Which 68HC11 version?

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Which 68HC11 version?

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meterman1980
Contributor I

Some time ago, I posted a question asking about the Motorola SC44125P CPU, and I eventually determined that it is a custom 6800 with pre-programmed, dedicated data bus (8 bit) and address bus (16 bit) pins, along with the 6801 instruction set. Although it has the option, neither the on-board RAM or ROM are used.

After some brief comparison of later 68xx CPUs, I see the 68HC11 comes closest, but want to know which would be a suitable version (or newer replacement) that would work the best.

Requirements:

6801 or 68HC11 instruction set
Ability to disable on-board RAM / ROM
Dedicated 16-bit address bus pins or the ability to easily program same
Dedicated 8-bit data bus pins or ability to program same
Support pins required: R/~W, Clock input (1MHz), ~IRQ, ~IRQ2, ~NMI, and ~Reset

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4 Replies

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celsoken
Contributor V

If you're attached to HC11 assembly code, maybe you could use a 9S12 to upgrade your design. At those ancient times it was said it was assembly source compatible, although object code was not compatible at all. You could check AN2708 which deals with External Bus Interface on the HCS12X.

Regards,

Celso

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466 Views
vicentegomez
NXP TechSupport
NXP TechSupport

Sorry all the HC11 is obsoleted 

 

So I can not recommend you any HC11 device.

 

If you want you can move to the S08 family like the mc9s08pb family

https://www.nxp.com/products/processors-and-microcontrollers/additional-mpu-mcus-architectures/8-bit...

 

I hope this will help you

 

 

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435 Views
meterman1980
Contributor I

Does it use the same opcodes as the MC6801?

I'm hoping to see if there's anything I can use without having to rewrite 16K of densely written assembly.

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vicentegomez
NXP TechSupport
NXP TechSupport

No, sorry, it does not use the same opcodes 

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