This application note describes the construction of a
low cost serial programmer which uses a PC with a par-
allel (Centronix printer) port to control a PIC16C84.
This programmer has the capability of programming a
PIC16C84 microcontroller, and reading back internal
data without removing the device from the target circuit.
This feature is very useful in applications where
changes in program code or program constants are
necessary to compensate for other system features.
For example, an embedded control system may have to
compensate for variances in a mechanical actuator’s
performance or loading. The basic program can be pro-
grammed and tested during design phase. The final
program and control constants can be easily added
later in the production phase without removing the
microcontroller from the circuit.
Automatic software and performance upgrades can
also be implemented in-system. Upon receiving new
system software via disk or modem, a control
processor with the included programming code could
perform in-circuit reprogramming of other
microcontrollers in the system.
This programmer can load program code, part
configuration, and EEPROM data into the PIC16C84.
In read back mode, it can verify all data entries.M A PC-Based Development Programmer for the PIC16C84
AN589
After entering programming mode, RB7 is used to
Author: Robert Spur serially enter programming modes and data into the
Analog Design Specialist, Inc. part. A high to low transition on RB6, the clock input,
qualies each bit of the data applied on RB7. Please
INTRODUCTION refer to the PIC16C84 Programming Specication
(DS30189) for details on the gures. Th……
