TMP47C990E TOSHIBA [Toshiba Semiconductor], TMP47C990E Datasheet - Page 10

• Manufacturer Part Number: TMP47C990E
• Description: CMOS 4-bit Microcontroller
• Manufacturer: TOSHIBA [Toshiba Semiconductor]

TMP47C101/201
10/32
(5)
become unpredictable, so that they must be initialized by the
initialization routine.
When power-on is performed, the contents of the RAM
Example: To clear RAM (use common to the 47C101 and
SCLRRAM:
Zero-page
The 16 words (at addresses 00
zero page of the data memory can be used as the user
flags or pointers by using zero-page addressing mode
instructions (comparison, addition, transfer, and bit
manipulation), providing enhanced efficiency in pro-
gramming.
47C201)
LD
ST
B
ADD H, #1
B
HL, #00H
#0, @HL+
SCLRRAM
SCLRRAM
Figure 2-10. Data Memory Capacity and Address Assignment
H
through 0F
; HL 00H
; RAM [HL] 0, LR
; HR HR + 1
LR + 1
H
) of the
2.4.2 Data Memory Capacity
2.5 ALU and Accumulator
2.5.1 Arithmetic/Logic Unit (ALU)
The ALU performs the arithmetic and logic operations speci-
fied by instructions on 4-bit binary data and outputs the result
of the operation, the carry information(C), and the zero detect
information (z).
(1)
Example: To write immediate data “8” to address 09
SKIP:
Carry information (C)
The carry information indicates a carry-out from the
most significant bit in an addition. A subtraction is per-
formed as addition of two’s complement, so that, with
a subtraction, the carry information indicates that there
is no borrow to the most significant bit. With a rotate
instruction, the information indicates the data to be
shifted out from the accumulator.
TEST 04H,2
B
ST
bit 2 at address 04
#8, 09H ;
SKIP
;
Skips if bit 2 at address 04
Writes “8” to address 09
the RAM is “0”.
RAM
TOSHIBA CORPORATION
H
in the RAM is “1”.
H
in the
H
in
H
if