Design Book
Compatibility List
In Circuit Prog
Project Info
Peel Source


Commercial Div
University Div
Complete CV


In the normal development of any project or design there are changes before the next version is complete. This list applies to the board design variations.


Device Change Reason
U3 Add 100K resistor to pin 12 pull down to prevent floating
ISP keep cable very short, ~ 2 feet prevent noise
S1 rotate switch 90 degrees contact alignment
S2 rotate switch 90 degrees contact alignment
JP18 do not install misaligned & not used
DS1 remove 7-segment when use LCD use same control lines & mechanical space
Serial connector requires female  
C9 replace with wire not used with Max235 chip
Peel Pin 10 is WRn mislabeled
Peel Pin 11 is RDn mislabeled
U1 Pin 16 is WRn mislabeled
U1 Pin 17 is RDn mislabeled

Schematic & Peel

versions available at print time


The board has many options for further development and projects. The following items are not required for the current set of projects. 


Component Action Reason
LCD contrast place jumper from LCDCT to gnd contrast auto adjust not used
JP18 remove spare IO
RS485 remove using RS232 only
R11 replace resistor with wire EA' connect for internal only
RS232 handshake remove not used
GenMem remove components use internal memory only