ADP315PC87570 National Semiconductor, ADP315PC87570 Datasheet - Page 108

• Manufacturer Part Number: ADP315PC87570
• Description: Keyboard and Power Management Controller
• Manufacturer: National Semiconductor

14.3.5 Counter Clock Source Select
The clock source unit contains two clock source selectors
which allow you to independently select the clock source for
each of the two 16-bit counters from one of the following
sources:
•
•
•
•
•
Mode
1
2
3
4
No clock, in which case the counter is stopped
Prescaled system clock
External Event count based on TB
Pulse Accumulate mode based on TB
Slow Speed Clock i.e., 32.768 KHz
PWM and system
timer or external
event counter
Dual input capture
and system timer
Dual independent
timer
Input capture and
timer
Description
Counter for PWM
Capture A and B
time base
Time base for first
timer
Time base for first
timer
Timer/Counter 1
(
T
CNT1)
Multi-Function 16-Bit Timer (MFT16)
Table 14-1. Operation Modes
Auto Reload A =
PWM time I
Capture counter 1
value on
Reload register for
timer/counter I
Reload register for
timer/counter I
Reload/Capture A
108
(
T
14.4 TIMER/COUNTER AND ACTION UNIT
The timer/counter and action unit consists of two 16-bit
counters, TCNT1 and TCNT2, plus two 16-bit reload/cap-
ture registers, TCRA and TCRB. The timers are down
counters capable of triggering events on underflow detec-
tion (count from 0000h to FFFFh). In addition, it contains the
mode control logic which allows the timer to operate in any
of four operation modes described below.
Different interrupts can be triggered on certain conditions
and the functionality of the I/O pins change depending of the
mode of operation. Therefore the interrupt control and I/O
control are an integral part of the timer/counter unit.
14.4.1 Operation Modes
You can configure the MFT16 to operate in any one of four
modes, as summarized in Table 14-1 and described in this
section.
CRA)
T
A event
Auto reload = PWM
time II
Capture counter 1
value on
Reload register for
timer/counter II
Capture counter 1
value on
Reload/Capture B
(
T
CRB)
T
T
B event
B event
System Timer or
external event
counter
System Timer
Time base for
second timer
Capture B time
base
Timer/Counter 2
(
T
CNT2)
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