PIC16C926-I/CL Microchip Technology, PIC16C926-I/CL Datasheet - Page 29

• Manufacturer Part Number: PIC16C926-I/CL
• Description: 64/68-Pin CMOS Microcontrollers with LCD Driver
• Manufacturer: Microchip Technology

3.0
The Program Memory is readable during normal oper-
ation over the entire V
addressed through Special Function Registers (SFR).
Up to 14-bit numbers can be stored in memory for use
as calibration parameters, serial numbers, packed 7-bit
ASCII, etc. Executing a program memory location con-
taining data that forms an invalid instruction results in a
NOP.
There are five SFRs used to read the program and
memory. These registers are:
• PMCON1
• PMDATA
• PMDATH
• PMADR
• PMADRH
The program memory allows word reads. Program
memory access allows for checksum calculation and
reading calibration tables.
REGISTER 3-1: PMCON1 REGISTER (ADDRESS 10Ch)
2001 Microchip Technology Inc.
bit 7
bit 6-1
bit 0
READING PROGRAM MEMORY
bit 7
Reserved: Read as ‘1’
Unimplemented: Read as ‘0’
RD: Read Control bit
1 = Initiates a read, RD is cleared in hardware. The RD bit can only be set (not cleared)
0 = Does not initiate a read
Legend:
R = Readable bit
- n = Value at POR reset
R-1
in software.
r
DD
range. It is indirectly
U-0
—
U-0
—
Preliminary
W = Writable bit
’1’ = Bit is set
U-0
—
When interfacing to the program memory block, the
PMDATH:PMDATA registers form a two-byte word,
which
PMADRH:PMADR registers form a two-byte word,
which holds the 13-bit address of the location being
accessed. These devices can have from 4K words to
8K words of program memory, with an address range
from 0h to 3FFFh.
The unused upper bits in both the PMDATH and
PMADRH registers are not implemented and read as
“0’s”.
3.1
The address registers can address up to a maximum of
8K words of program memory.
When selecting a program address value, the MSByte
of the address is written to the PMADRH register and
the LSByte is written to the PMADR register. The upper
MSbits of PMADRH must always be clear.
3.2
PMCON1 is the control register for memory accesses.
The control bit RD initiates read operations. This bit
cannot be cleared, only set, in software. It is cleared in
hardware at the completion of the read operation.
holds
PMADR
PMCON1 Register
U = Unimplemented bit, read as ‘0’
’0’ = Bit is cleared
U-x
—
PIC16C925/926
the
14-bit
U-0
—
data
x = Bit is unknown
U-0
—
DS39544A-page 27
for
reads.
R/S-0
RD
bit 0
The