Start with the MC9S12 microcontroller family
Since the 68HC11 is not recommended for new design and also it starts to be difficult to buy certain versions,
68HC11 users can port their application on a 68HC(S)12(X) microcontroller family.Same programming model
There are many advantages for people who are familiar with 68HC11 to switch to 68HC12:
The 68HC12 family is compatible with the 68HC11 family at ASM source level
It has an improved instruction set and addressing modes
Low-cost development tools are available thanks to the BDM interface
High memory capacity: MC9S12DP512 = 14KB of RAM, 4KB of EEPROM and 512KB of Flash
XGATE DMA coprocessor is available in the S12X family
More memory and peripherals at lower cost compared to 68HC11
The point which could be improved in order to ease the C language portability is the banked memory: a 24-bit Program Counter supporting linear addressing would have been welcomed...
There are several companies which can provide boards based on 68HC(S)12(X) microcontrollers. I bought the CARDS12DP512 board from Elektronikladen.
I found at www.feaser.com a very interesting software package: Syn Code Editor for HC11 & HC12 which includes several examples in order to use the GNU C compiler for the 68HC12.
I ported the example hcs12dp256_noice to hcs12dp512_noice in order to use it with the CARDS12DP512 board and I added 3 basic functions to use the SCI interface.
Click here to download the zip archive containing all the sources and the makefile.
To summerize, you can start to develop with the MC9S12DP512 microcontroller at a minimal cost with:
CARDS12DP512 board = 107 €
Turbo BDM Light interface board = 28 € ( Please contact me if you want to order this board designed by Daniel Malík ).
GNU C compiler for the 68HC12 = FREE or Imagecraft Software ICCV7 for CPU12 Advanced = 349 $
NoICE debugger for the 68HC12 = 100 $
CARDS12DP512 and Turbo BDM Light
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