PD64A_15 Datasheet, PDF (23/66 Pages) Renesas Technology Corp – 4-BIT SINGLE-CHIP MICROCONTROLLERS FOR INFRARED REMOTE CONTROL TRANSMISSION

µPD64A, 65
4.3 Carrier Output
The carrier for remote-controlled transmission can be output from the REM pin by clearing (0) bit 2 of control
register 0.
As shown in Figure 4-3, in the case where the timer stops when the carrier is at a high level, the carrier continues
to be output until its next fall and then stops due to the function of the carrier synchronous circuit. When the timer
starts operation, however, the high-level width of the first carrier may become shorter than the specified width.
Figure 4-3. Timer Output (When Carrier Is Output)
Timer value: (Set value + 1) × 64/fX (or 128/fX)
LED
REM (low-level start)
REM (high-level start)
Note 2
Note 1
Notes 1. Error when the REM output ends: Lead by “carrier low-level width” to lag by “carrier high-
level width”
2. Error of carrier high-level width: 0 to “carrier high-level width”
4.4 Software Control of Timer Output
The timer output can be controlled by software. As shown in Figure 4-4, a pulse with a minimum width of 1
instruction cycle (64/fX) can be output.
Figure 4-4. Pulse Output of 1 Instruction Cycle Width
MOV T, #0000000000B; low-level output from the REM pin
MOV T, #1000000000B; high-level output from the REM pin
MOV T, #0000000000B; low-level output from the REM pin
64/fX
LED
REM
Data Sheet U14380EJ3V0DS00
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