PIC12CE67 Microchip Technology, PIC12CE67 Datasheet - Page 62

• Manufacturer Part Number: PIC12CE67
• Description: 8-Pin/ 8-Bit CMOS Microcontroller with A/D Converter and EEPROM Data Memory
• Manufacturer: Microchip Technology

PIC12CE67X
10.1
The PIC12CE67X’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:
10.1.1
If an instruction writes to STATUS, the Z, C and DC bits
may be set or cleared as a result of the instruction and
overwrite the original data bits written. For example,
executing CLRF STATUS will clear register STATUS, and
then set the Z bit leaving 0000 0100b in the register.
10.1.2
Bit 3 of the TRIS register always reads as a '1' since
GP3 is an input only pin. This fact can affect some read-
modify-write operations on the TRIS register.
DS40181B-page 62
Special Function Registers as
Source/Destination
STATUS AS DESTINATION
TRIS AS DESTINATION
Preliminary
10.1.3
Read, write or read-modify-write on PCL may have the
following results:
Read PC:
Write PCL:
Read-Modify-Write:
Where PCH = program counter high byte (not an
addressable register), PCLATH = Program counter
high holding latch, dest = destination, WREG or f.
10.1.4
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.
PCL AS SOURCE OR DESTINATION
BIT MANIPULATION
PCL
PCLATH
8-bit destination value
PCL
PCLATH
8-bit result
1998 Microchip Technology Inc.
ALU operand
dest
PCH;
PCH;
PCL
PCL