XE8805 SEMTECH [Semtech Corporation], XE8805 Datasheet - Page 146

• Manufacturer Part Number: XE8805
• Description: Data Acquisition MCU
• Manufacturer: SEMTECH [Semtech Corporation]

Table 20-12 shows the different operation modes of the counters C and D as a function of the mode control bits.
For all counter modes, the source of the down or upcount selection is given (either the bit CntCDownUp or the bit
CntDDownUp). The mapping of the interrupt sources IrqC and IrqD and the PWM output on PB(1) in these
different modes is also shown.
The switching between different modes must be done while the concerned counters are stopped. While switching
capture mode on and off, unwanted interrupts can appear on the interrupt channels concerned by this mode
change.
20.9 Counter / Timer mode
The counters in counter / timer mode are generally used to generate interrupts after a predefined number of clock
periods applied on the counter clock input.
Each counter can be set individually either in upcount mode by setting CntXDownUp in the register
RegCntConfig1 or in downcount mode by resetting this bit. Counters A and B can be cascaded to behave as a 16
bit counter by setting CascadeAB in the RegCntConfig1 register. Counters C and D can be cascaded by setting
CascadeCD. When cascaded, the up/down count modes of the counters B and D are defined respectively by the
up/down count modes set for the counters A and C.
© Semtech 2006
CascadeCD
CascadeAB
0
1
0
1
0
1
0
0
1
0
1
CountPWM0
0
0
1
1
0
0
1
CapFunc(1:0)
CountPWM1
Table 20-11: Operating modes of the counters A and B
Table 20-12: Operating modes of the counters C and D
0
0
1
1
00
00
00
00
1x
x1
1x
x1
1x
x1
or
or
or
Counter 8b
Captured counter 16b AB
Counter A
Downup: A
Downup: A
counter 8b
Counter C
Counter 8b
Downup: C
Captured
PWM 8b
PWM 8b
PWM 8b
mode
Down
Down
mode
Down
PWM 10 – 16b AB
PWM 10 – 16b CD
Counter 16b AB
Counter 16b CD
Downup: A
Downup: A
Downup: C
Down
Down
20-6
Counter 8b
Counter 8b
Counter B
Downup: B
Downup: B
Downup: B
counter 8b
counter 8b
Captured
Captured
Counter 8b
Downup: D
Counter 8b
Counter D
mode
Down
mode
Down
Must not
Counter
Counter
Capture
Capture
be used
source
Counter
Counter
Source
IrqA
AB
AB
A
A
IrqC
-
-
CD
C
-
-
Counter
Counter
Capture
Capture
Capture
source
Counter
Counter
source
IrqB
AB
IrqD
B
B
B
B
-
-
D
D
-
-
PWM AB
function
XE8805/05A
PWM CD
PWM A
PWM A
function
PWM C
PB(0)
PB(0)
PB(0)
PB(0)
PB(0)
PB(1)
PB(1)
PB(1)
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