Early Apple II Digital Scope and Spectrum Analyzer - Page 1
Forum section: electronics / testgear

author: mawyatt
author_rank: Super Contributor
timestamp: December 18, 2021, 04:48:22 pm
content: While cleaning out our attic we came across this ~1980 ET-1010A Digital Scope and Spectrum Analyzer from ETI. This was developed for the Apple II and used a PCB that mounted on the Apple II bus. Program was on a 5 1/4" Floppy Disk. Remember writing the baseline 6502 code in real time machine language, where we kept track of each clock cycle for each command. Very tedious and convinced me I didn't want to be a programmerWe sold these with ads placed in EDN and Electronics Design back then.Anyway, sometimes fun to dial back the clock and try and remember those early daysBest,

author: jrmymllr
author_rank: Regular Contributor
timestamp: December 18, 2021, 05:14:40 pm
content: That is cool. I see one chip on the board and two open DIP footprints. Apparently this one isn't fully populated?Many years ago (as a teenager) I designed a PCB for my Apple II using I believe some 6000-series VIA and an 8 bit ADC, ADC0803 or something like that, to do something similar. It never worked

author: ps
author_rank: Regular Contributor
timestamp: December 18, 2021, 05:26:16 pm
content: Quote from: jrmymllr on December 18, 2021, 05:14:40 pmThese are spare positions only. You can see the traces showing through, they only go to the solder pads next to them.The circuit consists only of the ADC connected to the data bus, ~DEVSEL and R/~W.

author: mawyatt
author_rank: Super Contributor
timestamp: December 18, 2021, 05:28:28 pm
content: Found old brochure!!Best,

author: mawyatt
author_rank: Super Contributor
timestamp: December 18, 2021, 05:32:33 pm
content: Quote from: jrmymllr on December 18, 2021, 05:14:40 pmThe open PCB area was for custom use. The ADC was directly connected to the Apple II bus and used the Apple memory, all timing was done by machine language routines that counted clock cycles, real PITAThe DIP switches set the range and address I recall, guess I need to study the manual I wroteBest,

author: mawyatt
author_rank: Super Contributor
timestamp: December 18, 2021, 05:39:19 pm
content: Quote from: ps on December 18, 2021, 05:26:16 pmYes this was as simple a hardware solution as possible, with only the ADC directly interfaced to the Apple II bus. The ADC output was direct write to the Apple memory.As mentioned the spare area on the PCB was used for custom work. Recall a customer that used the ET-1010A as a device to read and plot the temperature profile of a complex long temperature profile for a special plastic. The spare area hosted a multiplexer for the temperature sensor inputs.Best,

author: pcprogrammer
author_rank: Super Contributor
timestamp: December 18, 2021, 07:44:50 pm
content: Yes, them good old day's with cpu cycle timing. Was indeed fiddling to get timings right, but I loved it. Did not scare me away from programming

author: Tomorokoshi
author_rank: Super Contributor
timestamp: December 18, 2021, 09:04:24 pm
content: That's neat. I connected D->A and A->D converters to my TRS-80 Model 100.Now I'm working on restoring a couple Apple ][+ computers.

author: Electro Fan
author_rank: Super Contributor
timestamp: December 18, 2021, 11:37:50 pm
content: Quote from: mawyatt on December 18, 2021, 05:28:28 pmWow, you were years/decades ahead of time. You were seeing pretty far down the road. Very Cool!

author: mawyatt
author_rank: Super Contributor
timestamp: December 19, 2021, 01:22:59 pm
content: Thanks Tomorokoshi and Electro Fan, we also had an AWG that we never finished due to family issues that soon after dissolved ETIBest,

author: SeanB
author_rank: Super Contributor
timestamp: December 19, 2021, 01:40:43 pm
content: Looks like the DIP switches are there to configure the analogue input range and if there is a a voltage divider on the input or the reference source. Nice in that the Apple ][ gave fully decoded select lines per slot, so making decoding very easy.