 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 : Micromite losing its memory
| Author | Message | ||||
| Lee3 Regular Member  Joined: 17/09/2014 Location: AustraliaPosts: 57 |
I recently dismantled most of the components from a micromite board and repurposed it (needed the LCD display, and was feeling too lazy to wire up another).... It seems to be working normally, BUT - twice now it has seemingly spontaneously lost its program memory - ie the BASIC program I've entered vanishes, and the chip of course, does nothing. Once it happened when I was testing the effects of low voltage on the circuit and its power supply - I lowered the input voltage to its power supply board enough to cause the 3.3V/5V output to drop. When powered back up it was blank.... Now today, I've gone back to the chip after it has sat on the bench for the week (powered off), and it is again blank. Can anyone offer thoughts on where to begin with this?? Cheers Lee |
||||
Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9610 |
Power supply is my first thought. I assume you have 100n decoupling caps on BOTH 3v3 supply lines, right by the chip? Within 10mm ideally, of the power pin on the chip. 47uF Tantalum or 10uF X5R MLC for Vcap? (also mounted as close to the Vcap pin as possible) When you say it is 'Blank' do you mean the program within MMBASIC has gone, or the BBMASIC interpreter has also gone? IE: If the former, you will still be able to talk to it using the console, but the program memory has vanished. Try another chip. If you have used that one for several experiments, it might have developed a problem. A virgin chip will eliminate that issue. If it still happens, something else is causing it, but you have then at least ruled out the chip as the source of the problems. I have used hundreds of MM chips now, and I have never had one lose it's memory. Not to say this can't happen, as it has obviously happened to you, but it just has never happened to me. Micro-controllers don't like any kind of dirty power supply, so this is definitely where I would be concentrating my investigation at this point. Smoke makes things work. When the smoke gets out, it stops! |
||||
MicroBlocks Guru  Joined: 12/05/2012 Location: ThailandPosts: 2209 |
The older (+-3 years) version of Mmbasic did have a problem with that. Make sure you have the latest. Microblocks. Build with logic. |
||||
| Lee3 Regular Member Joined: 17/09/2014 Location: AustraliaPosts: 57 |
Thanks.... Not sure at present what caps are on the board (built according to specs in Micromite manual).... MMBASIC program gone - the chip appears in the console, and can be programmed, but typing 'edit' brings up a clean screen.... and then it appears I can't be too sure how long the program will last.... |
||||
| Lee3 Regular Member Joined: 17/09/2014 Location: AustraliaPosts: 57 |
It's an older one.... 4.5D I think.... I did buy a MIcrobridge, but then yesterday started to build it and fragged soldering the SMD pins for the micro-USB port.... I went to Jaycar and picked up an Arduino starter pack, I don't have time to rebuild from bare boards all the time.... :( |
||||
palcal Guru Joined: 12/10/2011 Location: AustraliaPosts: 1993 |
With 4.5D that would be a 150 chip. Things have come a long way since then. I would get an E28 from Grogster E28 US$12, cheap as chips, pun intended. Paul. "It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all" |
||||
| robert.rozee Guru Joined: 31/12/2012 Location: New ZealandPosts: 2442 |
you can just take a spare USB cable with a type A plug on the end and solder wires directly onto the 1455 as follows: BLACK to pin 14 of 1455 green to pin 13 of 1455 white to pin 12 of 1455 RED to the +ve end of the capacitor (+5V) next to the LED note: i may have green and white swapped. if it doesn't work, try them the other way round. no harm will be done. cheers, rob :-) |
||||
TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 6283 |
4.5D was produced for the MX150 as well as the MX170. It was the last for the MX150. Jim VK7JH MMedit |
||||
| isochronic Guru Joined: 21/01/2012 Location: AustraliaPosts: 689 |
I would check it is active (on the two clock pins, a cro is best but otherwise a good multimeter should show some middle voltage), after that try to see if /what anything is left in the flash memory. |
||||
Geoffg Guru Joined: 06/06/2011 Location: AustraliaPosts: 3292 |
Ver 4.5D did suffer from accidental resets to "factory default". This was caused by the console Tx and Rx pins appearing (to MMBasic) to be shorted together at power up. If you have a MX170 you can upgrade to the latest version which fixed that particular vulnerability. If you have a MX150 you cannot upgrade so you will have to take care with the console's I/O pins. Geoff Graham - http://geoffg.net |
||||
| Lee3 Regular Member Joined: 17/09/2014 Location: AustraliaPosts: 57 |
Thanks for the replies.... I've set it aside for now.... I can say that I certainly prefer MMBASIC over Arduino C..... :D |
||||
 Print this page |
 |
The Back Shed's forum code is written, and hosted, in Australia. | © JAQ Software 2025 |
