EM73962A
4-BIT MICROCONTROLLER
(3) Rotation:
There are two kinds of rotation operation, one is rotation left, the other is rotation right.
RLCA instruction rotates Acc value to left, shift the CF value into the LSB bit of Acc and the shift out data
will be hold in CF.
MSB LSB
ACC
CF
RRCA instruction operation rotates Acc value to right, shift the CF value into the MSB bit of Acc and the
shift out data will be hold in CF.
MSB LSB
ACC
CF
PROGRAM EXAMPLE: To rotate Acc right and shift a "1" into the MSB bit of Acc.
TTCFS; CF ← 1
RRCA; rotate Acc right and shift CF=1 into MSB.
HL REGISTER
HL register are two 4-bit registers, they are used as a pair of pointer for the address of RAM memory and also
2 independent temporary 4-bit data registers. For some instruction, L register can be a pointer to indicate the
pin number ( Port4 ).
HL REGISTER STRUCTURE
3 2 1 0 3 2 1 0
L REGISTER
H REGISTER
HL REGISTER FUNCTION
(1)For instruction : LDL #k, LDH #k, THA, THL, INCL, DECL, EXAL, EXAH, HL register used as a
temporary register.
PROGRAM EXAMPLE: Load immediate data "5h" into L register, "Dh" into H register.
LDL#05h;
LDH#0Dh;
(2) For instruction LDAM, STAM, STAMI .., HL register used as a pointer for the address of RAM memory.
PROGRAM EXAMPLE: Store immediate data #Ah into RAM of address 35h.
* This specification are subject to be changed without notice.
10.8.2001
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ELAN [ ELAN MICROELECTRONICS CORP ]
