UPD17217GT datasheet(29/84 Pages) NEC

29 / 84 page

µPD17215, 17216, 17217, 17218

8-BIT TIMER AND REMOTE CONTROLLER CARRIER GENERATOR CIRCUIT

The

µPD17215 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

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.

76543210

TMC

TMM

Address

On reset

R/W

Peripheral register: 05H

00H

Address

On reset

R/W

Peripheral register: 06H

FFH

8-bit counter

76543210

8-bit modulo register

Caution:

Do note clear TMM to 0 (IRQTM is not set).

UPD17217GT Datasheet(PDF) 29 Page - NEC