PIC18F26K80-E/SP Microchip Technology Inc., PIC18F26K80-E/SP Datasheet - Page 129

• Manufacturer Part Number: PIC18F26K80-E/SP
• Description: 28 SPDIP .300IN TUBE, ECAN, 64KB FLASH, 4KB RAM, 16 MIPS, 12-BIT ADC, CTMU
• Manufacturer: Microchip Technology Inc.

Specifications of PIC18F26K80-E/SP

• A/d Inputs: 8-Channel, 12-Bit
• Comparators: 2
• Cpu Speed: 16 MIPS
• Eeprom Memory: 256 Bytes
• Input Output: 24
• Interface: I2C/SPI/UART/USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 28-pin SPDIP
• Programmable Memory: 64K Bytes
• Ram Size: 3.6K Bytes
• Speed: 64 MHz
• Temperature Range: –40 to 125 °C
• Timers: 2-8-bit, 3-16-bit
• Voltage, Range: 1.8-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part

6.4.3.1
At the core of Indirect Addressing are three sets of
registers: FSR0, FSR1 and FSR2. Each represents a
pair of 8-bit registers: FSRnH and FSRnL. The four
upper bits of the FSRnH register are not used, so each
FSR pair holds a 12-bit value. This represents a value
that can address the entire range of the data memory
in a linear fashion. The FSR register pairs, then, serve
as pointers to data memory locations.
Indirect Addressing is accomplished with a set of Indi-
rect File Operands, INDF0 through INDF2. These can
be thought of as “virtual” registers. The operands are
FIGURE 6-8:
 2011 Microchip Technology Inc.
Using an instruction with one of the
Indirect Addressing registers as the
operand....
...uses the 12-bit address stored in
the FSR pair associated with that
register....
...to determine the data memory
location to be used in that operation.
In this case, the FSR1 pair contains
FCCh. This means the contents of
location FCCh will be added to that
of the W register and stored back in
FCCh.
FSR Registers and the
INDF Operand
INDIRECT ADDRESSING
x x x x 1 1 1 1
7
ADDWF, INDF1, 1
Preliminary
FSR1H:FSR1L
0
7
1 1 0 0 1 1 0 0
PIC18F66K80 FAMILY
mapped in the SFR space, but are not physically imple-
mented. Reading or writing to a particular INDF register
actually accesses its corresponding FSR register pair.
A read from INDF1, for example, reads the data at the
address indicated by FSR1H:FSR1L.
Instructions that use the INDF registers as operands
actually use the contents of their corresponding FSR as
a pointer to the instruction’s target. The INDF operand
is just a convenient way of using the pointer.
Because Indirect Addressing uses a full 12-bit address,
data RAM banking is not necessary. Thus, the current
contents of the BSR and the Access RAM bit have no
effect on determining the target address.
0
FFFh
E00h
F00h
000h
100h
200h
300h
Data Memory
DS39977C-page 129
Bank 13
Bank 14
Bank 15
through
Bank 0
Bank 1
Bank 2
Bank 3