HTG12G0 Datasheet, PDF (27/31 Pages) Holtek Semiconductor Inc – Microcontroller

READF MR0A
Machine code
Description
Operation
READF R4A
Machine code
Description
Operation
RET
Machine code
Description
Operation
RETI
Machine code
Description
Operation
RL A
Machine code
Description
Operation
HTG12G0
Read ROM Code of page F to M(R1,R0) and ACC
01001111
The 8-bit ROM code (page F) addressed by ACC and R4 is moved to the data
memory M(R1,R0) and the accumulator. The high nibble of the ROM code is
loaded to M(R1,R0) and the low nibble of the ROM code is loaded to the
accumulator.
Page F → ROM code address bit 11~8 are “1111”
ACC → ROM code address bit 7~4
R4 → ROM code address bit 3~0
M(R1,R0) ← high nibble of ROM code (page F)
ACC ← low nibble of ROM code (page F)
Read ROM code of page F to R4 and accumulator
01001101
The 8-bit ROM code (page F) addressed by ACC and M(R1,R0) is moved to
the working register R4 and the accumulator. The high nibble of the ROM
code is loaded to R4 and the low nibble of the ROM code is loaded to the
accumulator.
Page F → ROM code address bit 11~8 are “1111”
ACC → ROM code address bit 7~4
M(R1,R0) → ROM code address bit 3~0
R4 ← high nibble of ROM code (page F)
ACC ← low nibble of ROM code (page F)
Return from subroutine or interrupt
00101110
The program counter bits 0~11 are restored from the stack.
PC ← Stack
Return from interrupt subroutine
00101111
The program counter bits 0~11 are restored from the stack. The carry flag is
restored before entering the interrupt service routine.
PC ← Stack
CF ← CF (before interrupt service routine)
Rotate accumulator left
00000001
The contents of the accumulator are rotated left by 1 bit. Bit 3 is rotated to
both bit 0 and the carry flag.
An+1 ← An, An: accumulator bit n (n=0,1,2)
A0 ← A3
CF ← A3
27
14th May ’99