[Coco] BIGGEST PROBLEM
dave at davebiz.com
Mon Mar 6 15:22:29 EST 2017
I *think* there are four bus speeds that can be utilized by USB and 9600
is not one of them. I doubt very much that you would ever be able to do
USB communications bit-banger style with a 6809 or even a PIC or 8051
for that matter. You need a USB controller chip and that chip will
handle the different data rates. I have a book entitled */USB COMPLETE
Fourth Edition - The Developer's Guide/* which explains a lot. The book
is 500 pages long and I've had it for some years. There may be a newer
edition out but this one which was last revised in 2009 covers USB 3.0
and USB OTG.
On 3/6/2017 2:03 PM, John Guin wrote:
> Can USB slow down to 9600 baud? I know on the Arduino for the serial monitor (and serial connections in general) you set the speed to 9600 to 115K or so.
> I could not find a minimum speed for USB documented anywhere, but saw that you could connect older 9600 baud modems via USB. Seems like that would be do-able if this is the case.
> -----Original Message-----
> From: Coco [mailto:coco-bounces at maltedmedia.com] On Behalf Of Dave Philipsen
> Sent: Monday, March 6, 2017 11:52 AM
> To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> Subject: Re: [Coco] BIGGEST PROBLEM
> 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
>> 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.
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