Activity for Tom Uban
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Tom Uban posted a comment on discussion General Discussion
Sigh, I missed that in the docs, or at least I've forgotten it since I built the machine at the start of 2020. Thanks for your clarification.
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I have recently noticed a problem with the EEPROM save/restore functionality. As my program grew to exceed 0x80, I discovered that only the lower half of the program is restored after the program is saved, the board is powered off/on and the program is restored. I noticed this when I was able to load the program via serial and run the program without errors, but if the program was loaded, saved, the board powered off/on, restored and run again, the program would fail due to the upper half of memory...
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Awesome. I would recommend making it so that a set of wires leading from the PCB line up with the In0, In1, In2 (adding push buttons for the setting of time) as well as GND and +12v :)
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The computer primarily waits on the inwait instruction for a minute to pass and then does enough calculations to update the time. The inwait hold is managed in the PIC micro controller and so no relay sequencing is performed during the wait. Generally relay wear is based on contact cycles, not on time, but I guess time would tell. Load the program (clock2.asm) and try it out...
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I wanted to do something with my Relay Trainer which could run for an extended period of time, but not burn out the life of the relays. To this end, I created a clock which updates once per minute based on a simple circuit (clock_timer.jpg) which uses some CMOS parts (running at 12v) to create a 1/120Hz square wave driving the In0 input. The code displays the hours:minutes in the right four digits of the bigger display and also outputs the time on the serial console. Once running, the minutes can...
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I wanted to do something with my Relay Trainer which could run for an extended period of time, but not burn out the life of the relays. To this end, I created a clock which updates once per minute based on a simple circuit (clock_timer.jpg) which uses some CMOS parts (running at 12v) to create a 1/120Hz square wave driving the In0 input. The code displays the hours:minutes in the right four digits of the bigger display and also outputs the time on the serial console. Once running, the minutes can...
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Changing R204 to 1.8K has made the PC much more stable.
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After my coffee, my brain kicked in better and I realized that the silkscreen on the board might indicate which relays could be the problem. I swapped a couple a couple of times and it seems better now, but bit 5 still seems on the edge. I guess I'll keep fiddling with them if it contues to flake out, at least until I run through the few extra relays I purchased.
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The PC 0x00 vs 0xff worked properly after initial construction, but now it seems that bits 5 and 7 are not setting properly (as you suspected). Is there a drawing which helps locate the offending relays or do I need to find them in the schematic? Thanks much!
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Another sequence I am seeing is this: 14 e800_0007 inwait 0x07 B[07] <- 00 15 8408_2620 jsr 0x26, 0x20 A[26] <- 16 PC <- 20 20 4880_0104 inc 0x04 B[04] <- 01 PC <- 01 01 c810_ff00 halt halt In this case I stepped through and the JUMP light was not lit when the 'inc' instruction was executed, but the trace and next instruction clearly show an unexpected jump to 01.
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I began writing programs for my newly completed Relay Trainer using the serial console and I've noticed that the board is seemingly randomly executing a jump on instructions which should not jump. I am guessing that this is the JUMP bit either turning on unexpectedly or getting stuck on. An example of trace on output is this instruction: 22 48e0_3c06 rsbto #0x3c, 0x06 B[06] <- c5 PC <- 03 Any suggestions as to how to diagnose this are welcome. --tnx --tom
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My build it pretty much stock. I may add labels to the tops of the buttons as they are in a different layout than I expect. I did use 1/2" threaded standoffs with nylon screws to space the board off of the table, preventing the cut solder joints from scratching. I have an interesting (to me) project in mind and will post pictures once I am farther along with it...
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I recently finished assembling my board as well. I used the BOM to order parts from Mouser and DigiKey as suggested, substituting machine pin sockets (from Jameco) for the original side-wipe sockets. Aside from a brand new Jameco wall wort being DOA (fortunately I had another supply to use instead) and finding two sockets which were each only half soldered (flexing the board gave random results), it essentially ran "first time". I'm looking forward to experimenting with the serial port connection...
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