Products > Test Equipment
Some old school instruments showing how it's done (HP 3325A and Fluke 8506a)
joeqsmith:
Good old DOSBox. Here's the current setup.
https://www.youtube.com/watch?v=CA-wbjTBMYk&feature=youtu.be
dietert1:
OK, appended the checksum calculation of the Fluke 8502A firmware 3.0.0.
Meanwhile i checked in that EPROM set the first three give a zero remainder as well, so the fourth EPROM is kind of add-on and there are two unused adjustment bytes, one for 0x0000 .. 0x2FFF and one for 0x3000 .. 0x3FFF.
Regards, Dieter
SilverSolder:
--- Quote from: joeqsmith on March 02, 2021, 12:45:00 pm ---[...] That meter is just so compact its going to take some more custom adapters to instrument it. :-DD
--- End quote ---
You could always run it without the I/O card at the back, to get some space "over" the controller board? It runs fine without any I/O card at all.
joeqsmith:
--- Quote from: dietert1 on March 02, 2021, 02:55:41 pm ---OK, appended the checksum calculation of the Fluke 8502A firmware 3.0.0.
Meanwhile i checked in that EPROM set the first three give a zero remainder as well, so the fourth EPROM is kind of add-on and there are two unused adjustment bytes, one for 0x0000 .. 0x2FFF and one for 0x3000 .. 0x3FFF.
Regards, Dieter
--- End quote ---
Thank you very much. It's very similar in the 8506A but there isn't an embedded port call. It's too bad the 8502A's controller is so different from the 8505/6. It looks like you have made a lot of progress sorting out the firmware. I don't understand enough about the hardware yet to make sense of it. It may not seem like much but all these little bread crumbs of yours have been a big help.
--- Quote from: SilverSolder on March 02, 2021, 03:31:52 pm ---You could always run it without the I/O card at the back, to get some space "over" the controller board? It runs fine without any I/O card at all.
--- End quote ---
The card in the back is the serial communications board. The plan is to modify the firmware to take advantage of the higher BAUD rate after modifying the clock generator circuit.
An extender board would be nice but I think I have an easier way to do it.
joeqsmith:
It appears that the serial communications is not done in the foreground. I knew the receive side of the board supported interrupts but it appears they use interrupts for the transmit as well. It seems interrupt 0x20 (RST4) is the one being used which is running from RAM.
Have you sorted out where the copy from PROM to RAM happens? Mapped out the different sections?
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