HD404358 Datasheet, PDF (46/102 Pages) Renesas Technology Corp – microcomputer has an A/D converter,

HD404358 Series
Timer A
Timer A Functions: Timer A has the following functions.
• Free-running timer
The block diagram of timer A is shown in figure 29.
Timer A interrupt
request flag
(IFTA)
System
clock
ø_PER
Clock
Selector
Prescaler S (PSS)
Timer
counter A
(TCA) ^Overflow
3
Timer mode
register A
(TMA)
Figure 29 Timer A Block Diagram
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 30.
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