33uH L3 33uH L4 Ferrite Bead Q1 2N3904 R1 10k R2 10 R3 47 R4 47 R5 560k R6 10 R7 10 R8 1.2k R9 47 R10 47 R11 1k R12 150 R13 1k R14 470 R15 1k R16 3.3k R17 10k R18 1k R19 10 R20 75 R21 3.3k R22 47 R23 47 R24 47 R25 560 R26 3.3k R27 3.3k R28 47 R29 47 R30 47 R31 10k R32A 47 R33A 47 R34 10k R35 150 R36 150 R37 39 R38 39 R39A 47 R40A 47 R41 3.3k R42 39 R43 3.3k R44 3.3k R45 3.3k R46 3.3k R47 3.3k R48 3.3k RP1 39 Bourns 4610X-102-390LF RP2 39 Bourns 4610X-102-390LF U1C SND U2B FILTER Bourns 4120R-601-250/201 U2C 26LS30 U2E 74ACT257 U2F 74ACT257 U3C 26LS32 U4B FILTER Bourns 4120R-601-250/201 U4C 26LS32 U4D MC3488A U4E BBU U5D 85C30 SCC U6B 58C30 SCSI U6D ROM HIGH U7D ROM LOW U7E MC68000 U8B FILTER U8D SWIM U9D GLU U10C ADB U10D 16 Mhz Clock U11A ADB FILTER HALO LD11-0246FLF (24uH Common Mode 1:1:1:1 Choke) U11B FILTER Bourns 4120R-601-250/201 U11C RTC U11D Rockwell 338-6523 TPI U11F 74FCT245 U12F 74FCT245 Y1 32.768 KHz
Posted by: cheesestraws on 2020-11-07 09:46:13 Thanks!
Posted by: Kai Robinson on 2020-11-07 09:57:17 BTW - a reminder that U11D is just a standard 6522 VIA, the rockwell part number is misleading.
Posted by: Kai Robinson on 2020-11-07 14:04:19 Well it's a success, reads consistently as a 27C020 - no matter the manufacturer - although the AM27C020 seems to work best. So - here's the final code revision for the GLU logic - anyone able to verify this against the GLU's own description in Apple's own hardware manual? Name glu ; PartNo 00 ; Date 07/11/2020 ; Revision 01 ; Designer Kai Robinson ; Company Atmel ; Assembly None ; Location ; Device virtual ; /* Dedicated input pins / pin 1 = CLK; / Input / pin 2 = PB6; / Input / pin 3 = IRQ; / Input / pin 4 = WRDATA; / Input / pin 5 = ENABLE1; / Input / pin 6 = PA4; / Input / pin 7 = 16MCLK; / Input / pin 8 = PA3; / Input / pin 9 = RTXCB; / Input / pin 11 = OE; / Input / / Programmable output pins / pin 12 = RTXCA; / Combinatorial output / pin 13 = OUTA; / Fixed high output / pin 14 = BBUIRQ; / Combinatorial output w/ output enable / pin 15 = ENABLEL; / Combinatorial output / pin 16 = ENABLEU; / Combinatorial output / pin 17 = FLOPPYWR; / Combinatorial output / pin 18 = nc; / Fixed high output / pin 19 = FCLK; / Combinatorial output w/ output enable / / Output equations / !FCLK = 16MCLK & !OE; nc = 'b'1; !FLOPPYWR = WRDATA; !ENABLEU = !ENABLE1 & !PA4; !ENABLEL = !ENABLE1 & PA4; !BBUIRQ = !PB6 & IRQ; OUTA = 'b'1; !RTXCA = !PA3 & !RTXCB & !OUTA # PA3 & !RTXCB & !OUTA # !PA3 & RTXCB & !OUTA # PA3 & !RTXCB & OUTA; / End */
Posted by: quorten on 2020-11-09 14:34:35 `OUTA` and `RTXCA` look suspect, `RTXCA` will always be one with that logic so apparently you cannot enable synchronous modem use? Not like you could ever do it in earlier Macintosh computers... I'm guessing the hardware manual's passing mention of this is because the feature was cancelled late in the product development. Otherwise, I'd say everything else looks good when also consulting the VIA register layouts in the hardware manual. Also, I've looked a little into implementing a BBU clone and started coding up some Verilog. I'd say implementing the embedded asynchronous DRAM controller feels like it's the most complicated part, that being said most of the rest of the BBU functions are simple combinatorial logic or counting loops for things like scanning the video buffer, sound buffer, etc. Mentioning the BBU, one thing I don't quite understand is how the Macintosh SE controls the boot-time memory overlay. Earlier Macintoshes used a VIA register bit to control the switch, but there is no such bit reserved in the Macintosh SE's VIAs. Also, perusing emulator source code seems to have reached the limit of its helpfulness at this point, looks like a lot of how Mini vMac, MAME (formerly MESS), and PCE implement the finer details of Macintosh SE BBU emulation is through borrowing an emulation of a Macintosh Plus and patching ROM hacks in place for SCSI support.
Posted by: 360alaska on 2020-11-09 14:44:25 Look, I found N.O.S Maxell, looks like it might work my IIFX or a newly created SE logic board: https://www.diytrade.com/china/pd/15028592/Maxell_3_6V_1_2_AA_Lithium_thionyl_chloride_battery_ER3.html
Posted by: quorten on 2020-11-09 18:56:55 Well if those Maxells aren't already exploded from sitting in inventory they must have something good about them! I have to admit, it's tempting to see leaded solder-in batteries being sold... yeah you could just solder in another battery for a more authentic looking board, but it's totally punitive to not use a battery holder or connector of some sort.
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