Rev.3.00
2004.08.06
page 17 of 155
REJ03B0010-0300Z
4584 Group
PRELIMINARY
Notice: This is not a final specification.
Some parametric limits are subject to change.
FUNCTION BLOCK OPERATIONS
CPU
(1) Arithmetic logic unit (ALU)
The arithmetic logic unit ALU performs 4-bit arithmetic such as 4-
bit data addition, comparison, AND operation, OR operation, and
bit manipulation.
(2) Register A and carry flag
Register A is a 4-bit register used for arithmetic, transfer, ex-
change, and I/O operation.
Carry flag CY is a 1-bit flag that is set to “1” when there is a carry
with the AMC instruction (Figure 1).
It is unchanged with both A n instruction and AM instruction. The
value of A0 is stored in carry flag CY with the RAR instruction (Fig-
ure 2).
Carry flag CY can be set to “1” with the SC instruction and cleared
to “0” with the RC instruction.
(3) Registers B and E
Register B is a 4-bit register used for temporary storage of 4-bit
data, and for 8-bit data transfer together with register A.
Register E is an 8-bit register. It can be used for 8-bit data transfer
with register B used as the high-order 4 bits and register A as the
low-order 4 bits (Figure 3).
Register E is undefined after system is released from reset and re-
turned from the RAM back-up. Accordingly, set the initial value.
(4) Register D
Register D is a 3-bit register.
It is used to store a 7-bit ROM address together with register A and
is used as a pointer within the specified page when the TABP p,
BLA p, or BMLA p instruction is executed. Also, when the TABP p
instruction is executed, the high-order 2 bits of the reference data
in ROM is stored to the low-order 2 bits of register D, and the con-
tents of the high-order 1 bit of register D is “0”. (Figure 4).
Register D is undefined after system is released from reset and re-
turned from the RAM back-up. Accordingly, set the initial value.
Fig. 1 AMC instruction execution example
Fig. 2 RAR instruction execution example
Fig. 3 Registers A, B and register E
Fig. 4 TABP p instruction execution example
(CY)
(M(DP))
(A)
Addition
ALU
<Carry>
<Result>
CY
A3 A2 A1 A0
A0
CY A3 A2 A1
<Rotation>
RAR instruction
<Set>
SC instruction
<Clear>
RC instruction
A3 A2 A1 A0
B3 B2 B1 B0
E7 E6 E5 E4 E3 E2 E1 E0
A3 A2 A1 A0
B3 B2 B1 B0
TAB instruction
TEAB instruction
TABE instruction
TBA instruction
Register BRegister A
Register B
Register A
Register E
Specifying address
TABP p instruction
p6 p5 p4 p3 p2 p1 p0
PCH
DR2 DR1DR0 A3 A2 A1 A0
PCL
Immediate field
value p
The contents of
register D
ROM
84
0
Middle-order 4 bits
Low-order 4bits
Register A (4)
Register B (4)
The contents of
register A
High-order 2 bits
Register D (3)
High-order 1 bit of
register D is “0”.