increment or decrement one of 16, 16-bit registers

Motorola's MC6809 was available in both clocking varieties - The 'E' suffix part number was the one with the external clock generator and two quadrature clock input pins (called E and Q). The non-'E' suffix part number had one clock input pin (EXTAL) and divided by four internally. E and Q were outputs in this case. A pin (MRDY) was available to freeze the divide by four counter to insert wait states.

It had an 8 bit ALU. 16 bit operations took two cycles, and the 8 x 8 multiply took 8 cycles.

I vaguely recall wire wrapping one of these as a hobby project in the early to mid '80s.

Regards, Allan

Reply to
Allan Herriman
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I vaguely recall wire wrapping!

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Rick C
Reply to
rickman

Found the patent for the 1801; it shows the increment unit as separate from the registers, and separate from the ALU. I would assume that if it's to be binding, the patent needs to reflect what's actually there, at least in the large:

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www.wescottdesign.com
Reply to
Tim Wescott

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