2018-07-21
It’s alive! So it’s been a while. Basically when revision D of the PCB came in is when I tore my lab apart for a remodel. Well good news for everyone especially Neal (the dog) – the remodel is done and I’m back to pretending I know what I’m doing with a soldering iron. The major changes between revisions C and D of the board were the following. More details on each item to follow. Read more…
2017-12-30
Note: I was wrong in the last post. It’s the dsPIC that has a broken UART, not the PIC24. For the last month I have been doing the very unsexy work of grinding out bugs in the code. As I hinted at before my software stack had issues under load. I chose to test the full stack (hardware and software) by subjecting it to a completely unrealistic load. The logic behind it is that the Read more…
2017-11-18
I have been working on finishing up the software related to the board. The only feature that I had left on my wish-list was implementing the calibration stuff. The goal was to have the calibration offset be stored in EEPROM and for it to be adjustable via the text/cli interface and via the binary protocol. The process was going to touch the graphical interface piece, the middle-ware that sits between the interface and the board, Read more…
2017-10-08
Second board is complete. Here are a few pictures of the two boards mounted together. That’s total of eight ICTD inputs, eight 4-20mA current loop inputs, and eight digital outputs. Now I need to find something to control! Next update will be about yet another major screw up of mine.
2017-10-01
Today I was working on my power and serial expansion board for the Beagle Bone Black. This board provides 5VDC to the BBB, breaks out the RS-232 ports, and sequences (or is supposed to anyways) the power to the RS-232 transceivers and the IO board. All that because the BBB can not have any power applied to any of its input pins until a specific pin goes high indicating that the processor has found its Read more…
2017-09-30
How do I put this. Version 1 of the board is done. The pictures below is the first board assembled on the final revision of the PCB. It says revision C, but it’s really revision D. The only difference between C and D is that I made the holes slightly bigger for the drive FETs in the output over-current protection circuits. This batch I had manufactured by Elecrow (https://www.elecrow.com/). I’m fairly satisfied with the results. Read more…
2017-09-17
So I am going to go ahead and open with this. Those are the stats for the ‘LOGIC_CORE’ piece of the software stack. For those not fluent in gibberish, what this shows that after an hour of something like half-dozen threads grinding away at the IO board communicating with an “end user” process no memory errors have been encountered. No out of bounds writes, nothing was lost after allocation, etc. What this means is that Read more…
2017-09-09
It appears that I am incapable of taking a decent picture. I guess I am not perfect after all. All of the pictures below were taken at the same time. Well OK technically not at the same time; they were taken in a serial fashion. They were taken during the same picture taking session. Why some of them look like a teenage girl applied some sort of social media photo filter on them is beyond Read more…
2017-08-15
So it works. My IO board that has been in development for 7+ months works. The hardware works. Sure there are some warts that need to be addressed in revision C, but it works. It is functional. The firmware works. The CLI-style human interface works and the binary machine interface works. Sure there are some warts, but it works. The Linux portions, the multi-threaded, multi-process, bi-directional serial stack, and misc works. The human interface component Read more…
Revision B of the board PCB came in and has been assembled. All of the issues from revision A have been addressed. Did find a couple of issues in this revision though. I added microprocessor sanity checking circuitry and IC. It does not work at all. On the PIC24 it keeps rebooting the chip on the dsPIC30 it prevents the ICD3 from connecting to it. I will be ripping it out in rev C and Read more…