EM73P968 datasheet(16/53 Pages) EMC

16 / 53 page

* This specification are subject to be changed without notice.

8.14.2001

EM73P968

4-BIT MICRO-CONTROLLER FOR LCD PRODUCT

Preliminar

EXAMPLE:

Operation

Carry Zero

8-4=4

7-F= -8(1000)

9-9=0

ACC

MSB

LSB

H REGISTER

L REGISTER

ACC

MSB

LSB

(3) Rotation:

Two types of rotation operation are available, one is rotation left, the other is rotation right.

RLCA instruction rotates Acc value counter-clockwise, shift the CF value into the LSB bit of Acc and hold

the shift out data in CF.

RRCA instruction operation rotates Acc value clockwise, shift the CF value into the MSB bit of Acc and

hold the shift out data in CF.

PROGRAM EXAMPLE: To rotate Acc clockwise (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 RAM memoryaddress. They are

used as also 2 independent temporary 4-bit data registers. For certain instructions, L register can be a pointer

to indicate the pin number (Port4 only).

HL REGISTER STRUCTURE

HL REGISTER FUNCTION

(1) HL register is used as a temporary register for instructions : LDL #k, LDH #k, THA, THL, INCL, DECL,

EXAL, EXAH.

PROGRAM EXAMPLE: Load immediate data "5h" into L register, "0Dh" into H register.

LDL #05h;

LDH #0Dh;

(2) HL register is used as a pointer for the address of RAM memory for instructions : LDAM, STAM, STAMI ..

PROGRAM EXAMPLE: Store immediate data "#0Ah" into RAM of address 35h.

EM73P968 Datasheet(PDF) 16 Page - ELAN Microelectronics Corp