SWTPC 6800

Brent Hilpert hilpert at cs.ubc.ca
Wed Aug 17 10:56:59 CDT 2016

On 2016-Aug-16, at 9:55 AM, Brad H wrote:
> Thanks Brent.  So when I hit the end of an 'S' record line.. is it just a
> Line Feed I need to go to the next?  Or just type the next S record right in
> behind it?

Either should be OK, an S record is terminated by the number of bytes in the byte count field and
the monitor should be ignoring CR/LF in-between S records.

> Also curious about how you type S records at the monitor prompt.  I'm
> reading and trying to figure out how to do that.

In the same manner as being discussed, after starting an L command.
You typically aren't going to want to formulate your own S records other than as an exercise,
the point was just that it is possible - it's all just ASCII text.

Bill's method, of executing an M command from a text file, achieves the same thing: filling memory.
Something it's missing versus the S-record/loader format method is a checksum or any data check.
One may may not be concerned about line noise over a short RS-232 line, but if there are problems like
dropped characters, receivers overruns, framing errors, etc., due say to speed or line config issues the
M command method isn't going to tell you about it, while the S-record method will/should (in most cases)
report a data error.

> Many thanks!
> Brad
> -----Original Message-----
> From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Brent
> Hilpert
> Sent: Tuesday, August 16, 2016 9:29 AM
> To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org>
> Subject: Re: SWTPC 6800
> Yes, the monitor just sees bytes coming at it, it can't distinguish whether
> they're typed or coming from a host/machine,  as long as the byte sequence
> accords with the Motorola S record format.
> You can formulate your own S records and type them at the monitor, too.
> On 2016-Aug-16, at 9:09 AM, Brad H wrote:
>> Another question if I may -- for a short TXT loader file.. could I 
>> manually enter the information contained therein with my terminal?  
>> I'm just thinking for a quick memory test, etc -- it'd be six of one 
>> half a dozen of the other in terms of time to hook up a PC terminal and
> send the file..
>> If I were to hit L to put the 6800 into load mode, could I then just 
>> type out the contents of the loader file with the CT1024's keyboard?

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