Many applications require the microcontroller to cal-
culate a checksum on the program memory to deter-
mine if the contents have been corrupted. Until now,
the only family of PICmicro
®
microcontrollers to have
the capability to read from program memory are the
PIC17CXXX devices. The PIC16F87X devices are
the first 14-bit core PICmicro microcontrollers that
are able to access program memory in the same
fashion as used with data EEPROM memory. These
devices are FLASH extensions of the popular
PIC16C7X family. Table 1 shows a comparison
between the two PICmicro microcontroller families.M Calculating Program Memory Checksums Using a PIC16F87X
TB026
ACCESSING MEMORY
Author: Rodger Richey
Microchip Technology Inc. The data EEPROM and FLASH Program memory are
both accessed using the same method. An address
and/or data value are stored in Special Function Reg-
isters (SFR) and then memory is accessed using con-
INTRODUCTION trol bits in other SFRs. There are six SFRs required to
Many ……
