 Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me. |
Forum Index : Microcontroller and PC projects : Addressable PicoMites
  Page 2 of 2 |
|||||
| Author | Message | ||||
| PhenixRising Guru  Joined: 07/11/2023 Location: United KingdomPosts: 1285 |
Heck, what is wrong with me  All of my existing UART comm's are Full Duplex, differential transceivers and they have, wait for it.....ENABLES This is all I need to do (I think) and then get creative with how to make the node-of-interest, active:   |
||||
| dddns Guru Joined: 20/09/2024 Location: GermanyPosts: 452 |
Looks promising, happy tinkering :) |
||||
CaptainBoing Guru Joined: 07/09/2016 Location: United KingdomPosts: 2163 |
I think you don't need to worry about the enables. If you have everything active and just establish some ground rules (a protocol) then everything will live nicely. yours is a wired version of a wireless network. I did a star on several installations of a snooker table manager using scores of HC-12 433MHz modules hidden in the ceiling roses of the lights over the tables (and a few other exotics). Each had an address and only the master could initiate conversation (to prevent collisions) and the protocol kept everything tidy. In the production kit, I took this a stage further with multi-channel wireless on some devices to act as proxies and cover blind-spots. That got complex but it worked - would recommend "flatness" of your network Each slave ran identical software which was really nice, configured at install time and saved in Flash. Incidentally, this was the point I moved into the abyss because versions of MMBasic after 5.0408 erase the flash when you load your prog... I just couldn't do the re-config on 200 modules just because I uploaded new software... but 5.0408 is rock solid so I am not complaining.write-up here with working code. And here is a vid of two micromites, and a MMX all talking to some VB on my laptop (the master) actually doing it with that protocol No reason the same thing wouldn't work on wired multi-drop - the transmission medium is irrelevant if you consider the protocol only wants the data to move reliably. In my SIL module, I have made provision for multi-drop with a single diod and it work with a similar protocol really well over small distances (few metres - it's only 3.3V). The key really is having a layer of your software over the comms port, then you can do it on the cheap if you don't want to use hardware modules h Edited 2025-05-18 21:08 by CaptainBoing |
||||
| PhenixRising Guru Joined: 07/11/2023 Location: United KingdomPosts: 1285 |
This is a bit different, bud. Yes, my standard 4-wire multidrop works as you described although I do use the TX enables on the slaves whereas the master has RX & TX permanently enabled. But what I'm looking at here is a way to have one console connection talk to multiple slaves, albeit one at a time. If I need to edit the code, etc. on a particular node, I want one connection but be able to talk to the selected node. All other nodes (PicoMites) need to be totally isolated from both TX & RX.  |
||||
Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7746 |
But he won't listen to me 'cos I'm too ancient. ;) Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
||||
| PhenixRising Guru Joined: 07/11/2023 Location: United KingdomPosts: 1285 |
Au contraire  It was your suggestion that reminded me of the enables which are effectively the same thing. Obviously, you weren't to know about my transceivers. No, the thread was useful. Relays and UTFN  |
||||
| Volhout Guru Joined: 05/03/2018 Location: NetherlandsPosts: 4982 |
Phenix, They call that MODBUS (RTU / ASCII). You do not have to use RS485 hardware interface. Your RS232 multidrop will also work (short distance). MODBUS is designed to be addressable and robust (CRC). I have already writen a MODBUS RTU master. And a MODBUS spy, it would not be too hard to also make a MODBUS slave running on a Pico, since all the blocks already exist in the master. Volhout PicomiteVGA PETSCII ROBOTS |
||||
| PhenixRising Guru Joined: 07/11/2023 Location: United KingdomPosts: 1285 |
Hi Harm, You missed it This is about using one console/terminal connection for a string of PicoMites. Need to select/isolate the devices. My main control network is separate. I have chosen Network Modular Control (NMC) for the control network, due to better efficiency: |
||||
| Volhout Guru Joined: 05/03/2018 Location: NetherlandsPosts: 4982 |
OK, thanks. Just to throw an idea. Although the Checksum byte is actually the sum of all bytes in the message, and it is simple to calculate, it may be faster to use a CRC8 in MMBasic. Calculating the CRC is 1 instruction. Not a loop.... Volhout PicomiteVGA PETSCII ROBOTS |
||||
| PhenixRising Guru Joined: 07/11/2023 Location: United KingdomPosts: 1285 |
Great idea, I'll test it. It's really awesome how we have these built-in features I want to test the ModBus system to be compatible with existing hardware. I just recently adapted a VFD/Flux-Vector drive to a Bridgeport milling machine. This is amazing value-for-money and boosted the performance of the mill. It is ModBus compatible (I am driving via DIO, though) and so I was planning to experiment with it. Unfortunately, as soon as I started and tested the machine, the production guys became excited and now it's busy full-time. I will purchase another of these devices. In fact, for <£50 (2.2KW), I might install one on every one of our machines. |
||||
| Page 2 of 2 |
|||||
 Print this page |
 |
The Back Shed's forum code is written, and hosted, in Australia. | © JAQ Software 2025 |
