PIC18F458T-I/PT Microchip Technology, PIC18F458T-I/PT Datasheet - Page 70

• Manufacturer Part Number: PIC18F458T-I/PT
• Description: IC MCU FLASH 16KX16 W/CAN 44TQFP
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F458T-I/PT

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: CAN, I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LVD, POR, PWM, WDT
• Number Of I /o: 33
• Program Memory Size: 32KB (16K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 1.5K x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-TQFP, 44-VQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

6.2.2
The Table Latch (TABLAT) is an 8-bit register mapped
into the SFR space. The Table Latch is used to hold
8-bit data during data transfers between program
memory and data RAM.
6.2.3
The Table Pointer (TBLPTR) addresses a byte within
the program memory. The TBLPTR is comprised of
three SFR registers: Table Pointer Upper Byte, Table
Pointer High Byte and Table Pointer Low Byte
(TBLPTRU:TBLPTRH:TBLPTRL). These three regis-
ters join to form a 22-bit wide pointer. The low-order
21 bits allow the device to address up to 2 Mbytes of
program memory space. The 22nd bit allows access to
the device ID, the user ID and the configuration bits.
The Table Pointer, TBLPTR, is used by the TBLRD and
TBLWT instructions. These instructions can update the
TBLPTR in one of four ways based on the table
operation. These operations are shown in Table 6-1.
These operations on the TBLPTR only affect the
low-order 21 bits.
TABLE 6-1:
FIGURE 6-3:
DS41159E-page 68
PIC18FXX8
TBLRD*+
TBLWT*+
TBLRD*-
TBLWT*-
TBLRD+*
TBLWT+*
Example
TBLRD*
TBLWT*
21
TABLAT – TABLE LATCH REGISTER
TBLPTR – TABLE POINTER
REGISTER
TABLE POINTER OPERATIONS WITH TBLRD AND TBLWT INSTRUCTIONS
TBLPTRU
TABLE POINTER BOUNDARIES BASED ON OPERATION
16
ERASE – TBLPTR<21:6>
15
TBLPTR is incremented before the read/write
TBLPTR is decremented after the read/write
TBLPTR is incremented after the read/write
WRITE – TBLPTR<21:3>
TBLPTRH
READ – TBLPTR<21:0>
Operation on Table Pointer
TBLPTR is not modified
memory block of 8 bytes is written to. For more detail,
6.2.4
TBLPTR is used in reads, writes and erases of the
Flash program memory.
When a TBLRD is executed, all 22 bits of the Table
Pointer determine which byte is read from program
memory into TABLAT.
When a TBLWT is executed, the three LSbs of the Table
Pointer (TBLPTR<2:0>) determine which of the eight
program memory holding registers is written to. When
the timed write to program memory (long write) begins,
the
(TBLPTR<21:3>),
see Section 6.5 “Writing to Flash Program Memory”.
When an erase of program memory is executed, the
16 MSbs of the Table Pointer (TBLPTR<21:6>) point to
the 64-byte block that will be erased. The Least
Significant bits (TBLPTR<5:0>) are ignored.
Figure 6-3 describes the relevant boundaries of
TBLPTR based on Flash program memory operations.
19
8
MSbs
7
TABLE POINTER BOUNDARIES
of
will
TBLPTRL
the
© 2006 Microchip Technology Inc.
determine
Table
Pointer,
which
0
TBLPTR
program