HD404324FS datasheet(51/103 Pages) RENESAS

51 / 103 page

HD404054 Series/HD404094 Series

Timer C Operations:

• Free-running/reload timer operation: The free-running/reload operation, input clock source, and

prescaler division ratio are selected by timer mode register C1 (TMC1: $00D).

Timer C is initialized to the value set in timer write register C (TWCL: $00E, TWCU: $00F) by

software and incremented by one at each clock input. If an input clock is applied to timer C after it has

reached $FF, an overflow is generated. In this case, if the reload timer function is enabled, timer C is

initialized to its initial value set in timer write register C; if the free-running timer function is enabled,

the timer is initialized to $00 and then incremented again.

The overflow sets the timer C interrupt request flag (IFTC: $002, bit 2). IFTC is reset by software or

MCU reset. Refer to figure 3 and table 1 for details.

• Watchdog timer operation: Timer C is used as a watchdog timer for detecting out-of-control program

routines by setting the watchdog on flag (WDON: $020, bit 1) to 1. If a program routine runs out of

control and an overflow is generated, the MCU is reset. Program run can be controlled by initializing

timer C by software before it reaches $FF.

• Timer output operation: The following four output modes can be selected for timer C by setting timer

mode register C2 (TMC2: $014).

Toggle

0 output

1 output

PWM output

By selecting the timer output mode, pin R3

1/TOC is set to TOC. The output from TOC is reset low by

MCU reset.

 Toggle output: When toggle output mode is selected, the output level is inverted if a clock is input

after timer C has reached $FF. By using this function and reload timer function, clock signals can

be output at a required frequency for the buzzer. The output waveform is shown in figure 33.

 PWM output: When PWM output mode is selected, timer C provides the variable-duty pulse output

function. The output waveform differs depending on the contents of timer mode register C1

(TMC1: $00D) and timer write register C (TWCL: $00E, TWCU: $00F). The output waveform is

shown in figure 33.

 0 output: When 0 output mode is selected, the output level is pulled low if a clock is input after

timer C has reached $FF. Note that this function must be used only when the output level is high.

 1 output: When 1 output mode is selected, the output level is set high if a clock is input after timer

C has reached $FF. Note that this function must be used only when the output level is low.

HD404324FS Datasheet(PDF) 51 Page - Renesas Technology Corp