pc87591l National Semiconductor Corporation, pc87591l Datasheet - Page 141

• Manufacturer Part Number: pc87591l
• Description: Lpc Mobile Embedded Controllers
• Manufacturer: National Semiconductor Corporation

Revision 1.07
Embedded Controller Modules
4.7.5
There are two I/O pins associated with each of the MFT16 modules: TAn and TBn, where n denotes the module on a given
device. The functionality of TA and TB depends on the mode of operation and the value of TAEN and TBEN bits. Table 20
shows the function of TA and TB versus the selected mode of operation. Note that if TA functions as a PWM output, the
initial and present value of TA is defined by TAOUT. For example, to start with TA high, TAOUT must be set (1) prior to
enabling the timer clock.
4.7.6
The MFT16 supports freezing the counters during breakpoints while operating in development systems. If FREEZE bit is
asserted, all timer counter clocks are inhibited, and the current values of timer/counter registers TnCNT1 and TnCNT2 are
frozen. Once FREEZE becomes inactive, counting resumes from the previous value. See 4.20.5 on page 273 for more de-
tails.
TBn
TAn
I/O
Timer I/O Functions
Operation in Development System
TnBEN=X
TnBEN=X
TnAEN=X
TnAEN=X
TnAEN=0
TnAEN=1
TnBEN=0
TnBEN=1
TnAEN
TnBEN
underflow of TnCNT1
PWM and Counter
Ext. Event or Pulse
Ext. Event or Pulse
Toggle Output on
Accumulate Input
Accumulate Input
No Output
Mode 1
Table 20. MFT16 I/O Functions
(Continued)
Dual Input Capture
Capture TnCNT1
Capture TnCNT1
Capture TnCNT1
Capture TnCNT1
into TnCRA and
into TnCRB and
preset TnCNT1
preset TnCNT1
into TnCRA
into TnCRB
Mode 2
141
underflow of TnCNT1
Ext. Event or Pulse
Ext. Event or Pulse
Dual Independent
Accumulate Input
Accumulate Input
No Output toggle
Toggle Output on
Mode 3
Timer
underflow of TnCNT1
Input Capture and
No Output toggle
Toggle Output on
Capture TnCNT2
Capture TnCNT2
into TnCRB and
preset TnCNT2
into TnCRB
Mode 4
Timer
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