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Book 8088 discovery and modification thread
- Thread starter Retroplayer
- Start date
n0p
Experienced Member
Yep, that might be the case. But running START.EXE in DOSBox (EGA) and setting cycles close to XT (300) results in same sluggish cursor behaviour.
--
I need help
As i got my V2 fixed, i decided to clean up my V1. Cleaned chips and inserted CP82C84A in wrong direction (don't judge). It broke for sure. I've took same one from V2, just to test - it worked. That was yesterday. I considered that as minor problem as many of those 8088 era chips are still available here new (was produced locally as replicas of 8284). And really cheap (that's 0,25USD for one) , so i ordered five of them, hoping even if some bad, some might work. Today i got them and started testing - for my suprise none worked (system doesn't init)
Any ideas on the reason they don't work in Book? I pretty sure that voltage and pinout are identical. As for functionality - it meant to be a full replica of 8284 chip, and i had that exact one on my old XT clone.
Photos: working chip with Harris mark, chip i've burnt (Intersil), one of five chips i tested (Електронмаш)
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Electronizer
New Member
- Joined
- May 31, 2019
- Messages
- 6
Yep, that might be the case. But running START.EXE in DOSBox (EGA) and setting cycles close to XT (300) results in same sluggish cursor behaviour.
--
I need help
As i got my V2 fixed, i decided to clean up my V1. Cleaned chips and inserted CP82C84A in wrong direction (don't judge). It broke for sure. I've took same one from V2, just to test - it worked. That was yesterday. I considered that as minor problem as many of those 8088 era chips are still available here new (was produced locally as replicas of 8284). And really cheap (that's 0,25USD for one) , so i ordered five of them, hoping even if some bad, some might work. Today i got them and started testing - for my suprise none worked (system doesn't init)
Any ideas on the reason they don't work in Book? I pretty sure that voltage and pinout are identical. As for functionality - it meant to be a full replica of 8284 chip, and i had that exact one on my old XT clone.
Photos: working chip with Harris mark, chip i've burnt (Intersil), one of five chips i tested (Електронмаш)
The 82C84 is a CMOS part. The datasheet shows a 40mA current draw. In contrast, 8284 nMOS chips draw from 140-160mA. If the KR1810GF84 chip is also nMOS, it might be drawing too much current. Have you tried measuring Vcc on the KR1810GF84 and comparing it with Vcc on the good Harris chip? If there's high current draw and the board can't support it, it might be causing a voltage drop.
Krangerich
New Member
- Joined
- Dec 19, 2023
- Messages
- 9
The first ones are CMOS ones and both usually work with small capacitors on X1 and X2. The КР1810ГФ84 is a NMOS version and these usually work with 510 Ohm resistors insteadYep, that might be the case. But running START.EXE in DOSBox (EGA) and setting cycles close to XT (300) results in same sluggish cursor behaviour.
--
I need help
As i got my V2 fixed, i decided to clean up my V1. Cleaned chips and inserted CP82C84A in wrong direction (don't judge). It broke for sure. I've took same one from V2, just to test - it worked. That was yesterday. I considered that as minor problem as many of those 8088 era chips are still available here new (was produced locally as replicas of 8284). And really cheap (that's 0,25USD for one) , so i ordered five of them, hoping even if some bad, some might work. Today i got them and started testing - for my suprise none worked (system doesn't init)
Any ideas on the reason they don't work in Book? I pretty sure that voltage and pinout are identical. As for functionality - it meant to be a full replica of 8284 chip, and i had that exact one on my old XT clone.
Photos: working chip with Harris mark, chip i've burnt (Intersil), one of five chips i tested (Електронмаш)
n0p
Experienced Member
I'm happy to announce that my postponed Book8088 V1.5 (one and a half) project is now complete
My Book8088 V1 now has both fully functional external screen and keyboard connectors.
I received and soldered back keyboard microcontroller (received even two, so if anyone wants the firmware and has a working method to do it - i might try), as testing showed - Pico inputs should be pulled up to work with it (github sources updated).
Also increased a bit length of keyboard "cycle" to work better in Loderunner and Shamus, that tend to suffer from "stuck" key - not getting release properly.
This time i supplied 3.3V to microcontroller from Pico itself and everything worked fine.
USB-C hole is not that good as i had to move Waveshare Zero a bit from planned position.
