| STEbus projects [message #8267] |
Sun, 31 January 2021 06:05  |
beb
Messages: 10
Registered: October 2019
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Junior Member |
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| Interest for STEbus projects[ 4 votes ] |
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Yes |
 4 / 100% |
| 2. |
No |
0 / 0% |
Hi everybody,
around 20 years ago, I worked a lot on STEbus systems for my company. We were mainly making specific PLC for transportation and automation. STEbus was often seen as a "low-cost" version of VME (still alive nowadays by the way).
For those who don't know STEbus, a few interesting things to know :
- 8 bits only
- maximum 5 MB/s bandwidth
- 1 MB memory addressing space
- 4 KB I/O addressing space
- fully asynchronous, with handshake for slow peripherals
- compatible with Z80, 6502, 6809, 68K, 8086, 80188, 8052, etc...
I always preferred STEbus to ECB because it was not "Z80-centric", but everything a question of taste 
Officially, STEbus (also known as IEEE-1000) is not used anymore, official reason being that it was replaced by ISA and PC/104. Like ECB, STEbus is however still extremely interesting to use as it is simple to implement (a little less than ECB, however, because of the handshake lines, which requires only a 74LS74 to operate)
As I started to dig back in my designs - some are still in MS/DOS Proteus CAD format  - I also found that IEEE and IEC were still selling the STEbus specifications, asking 250 euros for it 
Right now, I am working on a 5 slots STEbus backplane, a universal FPGA board able to run as a Bus Master and Bus Slave, and also a Raspberry Bus Master interface. I plan to share everything on the wiki of course when I will have made enough progress (I work on the 3 designs in parallel)
If there is enough interest about it, I propose to create a specific entry on the wiki, as I have a lot of things to share that would be of interest for others (I also have the IEEE specification, but because of the copyright, I can not share it, but I can answer to questions about STEbus)
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| Re: STEbus projects [message #8268 is a reply to message #8267] |
Sun, 31 January 2021 10:34  |
beb
Messages: 10
Registered: October 2019
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Junior Member |
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Forgot to add the picture of the first version of the backplane PCB
I am still working on the power connector (not happy with this model of Phoenix) and I will also probably add decoupling capacitors on power supply of each slot
[Updated on: Mon, 01 February 2021 11:07] Report message to a moderator |
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| Re: STEbus projects [message #8277 is a reply to message #8273] |
Mon, 01 February 2021 11:02 |
beb
Messages: 10
Registered: October 2019
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Junior Member |
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Hi Phil,
thank you for your feedback.
Honnestly, I have never heard about "open source" STEbus boards - except the ones I am working one right now
However, I have some datasheets from Arcom with the schematics within, that I can share (but I have no idea of what copyright applies to them, even if Arcom stopped making them since 2000)
I like your proposal about the reset button, but I have to check back the specification, as I remember that there are some strange constraints for this signal.
Benoit
[Updated on: Mon, 01 February 2021 11:03] Report message to a moderator |
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