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GMC75X Credit Card Microcontroller


Product Summary


I2C programming
and/or expansion

  GMC75X picture   Optional I/O
connector and
proto area

GMC75X Microcontroller
(Atmel AT89C2051 version)


Ideal for those small jobs where a
standard embedded controller
can't be justified.


The GMC75X is like a "BASIC Stamp" except that you can program the module in 'C' using C-FLEA and a download cable. Alternatively, use 8051 assembler (you will need a programmer for the CPU though!).

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Key Features

Note: You can't program any of the CPUs in the GMC75X - you can only download to the on-board EEPROM. 

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CPU Selection

For speed, use the 87C750 (available up to 40MHz). 11.0592MHz is standard.

For analogue I/O, use the 87C752 or 87C749 (5 x 8-bit A/D + PWM) or the 89C2051 (analogue comparator).

For I2C slaves, use the 87C751 or 87C752.

For a hardware UART, use the 89C2051.

For quick re-programming, use the 89C2051 with 2k of Flash program memory.

For more RAM, use the 89C2051 with 128 bytes (the others only have 64 bytes).

For most I/O, use the 87C749 or 87C752 (2 x 8-bit ports + 1 x 5-bit port).

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  Exempt GST Including 10% GST $US
Bare board with user manual $13 $14.30 $8.50
Full kit (no CPU) $36 $39.60 $23
Assembled and tested (no CPU) $45 $49.50 $29
89C2051 CPU (unprogrammed) $10 $11 $6.50
89C2051 CPU (with C-FLEA) $15 $16.50 $9.60

Credit cards accepted

Application Example
Just before Christmas 1997, our two daughters asked why we didn't have flashing Christmas tree lights? So later, while the girls were out shopping, I asked my son to wire up a few LEDs while I wrote some software for a GMC75X (89C2051). When the girls saw the tree, they thought it was great!

For Christmas 1998, we have been more adventurous and used a few more LEDs in the shape of a Christmas Star for a more spectacular result!

Christmas 1999 saw the Christmas Tree released as a kit.


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Last updated: 18 Jan 2008

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