Anyway:
My Book8088 V1 now has both fully functional external screen and keyboard connectors.
I received and soldered back keyboard microcontroller (received even two, so if anyone wants the firmware and has a working method to do it - i might try), as testing showed - Pico inputs should be pulled up to work with it (github sources updated).
Also increased a bit length of keyboard "cycle" to work better in Loderunner and Shamus, that tend to suffer from "stuck" key - not getting release properly.
This time i supplied 3.3V to microcontroller from Pico itself and everything worked fine.
USB-C hole is not that good as i had to move Waveshare Zero a bit from planned position.
Anyway:
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PerditionC
New Member
- Joined
- Feb 6, 2024
- Messages
- 1
Thank you for this! clmode m2+ did the trick to get VGA modes with visible output (instead of blank/black screen). I tested earlier and thought everything worked, but I have since flashed a few different BIOS images and hooked up a few extra ISA cards and couldn't recall if it ever worked, but after doing as you suggested, it seems to be working. My VGA is the Cirrus Logic CL-GD5422-75QC-A with only 256KB.
Hi all
Signed up so I could join this thread. I want to say a huge thank you first of all to everyone who has contributed their experiences here, and especially to @sergey and @n0p for your work on the BIOS.
I have a v2 Book 8088 with the ISA expansion board (so far untested). Took a while for my new flash chips to arrive, but now they're here I've replaced the shipped BIOS with the @n0p 1.0.6 version. That has very much given the machine a new lease of life, especially the USB Floppy functionality that's built in - I've built a whole new CF card by booking an MS-DOS install disk imaged to USB via Rufus. Windows looks good in EGA as others have confirmed, but VGA just produces a blank/black screen with the AVGA drivers I've seen linked elsewhere.
I haven't been able to confirm which firmware is on the display driver board yet, but have ordered some EEPROM's from China so once they get here I'll program one of them and replace the stock one and see if that makes any difference.
Regards external displays - I saw the RGB2HDMI mod detailed for the v1 Book - is that also possible for the v2 or not possible on the VGA version? I've not had time to go over the PCB in depth yet so if someone else already knows it'll save me going down a dead end route.
If I discover anything cool/interesting I'll post it here - otherwise my gratitude to everyone else for all the great work!
Signed up so I could join this thread. I want to say a huge thank you first of all to everyone who has contributed their experiences here, and especially to @sergey and @n0p for your work on the BIOS.
I have a v2 Book 8088 with the ISA expansion board (so far untested). Took a while for my new flash chips to arrive, but now they're here I've replaced the shipped BIOS with the @n0p 1.0.6 version. That has very much given the machine a new lease of life, especially the USB Floppy functionality that's built in - I've built a whole new CF card by booking an MS-DOS install disk imaged to USB via Rufus. Windows looks good in EGA as others have confirmed, but VGA just produces a blank/black screen with the AVGA drivers I've seen linked elsewhere.
I haven't been able to confirm which firmware is on the display driver board yet, but have ordered some EEPROM's from China so once they get here I'll program one of them and replace the stock one and see if that makes any difference.
Regards external displays - I saw the RGB2HDMI mod detailed for the v1 Book - is that also possible for the v2 or not possible on the VGA version? I've not had time to go over the PCB in depth yet so if someone else already knows it'll save me going down a dead end route.
If I discover anything cool/interesting I'll post it here - otherwise my gratitude to everyone else for all the great work!
n0p
Experienced Member
You're welcome!
For VGA issues you can ask seller for replacement LCD board - they would send it w/o any problems. Simplest way to check LCD fw - set mode 12h (via checkit or https://github.com/jinshin/Book8088/blob/main/MODE12H.COM). Blank screen - you have CGA firmware.
To some point, external screen mod for VGA would be easy, as it already has VGA connector, just in different form and doesn't require any convertors. But it won't look nice.
You'll need to make a connector, for board it's 12P 1.25mm https://www.aliexpress.com/item/1005006003135511.html and solder a VGA DE-15 to it.
Board connector pinout attached
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Is it possible to connect a floppy disk drive to the Book 8088's parallel port (LPT1)?
https://www.amazon.com/NEC-External-Floppy-875542-006-136-275492-032/dp/B08QV7FX38
https://www.amazon.com/NEC-External-Floppy-875542-006-136-275492-032/dp/B08QV7FX38
Yrouel
Member
Even if that's actually parallel and not just the standard floppy signaling brought out you would still need to make a cable.
