Friday, December 11, 2009

Added LCD connector to DCO1 board

Just a small update on the Matrix 1000 editor and some thoughts.

I realized I need a way to test how I should handle LCDs. Either I'd put an LCD on a new module, since I am thinking of putting two together to test the "motherboard" addressing somewhat properly.
However, lazyness got the better of me and I decided to just add it to the DCO1-board even though I am not planning to include an LCD on that board. Anyway, it will be used for testing only so I guess it's OK. I had a couple of free addresses on the board.

Here's a couple of photos of the DCO1 board in its current state:

Sorry about the exposure. It's a bit tricky with the lamp reflecting the light in the copper :)

The board is really messy on the back side now and it's difficult to get to some places with the soldering-iron without melting a nearby wire insulation.

LCD plans
I'm going to use a 16-pin IDC connector for the LCD but I didn't want to put a box header on the board because they use up a lot of space around them and I didn't have a lot of space left. So, I just put 2x8 rows of pins. The friction from all those pins is enough to keep the connetor in place. The little trim potentiometer to the right of the pins is to adjust the contrast on the LCD.
This should be enough to let me try out some code to control an LCD at least, once I get the "motherboard" ready as well ;)

One thought that occured to me is that I might want to use a graphic LCD as well on the Matrix 1000 editor. However, I am afraid it will take too much I/O time so I am considering putting a dedicated LCD controller for that and perhaps something else as well. We'll see.

Microcontroller memory worries
I've also started to worry about the available RAM and flash space on the LPC2103 I'm using.
It's got 32kB flash and 8kB RAM. I've been wondering if I should have chosen the LPC2106 instead but it was missing some features, most importantly the "Fast GPIO" which means you can change the state of the IO pins in 4 clock cycles instead of 14 (or something like that) so it's quite a difference.
However, it seems that the new versions of the LPC2106, called LPC2106/01, does in fact have all these same features, including Fast GPIO.
I sent an email to Olimex (manufacturer of the dev board I'm using at the moment) and asked him if his LPC2106 headerboard uses the old or new version. He replied the next day and said he's got an order pending for the new 2106/01's which he should receive sometime in January.
So, I guess I'll wait for him to assemble some header boards using those and then order a couple of them.
With the LPC2106 I'll have 128kB flash and 32kB RAM instead. Quite a lot more. I hope that will be enough.
But, I'll just have to wait I guess. No worries though, as if I'm keeping it up in the current pace I probably won't need the new microcontroller until next winter ;)

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