Re: Program LCD HD44780 with 68HC11 in Handyboard
- From: "John B" <spamj_baraclough@xxxxxxxxxxxxxxxxxxx>
- Date: 27 Oct 2007 16:06:39 GMT
On 27/10/2007 r_spaargaren@xxxxxxxxxxx wrote:
Hello,
for a school project i need to program the Motorola 68HC11 to use the
HD44780 LCD controller, and this must be done in C lang plus maybe a
bit of assembly.
The 68HC11 uC is embedded in a HandyBoard (www.handyboard.com).
The Handyboard gives the following problem:
The Handyboard has different modes, Expanded mode and Singe chip
mode.
In Expanded mode the peripheral databus is connected to the external
ram. The same databus which connects the uC to the LCD.
In Single chip mode the uC is connected to the LCD but the external
cannot be reached. In fact, as far as the 68H11 is concerned, there
is
no external memory anymore. So it can no longer execute a program
from
its external RAM. It only can use its internal RAM.
So the solution must something like this:
- Start in Expanded mode and launch main program.
- Copy LCD-program from external to internal RAM (routine that
includes initialisation).
- Switch to Single chip mode.
- Execute LCD program which initializes the LCD
- Switch back to Expanded mode
- Copy the string or char I want to print to the internal ram.(Method
with parameter?)
- Switch to Single chip mode
- Write string or char to LCD
- Switch to Expanded mode.
- Continue with main.
The problem is that i dont know how to send the LCD program to the
internal RAM when I'm in Expanded mode.
So the question is: "How do I load a piece of the C code, which
includes the initialisation and later the function with parameter,
into the internal ram?
I hope you understand my problem! If not, please tell me and i will
try to clear things out.
Thanks in advance :)
P.S. I'm dutch so my english is not fluently, sorry for that
Firstly have a look at the schematic and see how the MODB pin is
connected, then read the HC11 manual to see what this means. Once you
have understood the meaning of "Special MCU Operating Modes", you can
rethink your proposal.
It would also be a good idea to look at the extensive range of software
examples at the URL you gave us.
--
John B
.
- References:
- Program LCD HD44780 with 68HC11 in Handyboard
- From: r_spaargaren
- Program LCD HD44780 with 68HC11 in Handyboard
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