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ef1j91
October 27th, 2018, 01:51 PM
The behavior of my Sol-20 differs from that documented in the manual - presumably a mistake in the latter. The differences are in the parity bit settings and the total word length setting.

The manual states that S4-2 and -3 should be OFF and ON for 7-bit operation. I confirmed that it is the opposite on my Sol.

There also seems to be a mistake for the parity settings. The manual states S4-1 should be ON for EVEN and OFF for ODD. I have to set S4-1 OFF for EVEN parity.

Are these known errors?

Eric

deramp5113
October 28th, 2018, 05:31 AM
Yes, I noticed the same thing in the hardcopy manual with the Sol-20 I restored several years ago. See “Serial Port” on page 3 of my restoration document.

http://deramp.com/downloads/processor_technology/sol-20/hardware/Sol-20%20Restoration.pdf

I’ve seen newer versions of the manual online which have the errors corrected.

Mike

ef1j91
October 28th, 2018, 07:34 AM
Thanks, Mike! I probably read that in your writeup at some point, but I appreciate confirming. Those early machines were inscrutable enough at times, but incorrect documentation could REALLY throw you off. It makes for a fun time sitting down with an oscilloscope though, and nicely reinforces an empirical approach to knowledge.