Program LCD HD44780 with 68HC11 in Handyboard

[r_spaargaren]

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!

[Jack Klein]

On Fri, 26 Oct 2007 05:50:01 -0700, r_**********@hotmail.com wrote in
comp.lang.c:

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!

I need to tell you that you are asking in the wrong place. This group
discusses the standard C language, defined by an ISO standard, that is
completely independent of hardware. It says nothing about LCD,
internal RAM, or Expanded mode.

Ask this question in the group news:comp.arch.embedded, where this is
exactly the type of thing they discuss, and there will be people there
who are familiar with the 68Hcii and the HD44780 controller.

--
Jack Klein
Home: http://JK-Technology.Com
FAQs for
comp.lang.c http://c-faq.com/
comp.lang.c++ http://www.parashift.com/c++-faq-lite/
alt.comp.lang.learn.c-c++
http://www.club.cc.cmu.edu/~ajo/docs/FAQ-acllc.html

[Mark McIntyre]

On Fri, 26 Oct 2007 05:50:01 -0700, in comp.lang.c ,
r_**********@hotmail.com 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 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?

You don't load C code, you load the result of compiling this into an
executable format for your platform.

Unfortunately however the mechanism that a given h/w platform uses to
load something into memory, including how you copy it from another
platform such as a PC or switch between operating modes on the chip,
is entirely offtopic in this group. You are likely to have better luck
in a group specialising in embedded software development.

--
Mark McIntyre

"Debugging is twice as hard as writing the code in the first place.
Therefore, if you write the code as cleverly as possible, you are,
by definition, not smart enough to debug it."
--Brian Kernighan