PIC µController Blog 2008

Work was sucessfully completed on the breadboard implementation of the Traffic Light Junction Simulator and an attempt was made to transfer it to stripboard. The stripboard ended being started as the reverse of the planned stripboard layout! The second attempt was a lot more successful, and after correcting some soldering / layout mistakes, there were only 2 major faults remaining.

• The first fault concerns one set of 'lights' where the holder of the hex inverter that drives the LEDs is not soldered in properly. To resolder the chip holder into its correct place will be a major rework.
• The second fault is that one of the 2-4 decoders decodes 0x0 as 1x1x1x1 when the expected output is 1x1x1x0. This suggests a short somewhere, and 0x1, 1x0, and 1x1 are decoded correctly.

The next stage of the debugging is to transfer the IC parts of the circuit back to the breadboard and have jumpers from the breadboard to the stripboard. This may be tricky as the pins on the µcontroller have been mangled and re-straightened. To aid the debugging the µcontroller will need to be re-reprogrammed.

The 5^th Simple LED project, the Traffic Lights has been completed.

Work has started on the breadboard for 6^th Simple LED project, the Traffic Light Junction Simulator.

The answer to my problem RETLW is addressed by the Techical Article AN566.

Earlier this month (on the 11^th) I got this working. The problem was that I was not treating the pseudo-array (Table Read) as zero-based.

So that is the 4^th Simple LED project complete and working!

I have since started the breadboard for 5^th Simple LED project, the Traffic Lights.

I have re-considered the ARM and re-considered the AVR µcontrollers, and dismissed the notion. The ARM is too complicated, and the AVR seems harder to program.

Working on the PIC code for this, but it isn't quite working yet.

The problem might be with the µController as I moved RETLW instructions from ORG 0x100 to the end of the program and that seemed to sort it. I also re-worked the delay routine so that it worked as well.

So that is the 1^st, 2^nd, and 3^rd Simple LED projects complete and working!

I have progressed to the Flash Sequence 5 LEDs project and am stuck. It uses the TMR0 interrupt which I have demonstrated works by blinking a single LED. I have also demonstrated that each of the five output pins can drive an LED. The problem is when I try to control the output pins by using a RETLW look up table. The LEDs do not follow the expected pattern.

I plugged my µController into my unregulated DC supply and saw the anecdotal puff of smoke. RIP my first PIC!

I edited a page of this site using Microsoft Word. Big mistake as a lot of junk HTML has been added and the file formatting has gone.

I have built the 1^st Simple LED project! It works - woot, woot!

I have finally rebuilt my laptop PC, which I intend to use to program the PICs.

I will use the 12F629 for the LED flasher project. 12F's will also be used for the RS-485 network. The network will serve no useful purpose except to prove that I can do it.

I have also decided to move voltage regulation onto the circuit boards and have it closer to the 'consumer'. There is still a need for a 'bench' +5V regulated supply.

I have bought the PIC programmer from Quasar Electronics but I haven't fired it up yet.

I am also thinking of using a 12F for detection. So many ideas so little action!