Products > Test Equipment
Some old school instruments showing how it's done (HP 3325A and Fluke 8506a)
m k:
--- Quote from: joeqsmith on February 23, 2021, 05:16:31 pm --- And with the power of Google,
--- End quote ---
Like when I couldn't remember witch one the LPT1 address is and tried google.
It wasn't there, I had to change to I/O map and first one didn't even have LPT2.
Maybe Altavista had better SNR.
SilverSolder:
--- Quote from: m k on February 23, 2021, 07:41:15 pm ---
--- Quote from: joeqsmith on February 23, 2021, 05:16:31 pm --- And with the power of Google,
--- End quote ---
Like when I couldn't remember witch one the LPT1 address is and tried google.
It wasn't there, I had to change to I/O map and first one didn't even have LPT2.
Maybe Altavista had better SNR.
--- End quote ---
If you put Google in "Verbatim" mode, it becomes almost usable.
joeqsmith:
Google "ISA" "printer port" "address"
Second hit was
https://en.wikipedia.org/wiki/Parallel_port
Which states:
Most PC-compatible systems in the 1980s and 1990s had one to three ports, with communication interfaces defined like this:
Logical parallel port 1: I/O port 0x3BC, IRQ 7 (usually in monochrome graphics adapters)
Logical parallel port 2: I/O port 0x378, IRQ 7 (dedicated IO cards or using a controller built into the mainboard)
Logical parallel port 3: I/O port 0x278, IRQ 5 (dedicated IO cards or using a controller built into the mainboard)
If no printer port is present at 0x3BC, the second port in the row (0x378) becomes logical parallel port 1 and 0x278 becomes logical parallel port 2 for the BIOS.
Of course, having used the PC since the start,
debug - start the debugger
d 40:0 - display the addresses of the printer ports in order
That stuff seems embedded in the memory banks. :-DD
joeqsmith:
--- Quote from: SilverSolder on February 23, 2021, 07:31:08 pm ---
Yeah, I've also got a "mule" meter for hacking/testing/repairing modules. I like having at least two of each boat anchor because they can be hard to troubleshoot if you don't have a working one to compare with!
>My guess is that thing is loaded with a lot of 1's and a few 0's sprinkled in the mix.
A remarkably astute guess, you might just be right! :D
--- End quote ---
Well, I'm at a total loss about U18. I removed the device without damaging the PCB and installed the same type socket so it looks somewhat the part. My board uses a DM74S287N. The programmer supports it no problem but when I read it, the results are very unexpected. I did reinstall the part and powered up the meter. No problems at all. I wonder if this is a problem with my programmer or if this is really the contents as it appears all the bits were set (this part is cleared to all zeros). If anyone has a programmer that supports it, I would be very interested in knowing if you have the same results.
When is the last time you heard of Titanium Tungsten Fuses?
Also, I had mentioned that the cheapo programmer was having a problem with some Lattice GAL22V10Bs. I tested the parts I thought I may have damaged in the real programmer and no problems. They erase and program just fine. So I put them back into the TL866II plus and the problem again repeats, bad pins. But I noticed that it works correctly the first time every time. Then I noticed that if I repeat the same process, Read for example, too fast, the pin error happens. Almost like I am dragging down a supply and it takes time to recharge. :-DD
SilverSolder:
The file you attached isn't cleared to all zeroes? Here's what I see in the file, it looks interesting - note the '07' snuck in line 1 and line 9.
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