HD404324FS datasheet(47/103 Pages) RENESAS

47 / 103 page

HD404054 Series/HD404094 Series

Timers

The MCU has three timer/counters (A, C, and D).

• Timer A: Free-running timer

• Timer C: Multifunction timer

• Timer D: Multifunction timer

Timer A is an 8-bit free-running timer. Timers C and D are 8-bit multifunction timers, whose functions are

listed in table 23. The operating modes are selected by software.

Timer A

Timer A Functions: Timer A has the following functions.

• Free-running timer

The block diagram of timer A is shown in figure 30.

Timer A Operations:

• Free-running timer operation: The input clock for timer A is selected by timer mode register A (TMA:

$008).

Timer A is reset to $00 by MCU reset and incremented at each input clock. If an input clock is applied

to timer A after it has reached $FF, an overflow is generated, and timer A is reset to $00. The overflow

sets the timer A interrupt request flag (IFTA: $001, bit 2). Timer A continues to be incremented after

reset to $00, and therefore it generates regular interrupts every 256 clocks.

Registers for Timer A Operation: Timer A operating modes are set by the following registers.

• Timer mode register A (TMA: $008): Four-bit write-only register that selects timer A’s operating mode

and input clock source as shown in figure 31.

HD404324FS Datasheet(PDF) 47 Page - Renesas Technology Corp