Dave Philipsen dave at davebiz.com
Mon Mar 6 14:51:43 EST 2017

I'm sure a 6809/6309 could handle USB.  If the 8051 can do it, the 6809 
can do it.  However, I have heard that some of the 8051 variants have a 
built-in USB controller that offloads some of the work.  I don't believe 
you'll find a 6809 with this so you'd likely have to use a 
USB-controller chip (sort of like a fancy UART) to get the job done.

It's sort of like doing serial I/O with a real UART as opposed to the 
bit-banger port.  The bit-banger method pretty much requires all of the 
CPU's attention at higher bit rates while a real UART chip offloads the 
detailed work.


On 3/6/2017 12:16 PM, RETRO Innovations wrote:
> On 3/6/2017 10:03 AM, camillus gmail wrote:
>> Hi All,
>> I was wondering, if a single 6809 or 6309 can handle USB protocol. If 
>> this could be done then a second cpu would be easy to imply in the 
>> exsisting coco's., and act as a dedicated USB controller ( does not 
>> have to be a 6809 but like to stay in the era )
>> There are cpu/controllers with build in USB support.
>> - for the keyboard, this cpu can halt the main cpu to put characters 
>> that ist get from the usb board, directly in the characterbuffers of 
>> - for mouse/ joystick I think something similar can be done.
>> I don't know I'm just a thinker...LOL
>> But it would be not the first time someone made a big invention from 
>> someone else s idea's  ...lol
>> CB
> I don't know that a 6309 can (for the performance reasons folks note 
> in other places), but there is a period-like device that has been 
> blessed with USB support:  the 8051.  You can do a search and there 
> are a host of 8051 variants that have built in USB.  Not sure about 
> HOST or OTG support, but I have to assume they have it.
> I know everyone on here is probably biased against Intel, but the 8051 
> line (which is no longer produced by Intel, as far as I know, but it 
> is their architecture) has led a very active life. Atmel and others 
> make 8051 variants and lots of stuff runs 8051 code.
> Jim

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