PIC18F-LF1XK50 MICROCHIP [Microchip Technology], PIC18F-LF1XK50 Datasheet - Page 52

• Manufacturer Part Number: PIC18F-LF1XK50
• Description: 20-Pin USB Flash Microcontrollers
• Manufacturer: MICROCHIP [Microchip Technology]

PIC18F1XK50/PIC18LF1XK50
FIGURE 4-2:
4.2
Several control registers are used in conjunction with
the TBLRD and TBLWT instructions. These include the:
• EECON1 register
• EECON2 register
• TABLAT register
• TBLPTR registers
4.2.1
The EECON1 register
register for memory accesses. The EECON2 register is
not a physical register; it is used exclusively in the
memory
EECON2 will read all ‘0’s.
The EEPGD control bit determines if the access will be
a program or data EEPROM memory access. When
EEPGD is clear, any subsequent operations will
operate on the data EEPROM memory. When EEPGD
is set, any subsequent operations will operate on the
program memory.
The CFGS control bit determines if the access will be
to the Configuration/Calibration registers or to program
memory/data EEPROM memory. When CFGS is set,
subsequent operations will operate on Configuration
registers regardless of EEPGD (see
“Special Features of the
memory selection access is determined by EEPGD.
DS41350E-page 52
Note 1: During table writes the Table Pointer does not point directly to Program Memory. The LSBs of TBLPRTL
Control Registers
TBLPTRU
write
EECON1 AND EECON2 REGISTERS
(TBLPTR<MSBs>)
Program Memory
actually point to an address within the write block holding registers. The MSBs of the Table Pointer deter-
mine where the write block will eventually be written. The process for writing the holding registers to the
program memory array is discussed in
and
Table Pointer
TBLPTRH
TABLE WRITE OPERATION
erase
(Register
CPU”). When CFGS is clear,
(1)
sequences.
TBLPTRL
4-1) is the control
Section 24.0
Reading
Preliminary
Section 4.5 “Writing to Flash Program
Instruction: TBLWT*
Program Memory
The FREE bit allows the program memory erase oper-
ation. When FREE is set, an erase operation is initiated
on the next WR command. When FREE is clear, only
writes are enabled.
The WREN bit, when set, will allow a write operation.
The WREN bit is clear on power-up.
The WRERR bit is set by hardware when the WR bit is
set and cleared when the internal programming timer
expires and the write operation is complete.
The WR control bit initiates write operations. The WR
bit cannot be cleared, only set, by firmware. Then WR
bit is cleared by hardware at the completion of the write
operation.
Note:
Note:
During normal operation, the WRERR is
read as ‘1’. This can indicate that a write
operation was prematurely terminated by
a Reset, or a write operation was
attempted improperly.
The EEIF interrupt flag bit of the PIR2
register is set when the write is complete.
The EEIF flag stays set until cleared by
firmware.
Holding Registers
 2010 Microchip Technology Inc.
Memory”.
Table Latch (8-bit)
TABLAT