UPD6132 Datasheet, PDF (21/64 Pages) NEC – 4-BIT SINGLE-CHIP MICROCONTROLLER FOR INFRARED REMOTE CONTROL TRANSMISSION

µPD6132
4.3 Carrier Output
The carrier for remote-controlled transmission can be output from the REM pin by clearing (to 0) bit 2 of the 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) × 8/fX (or 16/fX)
LED
REM (at low-level start)
REM (at high-level start)
Note 1
Note 2
Notes 1. Error when the REM output ends: Lead by “the carrier’s low-level width” to lag by “the carrier’s high-
level width”
2. Error of the carrier’s high-level width: 0 to “the carrier’s high-level width”
4.4 Software Control of Timer Output
The timer output can be controlled by software. As shown in Figure 4-4, the pulse with a minimum width of 1-
instruction cycle (8/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
8/fX
LED
REM
Data Sheet U14332EJ1V0DS00
21