max6953 sample code

moritz · Joined: 13 Dec 2003 Posts: 7 Location: London

Has anyone used the max6953 to drive led matrix displays? I would be very grateful for some sample code to address the max6953 from a pic. I have difficulties understanding the protocol from the datasheets.

Many thanks in advance, Moritz.

StuH_CC · Joined: 07 May 2004 Posts: 16 Location: Shropshire, UK

Hi Moritz,

I've used this device very successfully with PICs, they work extremely well. I have a fairly complete, if a bit untidy, library of functions covering most of the features of the MAX6953 that you're likely to want to use. It was written for a PIC16F819 using CCS PCM 3.185, but it's nothing special and should be easily portable to another device/version.
I had thought about posting this in the code library section, but didn't think there'd be any interest. I know better now...

Update: I've now posted the code - I'll leave the clean-up to anyone who wants to do it, but it works as-is.

Stuart.

_Moritz · Guest

Hi Stuart, thanks for that, I'll have a look now. Meanwhile I've deciphered most of the data sheet and I've managed to use both the built in characters as well as defined my own. The only problem that is left to sort now are some strange artefacts on the matrix (one column is constantly on and one row is behaving erratically as well.) I hope to sort that out over the weekend. Thanks again, Moritz.

Guest · Posted: Sun Aug 29, 2004 10:05 am

May I know how to define own character (I've done so, but not quite sure of it) and most importantly to display it on LED? Thanks!

StuH_CC · Joined: 07 May 2004 Posts: 16 Location: Shropshire, UK

I've never bothered with it, but my understanding is that you have to write the base address via register 5, with most significant bit set, then write the 7 bit data to the same register with MSB clear. There are 120 entries, and the address register autoincrements after each data write, so the initial address only needs to be written once. Each 7 bit data write corresponds to a vertical line on the display, there being 24 user-definable characters.

the code might look something like:

Guest · Posted: Mon Aug 30, 2004 9:46 am

Hi! Stuart. Thank you very muchi... It's really a great help from you. Laughing

All this while, my problem is I don't know we can just call out the character by the code between 00-23. That simple until I started to
Embarassed

.

I tried very hard to look it out and was fall deep just to figure how to read out the font data from the address pointer position. Then how to display it.

You just help me jump out from the trap I made for myself... Idea

Thank a lot! Wink

Guest · Posted: Sat Nov 05, 2005 2:01 pm

Do you have a schematic that you can share with me on connecting the pic to the 6953? thanks

kender · Joined: 09 Aug 2004 Posts: 768 Location: Silicon Valley