I am using the Accutron prototyping board with the ADuC841 controller to develop an application that converts voltages to power to display power, VSWR and temperature and displays the results on a 4 line LCD display. Everything was working ok and I was getting through the project quite happily writing code, downloading it and checking the result. After about two weeks of this I downloaded code and the display was blank. I pressed the reset and rubbish appeared on the screen. After repeated presses of the reset button eventually I got the correct display and from that point everything worked ok until either another reset or a download. It is as if, when resetting, it is not always vectoring to the correct location to start. Does anyone else have experience of this strange behaviour and why it should suddenly start after working ok initially?
1) what kind of reset - hopefully not RC 2) could very well be (an) uninitialized variable(s) what debugging tools do you have? JTAG/ICE etc
I am using the Accutron prototyping board which I'm sure some will know what is, I do not
Erik
The development board is nothing special, just an 841 with a serial interface for downloading. Debugging is by software! I put in leds or messages on the lcd to see what is happening!
Actually, while reclining in my bath this evening I had a thought - I once tried to utilise the BUSY flag of the lcd display for getting the write timing correct. That did not work so I reverted to using delays (horrible I know). It occurred to me that I have left the R/!W pin connected to a port rather than connected to supply ground. This could well account for the erratic behaviour and will be investigated tomorrow. I will let you know the outcome.
Sorry, I forgot to add that the reset is via a button on the board and is tied to a suitable level - no not RC, I don't do that.
Doh!! And guess what, I was right. Tied the R/W line to ground and everything behaves perfectly again. Hey-ho, the things we dream up to waste our time.