For comparison here is an original SWTPC MP-N board.
Reproduction MP-N bare board
The MP-N was introduced by Southwest Technical Products Corporation in 1977.
The Peripheral Technology reproduction board was reproduced to be as close as possible to the original. It does not have a solder mask or silkscreen.
This board does not work with 2MHZ processors, but it's possible that changes in the driver would allow it to work. The reproduction MP-N has only been tested with a 1MHZ 6800; it has not been tested with a 6809. It's probable that reassembling the driver would allow the MP-N to work with a 1MHZ 6809 processor.
From an SWTPC 1977 or 1978 Catalog:
MP-N Calculator Interface
The MP-N is a calculator interface board for the SWTPC 6800 computer system. This board makes it easy to do arithmetic functions within machine language programs while simultaneously conserving program memory. All necessary interface subroutine listings are supplied with the kit for maximum simplicity and ease of use. The interface uses the new National Semiconductor MM57109 Number Oriented Processor and features Reverse Polish Notation, floating point or scientific operation, up to an eight digit mantissa and two digit exponent, four register stack, memory register, trig functions, base ten and natural logarithms and overflow indicator. The 5-1/4" x 3-1/2" double sided, plated thru hole interface board plugs onto one of the seven interface card positions and is powered by the computer system's power supply.
Downloads
MP-N AssemblyInstructions.pdf Original SWTPC MP-N instructions
RPN Introduction - Understanding RPN
CALC1.TXT - Calculator Demo Program
We only have four of the calculator chips on hand. After those are sold, it's probable that we will only sell the bare board since the calculator chip is so hard to find.
| MP-N-Bare | MP-N Bare Board | $12 |
| MP-N-ASM | MP-N Assembled Board | $59 |