PD62A_15 Datasheet, PDF (14/64 Pages) Renesas Technology Corp – 4-BIT SINGLE-CHIP MICROCONTROLLER FOR INFRARED REMOTE CONTROL TRANSMISSION

µPD62A
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 (to 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 canceled.
• When the cancelation condition is met at the point of executing the HALT instruction. (In this case, the system
is not placed in standby mode.)
Conversely, the status flag is cleared (to 0) in the following cases:
• If the condition specified with the operand is not met when the STTS instruction has been executed.
• When the status flag has been set (to 1), the HALT instruction executed, but the cancelation condition is not
met at the point of executing the HALT instruction. (In this case, the system is not placed in 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 input to at least one of KI pins.
High level input to at least one of KI pins.
High level input to at least one of KI pins.
The down counter of the timer is 0.
[The following condition is added in addition to the above.]
High level input to at least one of S0 and S1 pins^Note.
Note The S0 and S1 pins must be set in input mode (set bit 2 and bit 0 of the P4 resister to 0 and 1 respectively).
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Data Sheet U14474EJ2V0DS00