PIC18F66K22-I/PT Microchip Technology, PIC18F66K22-I/PT Datasheet - Page 133

• Manufacturer Part Number: PIC18F66K22-I/PT
• Description: 64kB Flash, 4kB RAM, 1kB EE, NanoWatt XLP, GP 64 TQFP 10x10x1mm TRAY
• Manufacturer: Microchip Technology
• Series: PIC® XLP™ 18Fr

Specifications of PIC18F66K22-I/PT

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 64MHz
• Connectivity: I²C, LIN, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LVD, POR, PWM, WDT
• Number Of I /o: 53
• Program Memory Size: 64KB (32K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 4K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 16x12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-TQFP
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

9.3
To read a data memory location, the user must write the
address to the EEADRH:EEADR register pair, clear the
EEPGD control bit (EECON1<7>) and then set control
bit, RD (EECON1<0>). The data is available in the
EEDATA register after one cycle; therefore, it can be
read after one NOP instruction. EEDATA will hold this
value until another read operation or until it is written to
by the user (during a write operation).
The basic process is shown in Example 9-1.
9.4
To write an EEPROM data location, the address must
first be written to the EEADRH:EEADR register pair
and the data written to the EEDATA register. The
sequence in Example 9-2 must be followed to initiate
the write cycle.
The write will not begin if this sequence is not exactly
followed (write 0x55 to EECON2, write 0xAA to
EECON2, then set WR bit) for each byte. It is strongly
recommended that interrupts be disabled during this
code segment.
Additionally, the WREN bit in EECON1 must be set to
enable writes. This mechanism prevents accidental
writes to data EEPROM due to unexpected code exe-
cution (i.e., runaway programs). The WREN bit should
be kept clear at all times, except when updating the
EEPROM. The WREN bit is not cleared by hardware.
 2010 Microchip Technology Inc.
Reading the Data EEPROM
Memory
Writing to the Data EEPROM
Memory
Preliminary
PIC18F87K22 FAMILY
After a write sequence has been initiated, EECON1,
EEADRH:EEADR and EEDATA cannot be modified.
The WR bit will be inhibited from being set unless the
WREN bit is set. The WREN bit must be set on a
previous instruction. Both WR and WREN cannot be
set with the same instruction.
At the completion of the write cycle, the WR bit is
cleared in hardware and the EEPROM Interrupt Flag bit
(EEIF) is set. The user may either enable this interrupt,
or poll this bit. EEIF must be cleared by software.
9.5
Depending on the application, good programming
practice may dictate that the value written to the
memory should be verified against the original value.
This should be used in applications where excessive
writes can stress bits near the specification limit.
Note:
Write Verify
Self-write
EEPROM memory cannot be done while
running in LP Oscillator mode (Low-Power
mode). Therefore, executing a self-write
will put the device into High-Power mode.
execution
DS39960B-page 133
to
Flash
and