PD17225_15 Datasheet, PDF (32/86 Pages) Renesas Technology Corp – 4-BIT SINGLE-CHIP MICROCONTROLLER FOR SMALL GENERAL-PURPOSE INFRARED REMOTE CONTROL TRANSMITTER

µPD17225, 17226, 17227, 17228
5. 8-BIT TIMER AND REMOTE CONTROLLER CARRIER GENERATOR CIRCUIT
The µPD17225 is equipped with the 8-bit timer which is mainly used to generate the leader pulse of the remote controller
signal, and to output codes.
5.1 Configuration of 8-bit Timer (with modulo function)
Figure 5-1 shows the configuration of the 8-bit timer.
As shown in this figure, the 8-bit timer consists of an 8-bit counter (TMC), an 8-bit modulo register (TMM), a comparator
that compares the value of the timer with the value of the modulo register, and a selector that selects the operation clock
of the 8-bit timer.
To start/stop the 8-bit timer, and to reset the 8-bit counter, TMEN (address 33H, bit 3) and TMRES (address 33H, bit
2) of the register file are used. To select the operation clock of the 8-bit timer, use TMCK1 (address 33H, bit 1) and TMCK0
(address 33H, bit 0) of the register file.
The value of the 8-bit counter is read by using the GET instruction through DBF (data buffer). No value can be set to
the 8-bit counter. A value is set to the modulo register by using the PUT instruction through DBF. The value of the modulo
register cannot be read.
When the value of the counter coincides with that of the modulo register, an interrupt flag (IRQTM: address 3FH, bit
0) of the register file is set.
TMC
76543210
Address
On reset
R/W
8-bit counter
Peripheral register: 05H
00H
R
TMM
76543210
Address
On reset
R/W
8-bit modulo register
Peripheral register: 06H
FFH
W
Caution Do not clear TMM to 0 (IRQTM is not set).
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Data Sheet U12643EJ2V0DS00