Microchip Technology IC MCU OTP 2KX PIC17C42A-16/P DIP-40 MCP PIC17C42A-16/P Data Sheet
Product codes
PIC17C42A-16/P
PIC17C4X
DS30412C-page 108
1996 Microchip Technology Inc.
Table 15-2 lists the instructions recognized by the
MPASM assembler.
MPASM assembler.
All instruction examples use the following format to rep-
resent a hexadecimal number:
resent a hexadecimal number:
0xhh
where h signifies a hexadecimal digit.
To represent a binary number:
0000 0100b
where b signifies a binary string.
FIGURE 15-1: GENERAL FORMAT FOR
INSTRUCTIONS
Note 1:
Any unused opcode is Reserved. Use of
any reserved opcode may cause unex-
pected operation.
any reserved opcode may cause unex-
pected operation.
Note 2:
The shaded instructions are not available
in the PIC17C42
in the PIC17C42
Byte-oriented file register operations
15 9 8 7 0
d = 0 for destination WREG
OPCODE d f (FILE #)
d = 1 for destination f
f = 8-bit file register address
f = 8-bit file register address
Bit-oriented file register operations
15 11 10 8 7 0
OPCODE b (BIT #) f (FILE #)
b = 3-bit address
f = 8-bit file register address
f = 8-bit file register address
Literal and control operations
15 8 7 0
OPCODE k (literal)
k = 8-bit immediate value
Byte to Byte move operations
15 13 12 8 7 0
OPCODE p (FILE #) f (FILE #)
Call and GOTO operations
15 13 12 0
OPCODE k (literal)
k = 13-bit immediate value
p = peripheral register file address
f = 8-bit file register address
f = 8-bit file register address
15.1
Special Function Registers as
Source/Destination
Source/Destination
The PIC17C4X’s orthogonal instruction set allows read
and write of all file registers, including special function
registers. There are some special situations the user
should be aware of:
and write of all file registers, including special function
registers. There are some special situations the user
should be aware of:
15.1.1
ALUSTA AS DESTINATION
If an instruction writes to ALUSTA, the Z, C, DC and OV
bits may be set or cleared as a result of the instruction
and overwrite the original data bits written. For exam-
ple, executing
bits may be set or cleared as a result of the instruction
and overwrite the original data bits written. For exam-
ple, executing
CLRF ALUSTA
will clear register
ALUSTA, and then set the Z bit leaving
0000 0100b
in
the register.
15.1.2
PCL AS SOURCE OR DESTINATION
Read, write or read-modify-write on PCL may have the
following results:
following results:
Read PC:
PCH
→
PCLATH; PCL
→
dest
Write PCL:
PCLATH
→
PCH;
8-bit destination value
→
PCL
Read-Modify-Write:
PCL
→
ALU operand
PCLATH
→
PCH;
8-bit result
→
PCL
Where PCH = program counter high byte (not an
addressable register), PCLATH = Program counter
high holding latch, dest = destination, WREG or f.
addressable register), PCLATH = Program counter
high holding latch, dest = destination, WREG or f.
15.1.3
BIT MANIPULATION
All bit manipulation instructions are done by first read-
ing the entire register, operating on the selected bit and
writing the result back (read-modify-write). The user
should keep this in mind when operating on special
function registers, such as ports.
ing the entire register, operating on the selected bit and
writing the result back (read-modify-write). The user
should keep this in mind when operating on special
function registers, such as ports.