nice! my one part mouser didnt have that jameco did came today. the tiny trim pot 🤣! so small. just waiting on my v20 from china.
--/\-[ Stu : Bloody Cactus :: [ https://bloodycactus.com :: http://kråketær.com ]-/\--
Good luck. That was so damn much soldering...
sockets and decoupling caps, battery holder, ps2 connections...
--/\-[ Stu : Bloody Cactus :: [ https://bloodycactus.com :: http://kråketær.com ]-/\--
Apparantly I ordered the wrong RTC:
Do you think the DS12C887+ will be compatible with DS12887A+ that the BOM suggests?
www.mouser.com/ProductDetail/Maxim-Inte ... J8VExDE%3d
vs.
http://www.mouser.com/ProductDetail/Maxim-Int … P35CksHxtng8%3D
The only difference I can see seems to be that the suggested part has "binary" date/time, but one of the Jameco suggested pieces does as well. Does the "C" stand for CMOS as it did for some of the other parts?
Also, I JUST realized I have no way to program the BIOS on this thing...
wrote:Also, I JUST realized I have no way to program the BIOS on this thing...
https://www.flashrom.org/Flashrom
Use a NIC with an EEPROM socket 😀
Check out my blog and YouTube channel for thoughts, articles, system profiles, and tips.
Actually my XT-IDE adapter uses a 32kb SST flash, I wonder if I can use that to flash the chip.
Well yeah, it looks like the part number for the xi8088 is the same as the part I ordered for my lo-tech xt-ide card? that's odd.
*edit*
Yeah even HMM'er, I thought that the xt-ide part was 32kb, but it's 128kb * 8, so it's exactly the same part. that explains why I had such a hard time with a second rom that shouldn't have overlapped.
SO yeah, I should 100% be able to use my lotech xt-ide adapter to flash that chip, yay me.
*/edit*
I have a genius G840, it can do the SST 39SF010A from the BOM. If you get desperate, I can burn it for you. I can burn the SST ones, not sure about the Greenliant ones (probably, it should be the exact same pinout).
--/\-[ Stu : Bloody Cactus :: [ https://bloodycactus.com :: http://kråketær.com ]-/\--
looks like the DS12887A and the DS12C887A are the same. They share the datasheet. Looks like the C version has a century register/byte in the midst of its ram page that the non-C versions dont have.
if the board does not use the ram on the rtc (I dont know), it will be ok.
--/\-[ Stu : Bloody Cactus :: [ https://bloodycactus.com :: http://kråketær.com ]-/\--
Looks like the clock RAM is the cmos setup ram.
*edit*
Aha.
;-------------------------------------------------------------------------
; locations in RTC and NVRAM
cmos_seconds equ 00h ; seconds location in RTC
cmos_alarm_secs equ 01h ; alarm seconds location in RTC
<etc>
cmos_equip equ 14h ; equipment byte
cmos_sum_hi equ 2Eh ; checksum of bytes 10h - 20h - high byte
cmos_sum_lo equ 2Fh ; checksum of bytes 10h - 20h - low byte
cmos_century equ 32h ; centry location in RTC (DS12C887 only)
Looks like the rtc.inc file already accounts for the century location in the DS12C887, and also only uses bytes 10h - 20h anyway so there'd be no overlap.
yay.
DAMMIT.
Can anyone see what I've done wrong here? It's not exactly subtle.
🤣, SOIC 😀
--/\-[ Stu : Bloody Cactus :: [ https://bloodycactus.com :: http://kråketær.com ]-/\--
🙁
Frys has a 74S74 in stock. I was thinking that should just be a faster version of ALS/LS, but it describes it in the datasheet as an "edge-triggered" flip-flop?
Think that'll work?
So close, yet so far.
FWIW all 74xx74 are edge-triggered. Go for it. http://web.mit.edu/6.111/www/s2007/datasheets/74LS74.pdf https://www.fairchildsemi.com/datasheets/DM/DM74ALS74A.pdf
I/O, I/O,
It's off to disk I go,
With a bit and a byte
And a read and a write,
I/O, I/O
Ah thanks. The descriptions on mouser/digikey were subtly different, so i wasn't 100% positive. I'll pick up a few today at lunch and hopefully be playing Conquest of Camelot on this just after dinner.
Frys only had one 74S74, the others are 74LS74...
Still had to order some off the internet. I'll try the 74LS74 and at least see if I can get a boot. May have to disable turbo or it may not work at all, but I'll try...
Seriously, at 8MHz (and even more so at 4.77) LS vs. S vs. F vs. AHCT vs. ACT vs. HCT vs. ALS is moot. Any will work.
Worry about propagation delay per gate once you get into the 30-40MHz range only.
I/O, I/O,
It's off to disk I go,
With a bit and a byte
And a read and a write,
I/O, I/O
This is just damned idiotic.
I can't flash with the xt-ide flash.exe because it won't flash anything larger than 64k, and the xiflash isn't usable because it refuses any address < E000.
The second half of bios128k.bin is blank. I have cut the first half that has the actual code, and am attaching it here. Try it.
Also let me see if I can compile a version of xiflash without the E000 limit.
I/O, I/O,
It's off to disk I go,
With a bit and a byte
And a read and a write,
I/O, I/O
R.I.P. my board, maybe?
I managed to get the 32kb section of actual code flashed but it wouldn't boot. I placed the jumper to enable the on-board speaker (jumpers 1+ 2), powered it on, and immediately smelled smoke.
Turned everything off and re-checked. Apparantly I jumpered 3 + 4, not 1 + 2, so I shorted +5v to ground. I have no idea if this may have damaged anything.
Try this xiflash, it should have the E000 limit removed.
I/O, I/O,
It's off to disk I go,
With a bit and a byte
And a read and a write,
I/O, I/O
