[Coco] Copying zip file from the sdc card

RETRO Innovations go4retro at go4retro.com
Fri Apr 24 21:02:10 EDT 2020


On 4/24/2020 6:08 PM, Allen Huffman wrote:
>> On Apr 24, 2020, at 6:01 PM, Gene Heskett <gheskett at shentel.net> wrote:
>> Unforch the 16550 needs a block of 16 addresses for all its control
>> registers.
> How did the 1990s 16550 interfaces work, I wonder?
They just mapped in 8 IOs.  The old OS9 descriptor would tell where.  
But, since I think you can mod a descriptor, folks are aware (I hope) 
that Ed's MegaMiniMPI has a 16550 (I think 2 of them) on board.
>
> Rick “CoNect” Uland popped up recently, so maybe he can shed some light.
>
> If someone will get me an Arudino mapped into I/O space, I can give you a buffer and flow control and all that, and it will still act like a 6551 to the CoCo ;-)

I can guarantee you that you will not, but I have an arduino mapped into 
the I/O space in CoCoDuino.  And, even at 20MHz, I can attest that 
writing a byte to the Arduino is only possible if you extend the write 
timing significantly, and reads do not work at all at 1.78MHz.  If you 
want to upgrade to a RPi Zero or esp32 or Onion Omega 2, maybe 
integration will work, but I have emperically verified the AVR will not 
(I tried exactly what you are describing.  FAIL, even when written in 
hand optimized ASM).

Jim



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