4502 Datasheet, PDF (88/116 Pages) Renesas Technology Corp – SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER

4502 Group
MACHINE INSTRUCTIONS (INDEX BY ALPHABET) (continued)
TYA (Transfer data to register Y from Accumulator)
Instruction
code
D9
D0
Number of Number of Flag CY
0000001100
00C
words
cycles
2
16
1
1
–
Skip condition
–
Operation: (Y) ← (A)
Grouping: Register to register transfer
Description: Transfers the contents of register A to regis-
ter Y.
WRST (Watchdog timer ReSeT)
Instruction
code
D9
D0
Number of Number of Flag CY
1010100000
2 A0
words
cycles
2
16
1
1
–
Skip condition
(WDF1) = 1
Operation:
(WDF1) = 1 ?
After skipping, (WDF1) ← 0
Grouping: Other operation
Description: Skips the next instruction when watchdog
timer flag WDF1 is “1.” After skipping, clears
(0) to the WDF1 flag. When the WDF1 flag
is “0,” executes the next instruction. Also,
stops the watchdog timer function when ex-
ecuting the WRST instruction immediately
after the DWDT instruction.
XAM j (eXchange Accumulator and Memory data)
Instruction D9
D0
Number of Number of Flag CY
code
101101j j j j
2 Dj
words
cycles
2
16
1
1
–
Skip condition
–
Operation:
(A) ←→ (M(DP))
(X) ← (X)EXOR(j)
j = 0 to 15
Grouping: RAM to register transfer
Description: After exchanging the contents of M(DP)
with the contents of register A, an exclusive
OR operation is performed between regis-
ter X and the value j in the immediate field,
and stores the result in register X.
XAMD j (eXchange Accumulator and Memory data and Decrement register Y and skip)
Instruction D9
D0
Number of Number of Flag CY
code
101111j j j j
2Fj
words
cycles
2
16
1
1
–
Skip condition
(Y) = 15
Operation:
(A) ←→ (M(DP))
(X) ← (X)EXOR(j)
j = 0 to 15
(Y) ← (Y) – 1
Grouping: RAM to register transfer
Description: After exchanging the contents of M(DP)
with the contents of register A, an exclusive
OR operation is performed between regis-
ter X and the value j in the immediate field,
and stores the result in register X.
Subtracts 1 from the contents of register Y.
As a result of subtraction, when the con-
tents of register Y is 15, the next instruction
is skipped. When the contents of register Y
is not 15, the next instruction is executed.
Rev.3.01 2005.02.02 page 88 of 112
REJ03B0105-0301