[PATCH 1/3] ARM: driver for the character LCD found in ARM refdesigns
linus.ml.walleij at gmail.com
Wed Jul 7 08:32:43 EDT 2010
2010/7/7 Colin Tuckley <Colin.Tuckley at arm.com>:
>> The 4bit mode is the only one that seems to work. I tried putting
>> the display into 8bit mode and failed miserably.
> I've had a check with the hardware guys. Our self-test software uses the
> 4-bit mode, the 8-bit mode is untested.
OK I can make another round. I modeled the 4bit mode after
the ROM selftest actually.
The phenomenon is like commands go through in 8bit but not
characters, so whatever you write into CHAR_DAT only the 4 higher
bits go through, often with the effect of letters like "@@@@@" in
the display (if you write something with big letters).
>> The IRQ is stated in the reference manual as "don't use" because it
>> is "reserved for future use" but I implemented it anyway.
> The answer seems to be that "future use" means "for an OS".
Aha OK, then it's all mine! :-)
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