177
2. Block diagram
Figure 9.1 shows a block diagram of timer A.
ø
PSW
Internal data bus
PSS
Notation:
TMOW
1/4
TMA
CWORS
TCA
ø
W
/32
ø
W
/16
ø
W
/8
ø
W
/4
ø/32
ø/16
ø/8
ø/4
ø /128
W
ø/8192, ø/4096, ø/2048,
ø/512, ø/256, ø/128,
ø/32, ø/8
IRRTA
÷
8
*
÷
64
*
÷
128
*
÷
256
*
ø /4
W
TMA:
TCA:
IRRTA:
PSW:
PSS:
CWOSR:
Note:
*
Can be selected only when the prescaler W output (ø
W
/128) is used as the TCA input clock.
Timer mode register A
Timer counter A
Timer A overflow interrupt request flag
Prescaler W
Prescaler S
Subclock output select register
W
ø
Figure 9.1 Block Diagram of Timer A
3. Pin configuration
Table 9.2 shows the timer A pin configuration.
Table 9.2
Pin Configuration
Name
Abbrev.
I/O
Function
Clock output
TMOW
Output
Output of waveform generated by timer A output circuit