Sporniket's log on hardware stuff

Blogs & guides and tales of woo by forum members.
sporniket
Posts: 256
Joined: Sat Sep 26, 2020 9:12 pm
Location: France
YouTube: UCiQFiAzVUqT9cMTPAh7ZTAw
Contact:

Re: Sporniket's log on hardware stuff

Post by sporniket » Sat May 08, 2021 6:00 pm

This week I could capture the schematics around the MFP. I planned to put the serial port too, but this one is not just wiring to IO ports, there are specialized ICs and voltage regulation curcuitery. I also had to fix the previous subsheet, with a forgotten capacitor and the parallel port and wiring incorrectly labelled with "serial" everywhere ! :oops:

As usual, the git repository is up to date.

subsheet_202-U202 — PSG and Parallel IO.pdf
(54.46 KiB) Downloaded 45 times
subsheet_203-U203 — MFP 68901.pdf
(50.64 KiB) Downloaded 43 times

sporniket
Posts: 256
Joined: Sat Sep 26, 2020 9:12 pm
Location: France
YouTube: UCiQFiAzVUqT9cMTPAh7ZTAw
Contact:

Re: Sporniket's log on hardware stuff

Post by sporniket » Thu May 13, 2021 6:35 am

The RS-232 port and alternate voltage generation. The "-12V" is just a hunch given that it is for the RS-232 driver. In other words, "I have no idea what I'm doing".

subsheet_204-J204 — RS-232 IO.pdf
(47.72 KiB) Downloaded 44 times
subsheet_205-U204 U205 — G12V -12V -5V.pdf
(39.58 KiB) Downloaded 44 times

Anyway, the sheet #2 is done, next sheet is the DMA circuitry (DMA, WD1772 and ports).

As usual, the github repository is up to date.

sporniket
Posts: 256
Joined: Sat Sep 26, 2020 9:12 pm
Location: France
YouTube: UCiQFiAzVUqT9cMTPAh7ZTAw
Contact:

Re: Sporniket's log on hardware stuff

Post by sporniket » Sun May 16, 2021 9:25 pm

Here is the converted schematics for the DMA IC. The original schematics is done with the DIP-40 version of chip, and my STE has the PLCC44 version. Thus, I looked at other schematics (the Mega STE and the STBooks) to also get the pinout of the plcc version. The schematics of the STBooks seems more complete to me, as the pin 30 is annotated as "TESTIN" and wired to ground, instead of being omitted in the schematics of the Mega STE.

Another thing, on my motherboard, I fail to find a second bypass capacitor, as the plcc version has 2 Vcc pins.

subsheet_300-U300 — DMA.pdf
(54.53 KiB) Downloaded 40 times

The git repository is up to date.

sporniket
Posts: 256
Joined: Sat Sep 26, 2020 9:12 pm
Location: France
YouTube: UCiQFiAzVUqT9cMTPAh7ZTAw
Contact:

Re: Sporniket's log on hardware stuff

Post by sporniket » Fri May 21, 2021 7:55 pm

Next subsheet, the ACSI Port, and the associated buffer/line drivers ICs.

subsheet_301-J301 — ACSI Port.pdf
(52.35 KiB) Downloaded 36 times

The git repository is up to date.

Also, this week I received the 4Mb SIMMs for STE made by @exxos to upgrade from 512Kb RAM.

2021-05-21--00.jpg
2021-05-21--00.jpg (148.2 KiB) Viewed 3009 times

I had to push harder than expected to fully engage the SIMMs in the connector. Simply place and push is not enough.

2021-05-21--01.jpg
2021-05-21--01.jpg (53.68 KiB) Viewed 3009 times

Anyway, it was a success

2021-05-21--03.jpg
2021-05-21--03.jpg (4.55 KiB) Viewed 3009 times

Now that my STE has more than 512Kb RAM, I can finally run Gembench. (And yaart tested successfully too)

2021-05-21--02.jpg
2021-05-21--02.jpg (82.48 KiB) Viewed 3009 times

sporniket
Posts: 256
Joined: Sat Sep 26, 2020 9:12 pm
Location: France
YouTube: UCiQFiAzVUqT9cMTPAh7ZTAw
Contact:

Re: Sporniket's log on hardware stuff

Post by sporniket » Mon May 24, 2021 8:38 am

The FDD controller and ports. The subsheet is quite full. I also took time to finally put a licence note on the page layout descriptor.

subsheet_302.sch
(26.8 KiB) Downloaded 32 times

The git repository is up to date.

sporniket
Posts: 256
Joined: Sat Sep 26, 2020 9:12 pm
Location: France
YouTube: UCiQFiAzVUqT9cMTPAh7ZTAw
Contact:

Re: Sporniket's log on hardware stuff

Post by sporniket » Mon May 24, 2021 2:56 pm

The generation of SCLK and CLK2 was quick to do, and that's the end of the sheet #3. Next sheet deals with the GSTMCU, the shifter, and the video circuitry, it won't be so quick to capture...

subsheet_303.sch
(3.82 KiB) Downloaded 26 times

The git repository is up to date.

sporniket
Posts: 256
Joined: Sat Sep 26, 2020 9:12 pm
Location: France
YouTube: UCiQFiAzVUqT9cMTPAh7ZTAw
Contact:

Re: Sporniket's log on hardware stuff

Post by sporniket » Thu May 27, 2021 8:22 am

I have just finished the GSTMCU. It fits the A4 page !!

subsheet_400.sch
(26.92 KiB) Downloaded 26 times

The github repository is up to date.

sporniket
Posts: 256
Joined: Sat Sep 26, 2020 9:12 pm
Location: France
YouTube: UCiQFiAzVUqT9cMTPAh7ZTAw
Contact:

Re: Sporniket's log on hardware stuff

Post by sporniket » Sat May 29, 2021 10:57 pm

The shifter

subsheet_401.sch
(18.4 KiB) Downloaded 29 times

The git repo is up to date.

sporniket
Posts: 256
Joined: Sat Sep 26, 2020 9:12 pm
Location: France
YouTube: UCiQFiAzVUqT9cMTPAh7ZTAw
Contact:

Re: Sporniket's log on hardware stuff

Post by sporniket » Mon May 31, 2021 3:04 pm

Hum, how embarassing. It seems that recently, I have attached the kicad subsheets instead of the pdf tracing... :oops:

subsheet_302-U301 — WD1772 and port.pdf
(111.08 KiB) Downloaded 30 times
subsheet_303-U303 — SCLK & CLK2 clocks.pdf
(50.36 KiB) Downloaded 22 times
subsheet_400-U400 — GSTMCU.pdf
(117.56 KiB) Downloaded 28 times
subsheet_401-U401 — GST Shifter.pdf
(84.22 KiB) Downloaded 24 times

sporniket
Posts: 256
Joined: Sat Sep 26, 2020 9:12 pm
Location: France
YouTube: UCiQFiAzVUqT9cMTPAh7ZTAw
Contact:

Re: Sporniket's log on hardware stuff

Post by sporniket » Tue Jun 01, 2021 9:15 pm

Today I completed the Video Port. The github repository is up to date.

subsheet_402-J400 — Video Port.pdf
(92.35 KiB) Downloaded 42 times

Post Reply

Return to “MEMBER BLOGS”