upd64a Renesas Electronics Corporation., upd64a Datasheet - Page 26

• Manufacturer Part Number: upd64a
• Description: 4-bit Single-chip Microcontroller For Infrared Remote Control Transmission
• Manufacturer: Renesas Electronics Corporation.

6. RESET
26
PC (11 bits)
SP (1 bit)
Data
memory
Accumulator (A)
Status flag (F)
Carry flag (CY)
Timer (10 bits)
Port register
Control register P3
The system is reset by the following occurrences.
• When the POC circuit has detected low-power voltage
• When the operand value is illegal or does not satisfy the precondition when the HALT instruction is executed
• When the accumulator is 0H when the RLZ instruction is executed
• When the stack pointer overflows or underflows
Notes 1. The following resets are available.
Hardware
2. Value according to the K
R0 = DP
R1 to RF
• Reset when executing the HALT instruction (when the operand value is illegal or does not satisfy
• Reset when executing the RLZ instruction (when A = 0)
• Reset by stack pointer overflow or underflow
In order to prevent malfunction, do not input a high level to all the K
due to supply voltage startup (these pins can be left open. When leaving open, keep pull-down
resistors connected).
the precondition)
P0
P1
P4
• Reset by Internal POC Circuit in Operation
• Reset by Other Factor
000H
0B
000H
Undefined
Undefined
0B
0B
000H
FFH
03H
26H
11 1B
Note 2
Table 6-1. Hardware Statuses After Reset
I
or S
Note 1
2
Data Sheet U14380EJ3V0DS00
pin status.
• Reset by Internal POC Circuit in
Previous status retained
Standby Mode
I0
to K
I3
pins when POC is released
PD64A, 65