[GreenKeys] Model 15 C-64 rate question

[WA5CAB--- via GreenKeys]

I haven't played with any Commodore equipment since I switched to CPM III 
and then MSDOS in I think the late 80's. But if the 8-bit byte is clocked out 
at the proper bit rate, you just program two STOP bits into the 7th and 8th 
bits of every byte. The normal for 60 WPM TTY is actually 7.5 bits or 
units. The START and 5 DATA bits are each 1.0 units long. The STOP bit is 1.5 
units long, for a total of 7.5 units. If each byte is 8.0 units long, the 
machine will run just fine but at a nominal 56.25 WPM. ((7.5/8)*60).

Robert Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480

In a message dated 07/05/2015 21:49:55 PM Central Daylight Time, 
drlegendre at gmail.com writes: 
> John,
> 
> Ok thanks - but a couple of things, here..
> 
> 
> From what I've read, those "user" baud rates (in the third and fourth 
> command bytes) are supposedly not implemented. There was intent to do so, but 
> the functionality isn't there.. or so I have read. Also, I'm pretty sure the 
> string needs to be sent as CHR$(244)+CHR$(16)+CHR$(139)+CHR$(43) vs. 
> integer values in ACSII. 
> 
> 
> But setting all that aside, I can't see how the TTY will cope with the 
> character frames sent by the C-64. I see that you are setting 5 DATA bits and 
> 2 STOP bits, but isn't the frame still 8 bits long (including 1 START bit)? 
> Isn't the TTY code 5 DATA bits plus 1 each STOP and START, for a total of 
> 7 bits?
> 
> 
> Seems like they'd fall out of sync after the first character. Last bit of 
> the first character sent from the C-64 would become the first bit of the 
> next character for the TTY, wouldn't it?
> 
> 
> 
> 

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