Altair Binay Clock?

[gio74]

I was thinking that I'd love to make a binary clock with the Altair,
do you guys think it would be possible to use A15 to A8 as a display?

[AltairClone]

Yes, with a small program running at zero, you can make the upper 8 address lights display pretty much whatever you want using the same technique as "Kill the Bit" or my front panel "Pong" program. These programs are both in the "Front Panel Programs" folder on the support page.

Mike

[gio74]

ah great Mike, I supposed the answer was there..
thank you so much.

[gio74]

if anybody wants to help me I'd be grateful, my assembly is still that of a noob :P

[AltairClone]

The Altair Clone includes the 88-VI/RTC board from which you can get 60hz interrupts, or another neat trick is to use a serial port and just continually transmit characters into the air as a timebase. For example, on a 9600 baud serial port configured for 8N1, you'll get an OK to transmit bit 960 times per second. This gives you just over a millisecond to go update lights, do some housekeeping, etc., before you come back to wait on the UART to sync again.

Mike

[mail@gabrielegan.com]

Mike, that's fascinating about the serial UART. Presumably, the timing works like that because 9600/10 = 960. I can see that 8N1 gives 9 bits -- where's the 10th bit coming from? Is there a default start bit for each byte? (I've always wondered how serial comms does synching and found the technical manuals too hard to make sense of.)

Regards

Gabriel

PS I've been meaning to get back to your excellent assembler program for bit-swapping elsewhere on the forum -- just got to finish another project first.

[AltairClone]

Yes, there is one start bit, eight data bits, one stop bit, for a total of ten bits.

Mike