PD64A_15 Datasheet, PDF (14/66 Pages) Renesas Technology Corp – 4-BIT SINGLE-CHIP MICROCONTROLLERS FOR INFRARED REMOTE CONTROL TRANSMISSION

µPD64A, 65
2.8 Arithmetic and Logic Unit (ALU): 4 Bits
The arithmetic and logic unit (ALU), which is an arithmetic circuit consisting of 4 bits, executes simple
manipulations with priority given to logical operations.
2.9 Flags
2.9.1 Status flag (F)
Pin and timer statuses can be checked by executing the STTS instruction to check the status flag.
The status flag is set (1) in the following cases.
• If the condition specified with the operand is met when the STTS instruction has been executed.
• When standby mode is released.
• When the release condition is met at the point of executing the HALT instruction. (In this case, the system
does not enter standby mode.)
Conversely, the status flag is cleared (0) in the following cases.
• If the condition specified with the operand is not met when the STTS instruction has been executed.
• While the status flag is set (1), the HALT instruction is executed, but the release condition is not met at the
point of executing the HALT instruction. (In this case, the system does not enter standby mode.)
Table 2-1. Conditions for Status Flag (F) to Be Set by STTS Instruction
Operand Value of STTS Instruction
b3
b2
b1
b0
0
0
0
0
0
1
1
1
1
0
1
0
1
1
Any combination
of b2, b1, and b0 above
Condition for Status Flag (F) to Be Set
High level is input to at least one of the KI pins.
High level is input to at least one of the KI pins.
High level is input to at least one of the KI pins.
The down counter of the timer is 0.
[The following condition is added in addition to the above.]
High level is input to at least one of the S0^{Note 1}, S1^{Note 1}, and S2^{Note 2} pins.
Notes 1. The S0 and S1 pins must be set to input mode (bit 2 of the P4 register is set to 0 and bit 0 to 1).
2. The use of STOP mode release for the S2 pin must be enabled (bit 3 of the P4 register is set to 1).
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Data Sheet U14380EJ3V0DS00