Jardine Electronic Services
Microprocessor Experience

Original MC6800L eval kit from Motorola: "a Computer on a Card", 1975

This first piece of actual hardware that I had my hands on was the Motorola MC6800, the great-grandfather of all of Motorola's second and third generation chips.  The plastic-wrapped card above was part of the MEK6800D1 Evaluation Kit and contains the MC6800L (date/die coded PK7548 D), which is in a 40-pin DIP pack.  The necessary peripheral chips to even begin communicating with the 6800 are: MCM6830L7, a 1024x8-bit ROM containing the MIKBUG loader program; 2 - MCM6810L1, 128x8-bit RAM chips, giving a total of 256 bytes of program (less stack requirements!); 2 - MC6820 PIAs or Peripheral Interface Adaptors which expanded the 8-bit data bus to handle four separate 8-bit peripherals; MC6850 ACIA (Asynchronous Communication Interface Adaptor) or UART, for RS-232 interfacing.  Missing from this card but required for higher communication rates was an MC14411 Bit Rate Generator.  Using the software in MIKBUG one port on one of the PIAs was activated as the RS-232 connection and the baud rate was handled by wait loops in the program ROM, which was perfectly acceptable for the I/O wiring shown in the book: to a standard 110 baud Teletype terminal.

CPUs I've worked with...

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