Need some help ... please
So I made a wire--wrap board, programmed a PAL as address decoder (nAS=L, A31=H, A24=L) that generates nDSACK0 signal and seems to be working. Used Chipmunk basic poke 0x0e0000000,0 and peek to test it and works fine, without the board the SW crashes as expected.
But...
I could not find any LocalTalk interface box in my country for months until this weekend, close to me and 'new in box' !
Original shipping label on the box was from 1994 to Bourns Holding BV.
Don't think I will get another five times this Lucky to build an original Apple network at home ...
I made a simulation of the PAL and it's clear it sends out an 768k clock onto one of the connectors pin.
Still not sure how all the signals on the connector are connected to the computer,
without the real HW on hand, the only way to find out is to try it out.
Got most of the HW for it.
But for...
Plan to used for : I have a couple of Tektronix bench devices and an HP Logic analyzer to play with. All from the same era as the Macintosh.
So I just got all the parts to start the prototype and by accident I found a tech article by Apple [Technote HW 07] on the internet saying you should...
Yes, there is very complex design that delays incoming data and possible detects the speed of it (this last is only an idea).
No the higher clock only goes to the Macintosh computer side, not the network.
It was because of this statement and drawing, it shows the Macintosh computer able to...
Hi,
I did a draft reverse engineering of the schematics based on the photo's and found some interesting things :
1. Of the differential transceiver SN75176 only the receive part is used, the transmitter is continues disabled (pin 3 to GND).
This means the data is coming directly out of...
I'm building a small PDS board for my LC with wire wrap for fast debugging a proof of concept.
Will be an GPIB controller with a simple u7210 chip, bare minimum address decoder (as done above).
1. Now I'm wondering if there is a difference in writing to the PDS I/O address space between the LC...
Hi Igjk1,
Do you still have this card or the manuals please ? I would like to build a GPIB card for the LC and this would be a nice starting place
Br,
Steve
Hi MindWalker,
I'm at the point to build my homebrew version of faster LocalTalk by using an external clock.
I'm currently blocked at how to select the external clock, I made as small program but seems some driver is changing it also in the background.
How did your machine feel like speed...
I was super happy today when I found an 256MB stick between some old stuff, but when I installed it, there was only 128MB detected.
But 128 + 64 + 32 = 204MB should be enough to do some programming ?
PS On my machine there is an free FDD power cable hanging lose and I have already the ZIP...
I'm also working on a beige G3 these days and was wondering about this connector :
- there are to bays in the top plastic for an FDD, but the Apple floppy cable is only single device ? (on my LC there are 2 of those connectors).
- maybe apple was thinking to have a double floppy option and for...
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