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Subject: LCD code for recorder
From: Gary Czvitkovicz (gac_at_usa.com)
Date: 2001-12-29


Hi all,

I've been lurking on the mailing list for a bit, and I find the project very
interesting. I have an AJBR, and I'd love to help hack some better firmware
for it. Thanks for all the good work that's been done so far.

Anyway, here's my first contribution. I've worked with the LCD controller
used by the recorder on another project, so I've put together some code to
drive it.

Just the basics for now. It displays ASCII strings using 5x8 pixel
characters. The code generates it's own characters, since the display is
just pixels and has no character generator of its own.

The code keeps a copy of the display bitmap in memory, and updates the
entire display at once. This makes it easier to do things like put
characters at non-byte boundaries, and maybe in the future, use bigger fonts
and do simple graphics. The test code blinks the LED every 64 screen
updates, and it gets about 20 updates/second.

Any info on the display used on the AJB6K? From a quick look at the
disassembled firmware, it seems like a different controller, but it uses a
similar serial data protocol. It seems to take ASCII characters directly
and does it's own character generation.

BTW, here's how the CPU pins appear to be connected to the LCD controller:

CPU AJB AJBR
--- --- ----
PB0 DC SDA
PB1 CS1 SCK
PB2 SDA DC
PB3 SCK CS1

The attached ZIP file has the C source code and the AJBREC.ajz file, which
works on my recoder. Also included is a modified version of scramble.c that
pads out to 51200 bytes and a multiple of 4.

Happy new year,
Gary
gac_at_usa.com





Page was last modified "Jan 10 2012" The Rockbox Crew
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