PIC16F737-I Datasheet, PDF (34/276 Pages) Microchip Technology – 28/40/44-Pin, 8-Bit CMOS Flash Microcontrollers with 10-Bit A/D and nanoWatt Technology

PIC16F7X7
3.3 Reading the Flash Program
Memory
A program memory location may be read by writing two
bytes of the address to the PMADR and PMADRH reg-
isters and then setting control bit, RD (PMCON1<0>).
Once the read control bit is set, the microcontroller will
use the next two instruction cycles to read the data. The
data is available in the PMDATA and PMDATH
registers after the second NOP instruction; therefore, it
can be read as two bytes in the following instructions.
The PMDATA and PMDATH registers will hold this
value until the next read operation.
3.4 Operation During Code-Protect
Flash program memory has its own code-protect
mechanism. External read and write operations by
programmers are disabled if this mechanism is
enabled.
The microcontroller can read and execute instructions
out of the internal Flash program memory, regardless
of the state of the code-protect configuration bits.
EXAMPLE 3-1: FLASH PROGRAM READ
BSF
BCF
MOVF
MOVWF
MOVF
MOVWF
BSF
STATUS, RP1
STATUS, RP0
ADDRH, W
PMADRH
ADDRL, W
PMADR
STATUS, RP0
;
; Bank 2
;
; MSByte of Program Address to read
;
; LSByte of Program Address to read
; Bank 3 Required
Required BSF
Sequence NOP
NOP
PMCON1, RD
; EEPROM Read Sequence
; memory is read in the next two cycles after BSF PMCON1,RD
;
BCF
MOVF
MOVF
STATUS, RP0
PMDATA, W
PMDATH, W
; Bank 2
; W = LSByte of Program PMDATA
; W = MSByte of Program PMDATH
TABLE 3-1: REGISTERS ASSOCIATED WITH PROGRAM FLASH
Address Name
Bit 7
Bit 6 Bit 5 Bit 4 Bit 3
Bit 2
Bit 1
Bit 0
Value on:
POR, BOR
Value on
all other
Resets
10Dh PMADR EEPROM Address Register Low Byte
xxxx xxxx uuuu uuuu
10Fh PMADRH —
— — — EEPROM Address Register High Byte ---- xxxx ---u uuuu
10Ch PMDATA EEPROM Data Register Low Byte
xxxx xxxx uuuu uuuu
10Eh
18Ch
PMDATH —
— EEPROM Data Register High Byte
PMCON1 reserved⁽¹⁾ —
—
—
—
—
—
--xx xxxx --uu uuuu
RD 1--- ---0 1--- ---0
Legend: x = unknown, u = unchanged, — = unimplemented, read as ‘0’. Shaded cells are not used during Flash access.
Note 1: This bit always reads as a ‘1’.
DS30498C-page 32
 2004 Microchip Technology Inc.