AT32F425
Series Reference Manual
2022.03.30
Page 192
Ver 2.01
Note: The delay between the signal on the input side and the actual clock of the counter is due to the
synchronization circuit.
Figure 14-9
Counting in external clock mode A
30
COUNTER
OVFIF
TMR_CLK
110
STIS[2:0]
Clear
CNT_CLK
C2IRAW
000
C2IF[2:0]
31
32
0
1
2
3
4
Figure 14-10
Block diagram of external clock mode B
CK_DIV
Slave mode
control
External clock
control
EXT
Divider
Filterr
Downcounter
Polarity
selection
Note: The delay between the EXT signal on the input side and the actual clock of the counter is due to
the synchronization circuit.
Figure 14-11
Counting in external clock mode B
30
COUNTER
OVFIF
TMR_CLK
00
ESDIV[1:0]
Clear
CNT_CLK
EXT
0000
ESF[3:0]
31
32
0
1
2
3
4
Internal trigger input (ISx)
Timer synchronization allows interconnection between several timers. The TMR_CLK of one timer can
be provided by the TRGOUT signal output by another timer. Set the STIS[2: 0] bit to select internal
trigger signal to enable counting.
Each timer (TMR2 to TMR5) consists of a 16-bit prescaler, which is used to generate the CK_CNT that
enables the counter to count. The frequency division relationship between the CK_CNT and TMR_CLK
can be adjusted by setting the value of the TMRx_DIV register. The prescaler value can be modified at
any time, but it takes effect only when the next overflow event occurs.