6809 SBC

[CSquared]

Tony Duell wrote:
>> When I moved from the 6800 to the 6809 (in assembly language - *many* 
>> years ago) I was sort of astounded and at the same time very pleased by 
>> the way many of the little subroutines I had written for the 6800 became 
>> one instruction in the 6809.  I think it will always be my favorite 
>> 8-bit CPU.  My only annoyance at the time was the fact that there was no 
> 
> I was a confirmed Z80 hacker until I bought a CoCo 2 in a clearout sale. 
> And after reading the 6809 data sheet I fell in love with that chip.
> 
>> way for the software to reset the companion UART chip, whose number I've 
>> completely forgotten by now.  6821 maybe???
> 
> The 6821 is the parallel chip (2 16 bit perts). The serial chip, commonly 
> called te ACIA is the 6850. It needs an external baud rate generator. 
> There was also the 6852 synchronous serial chip and the 6854 which did 
> some other flavour of synchonous comms and was used in the Acorn Econet 
> system
> 
> Of course you could also use 6502-series I/O chips on a 6809 (and vice 
> versa), the buses are essentially the sane,. The 6522 VIA is a nicer 
> parallel chip (with counter/timers, a shift register, etc). The 6551 is a 
> serial chip with a built-in baud rate generator.
> 
> -tony
> 
Many thanks to you and Henk for reminding me what the Motorola "UART" 
chips were called/numbered.  All this discussion is making me want a 
CoCo unfortunately.  Never had one when they were "new" but always 
thought they would be a lot of fun - maybe a garage sale will turn one 
up some day.  Just what I don't need of course - yet another project or 
piece of hardware.
Later,
Charlie C.