PIC18F86K90-I/PT Microchip Technology, PIC18F86K90-I/PT Datasheet - Page 89

• Manufacturer Part Number: PIC18F86K90-I/PT
• Description: 64kB Flash, 4kB RAM, 1kB EE, 16MIPS, NanoWatt XLP, LCD, 5V 80 TQFP 12x12x1mm TRA
• Manufacturer: Microchip Technology
• Series: PIC® XLP™ 18Fr

Specifications of PIC18F86K90-I/PT

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 64MHz
• Connectivity: I²C, LIN, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LCD, POR, PWM, WDT
• Number Of I /o: 69
• 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 24x12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 80-TQFP
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

6.2.3
The program memory is addressed in bytes. Instructions
are stored as two or four bytes in program memory. The
Least Significant Byte of an instruction word is always
stored in a program memory location with an even
address (LSB = 0). To maintain alignment with
instruction boundaries, the PC increments in steps of
two and the LSB will always read ‘0’ (see Section 6.1.2
“Program Counter”).
Figure 6-5 shows an example of how instruction words
are stored in the program memory.
FIGURE 6-5:
6.2.4
The standard PIC18 instruction set has four two-word
instructions: CALL, MOVFF, GOTO and LSFR. In all
cases, the second word of the instructions always has
‘1111’ as its four Most Significant bits. The other 12 bits
are literal data, usually a data memory address.
The use of ‘1111’ in the 4 MSbs of an instruction
specifies a special form of NOP. If the instruction is
executed in proper sequence, immediately after the
first word, the data in the second word is accessed and
EXAMPLE 6-4:
 2010 Microchip Technology Inc.
CASE 1:
Object Code
CASE 2:
Object Code
0110 0110 0000 0000
1100 0001 0010 0011
1111 0100 0101 0110
0010 0100 0000 0000
0110 0110 0000 0000
1100 0001 0010 0011
1111 0100 0101 0110
0010 0100 0000 0000
INSTRUCTIONS IN PROGRAM
MEMORY
TWO-WORD INSTRUCTIONS
Instruction 1:
Instruction 2:
Instruction 3:
INSTRUCTIONS IN PROGRAM MEMORY
TWO-WORD INSTRUCTIONS
Program Memory
Byte Locations
MOVLW
GOTO
MOVFF
Source Code
TSTFSZ
Source Code
MOVFF
ADDWF
TSTFSZ
MOVFF
ADDWF
055h
0006h
123h, 456h

REG1
REG1, REG2 ; No, skip this word
REG3
REG1
REG1, REG2 ; Yes, execute this word
REG3

Preliminary
LSB = 1
; is RAM location 0?
; Execute this word as a NOP
; continue code
; is RAM location 0?
; 2nd word of instruction
; continue code
PIC18F87K90 FAMILY
EFh
C1h
0Fh
F0h
F4h
The CALL and GOTO instructions have the absolute
program memory address embedded into the instruc-
tion. Since instructions are always stored on word
boundaries, the data contained in the instruction is a
word address. The word address is written to PC<20:1>
which accesses the desired byte address in program
memory. Instruction #2 in Figure 6-5 shows how the
instruction, GOTO 0006h, is encoded in the program
memory. Program branch instructions, which encode a
relative address offset, operate in the same manner. The
offset value stored in a branch instruction represents the
number of single-word instructions that the PC will be
offset by. For more details on the instruction set, see
Section 29.0 “Instruction Set Summary”.
used by the instruction sequence. If the first word is
skipped for some reason, and the second word is
executed by itself, a NOP is executed instead. This is
necessary for cases when the two-word instruction is
preceded by a conditional instruction that changes the
PC. Example 6-4 shows how this works.
Note:
LSB = 0
55h
03h
00h
23h
56h
For information on two-word instructions in
the
Section 6.5 “Program Memory and the
Extended Instruction Set”.
extended
Word Address
00000Ah
00000Ch
00000Eh
000000h
000002h
000004h
000006h
000008h
000010h
000012h
000014h

instruction
DS39957B-page 89
set,
see