If you have the ISA expansion board you can just use any common multi I/O board with floppy controller and a normal floppy drive or even a Gotek
I bought the above-mentioned drive and will test it. I will let you know if it works.
Do you think that the following BIOS mod will allow for a USB floppy drive to work with the Book 8088?
github.com
Do you think that the following BIOS mod will allow for a USB floppy drive to work with the Book 8088?
Home
BIOS for Book8088. Contribute to jinshin/8088_bios development by creating an account on GitHub.
github.com
n0p
Experienced Member
I bought the above-mentioned drive and will test it. I will let you know if it works.
Do you think that the following BIOS mod will allow for a USB floppy drive to work with the Book 8088?
Home
BIOS for Book8088. Contribute to jinshin/8088_bios development by creating an account on GitHub.
No, it won't work with USB floppy drive (unless it presents itself as mass storage device). It's oriented at using USB flash/thumb drives.
Thanks @n0p - I hadn't realised the internal connector was actually VGA on the pins. I've ordered the requisite parts to make up a VGA cable so will give it a go once the parts arrive. I can see it wouldn't be pretty as you say, but going to just test it out first and then think about appearance and if it's something I want to take further.
Your mode12h.com tool was invaluable and confirmed that I do indeed have the CGA firmware. I bought the book about 2 months ago so I wasn't sure if the seller would provide a positive response, but I have two keys on the keyboard that don't work well (you have to press them really hard to get them to work) so I wrote all this down nicely for the seller on Aliexpress and they've promised to send me a new keyboard and display driver board - can't argue with that! I'm not sure how long they'll take to arrive but looking forward to getting the Book to an improved state! Will update here when I have any news to report.
For reference. On the V1 and V2 (though I only have a V2, so you'll have to verify orientation if you have a V1).. if you want to force full time turbo mode (8 Mhz), you have the option of lifting a ping on the BK chip, blocking pin 61 on the CPLD, or what I finally wound up doing (after trying pin lift on the BK chip and not liking the precariousness of the pins)... it's a dual layer board, so you can cut the trace shown and it will force full time 8 Mhz. The trace comes off of pin 14, which is also shown in the picture (previously posted by n0p that I've reposted, and my picture below showing the cut). What I plan on doing is wiring a switch/jumper between both sides of the trace so i have a hardware turbo switch. On the V1, the BK chip is on the front near the sound card, on the V2 it was moved to the back near the video card just above/below the audio jack (depending on how you have the back of the board orientated).
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and.. here are more pics... one with it all as i wanted.. one with the video card back in place... and... one where the audio jack finally gave up and 'let go'.. (which is fine, i don't need a headphone jack anyway)... and that was AFTER it did it partly once and i refortified it...
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Yrouel
Member
To clarify, is this cut the only thing needed to force turbo? Does the led light up with this method?
No, no LED.. and actually.. I just tried something.. and apparently it's the opposite. (so it's n0p's fault.. lol and now i can't delete my post)
@n0p If I put my jumper on, i can switch between 4.77 and 8... but with the jumper off, it's ONLY 4.77... (according to syscheck).. so it appears we were slightly wrong..... gah. Did you test or was this all just from the schematic?
Signed up so I could join in on this thread.
I've had my Book 8088 v2 for about a week now. Not sure what I was expecting, but I think it pretty much met expectations.
Based on what's been posted on this thread, I have a few questions:
1) The updated LCD driver that fixes the VGA modes - How does one go about getting one? Just contact the seller via AliExpress? It looks like the main difference is what's flashed on a chip on that board, has anyone figured out how to re-flash one of the boards that shipped with the device?
2) I've tried a couple of the 8088 demos - 8088MPH and Area5150. Both of them are aimed at CGA graphics, but my v2 came with VGA and it looks like these demos bang on the CGA low-level stuff so I get a lot of garbage on the screen. Any known fixes for that? Or should I see if I can track down one of the CGA cards if I want to be able to watch those? (DZT seems to be the only seller on AE and he's sold out).
3) Is it worth it to try and update the BIOS? If it is, is there anyone in the greater Austin, TX area in here that has an EPROM programmer?
If you still need EEPROM programming, I just received a programmer this week. Still waiting on new EEPROMs to test it with. I commute between SE Austin and the Oakhill area pretty much daily. Take care!