[vcf-midatlantic] Happy owner fo a Tandy MC-10

Jonathan Gevaryahu jgevaryahu at gmail.com
Mon Jan 21 01:49:08 EST 2019

On 1/19/2019 11:23 AM, Neil Cherry via vcf-midatlantic wrote:
> On 1/19/19 9:06 AM, Duane Craps via vcf-midatlantic wrote:
> ...
> 6800 family, binary compatible
> 6800 - microprocessor
> 6802 - 128B of RAM, (microprocessor)
> 6808 - No ROM, No RAM (microprocessor)
> 6801 - ROM, RAM, IO (microcontroller)
> 6803 - RAM, IO, No ROM (microcontroller)
> 6809 - different microprocessor, mnemonic super set (not binary 
> compatible)
> ...

I'll add a few entries to your 68xx cpu/mcu list:

6804 - different incompatible microcontroller from 6801, slow serial 
ALU, 64 byte RAM, 3 I/O ports with DDR, mask ROM only, very rare/obscure 
(made for only a year or two), cannot execute from RAM, this is usually 
lumped in with the 6805 as the 6805 was far more popular.

6805 - microcontroller, same opcode set/compatible with 6804, but with a 
fast parallel ALU, both mask ROM and EPROM (with self programming!) 
options, and can execute code from RAM; spawned the extremely successful 
68HC05 and 68HC08 series later on. Several pinouts (28, 40) were 
available of the 6805, some with built in ADC ports and up to 4 I/O 
ports. 6805s were extremely popular early 8-bit embedded systems 
devices, used in diverse spaces such as motor controllers for the 
heathkit hero robots, alarm keypads, computer keyboards for row/column 
scanning, protection devices on arcade games, key scan controllers in 
synthesizer keyboards, automotive uses, and likely on thermostats and 
alarm systems, etc. The 68hc05 descendants were used in too many places 
to count, including all of the above, plus the cd servo and slave mcus 
on the CD-I game console, the EGRET, CABOOSE and CUDA chips which manage 
PRAM on later Mac II series and other old and new world Mac machines, 
the CD MECHICON on the Sony Playstation, etc.

68HC11 - microcontroller descendant of the 6809 but not binary 
compatible, much more powerful than the 68hc05 and 68hc08 series 
opcode-wise, but not as powerful as a 6809 or 68000. Has internal RAM, 
and either ROMLESS, Mask, EPROM or Flash ROM. This spawned the 
backwards-compatible (I think?) 68HC12 with added fuzzy logic opcodes 
and related features. These were popular in the automotive sector, as 
well as on some test equipment. The 68hc11 was also used on the MIT 
HandyBoard, a direct ancestor to the Lego RCX MindStorms bricks (the 
latter are H8/3292 based).

Jonathan Gevaryahu
jgevaryahu at gmail.com
jgevaryahu at hotmail.com

More information about the vcf-midatlantic mailing list