ST7FMC1K2B3 STMICROELECTRONICS [STMicroelectronics], ST7FMC1K2B3 Datasheet - Page 71

• Manufacturer Part Number: ST7FMC1K2B3
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

ON-CHIP PERIPHERALS (Cont’d)
Input capture function
This mode allows the measurement of external
signal pulse widths through ARTICRx registers.
Each input capture can generate an interrupt inde-
pendently on a selected input signal transition.
This event is flagged by a set of the corresponding
CFx bits of the Input Capture Control/Status regis-
ter (ARTICCSR).
These input capture interrupts are enabled
through the CIEx bits of the ARTICCSR register.
The active transition (falling or rising edge) is soft-
ware programmable through the CSx bits of the
ARTICCSR register.
The read only input capture registers (ARTICRx)
are used to latch the auto-reload counter value
when a transition is detected on the ARTICx pin
(CFx bit set in ARTICCSR register). After fetching
the interrupt vector, the CFx flags can be read to
identify the interrupt source.
Note: After a capture detection, data transfer in
the ARTICRx register is inhibited until it is read
(clearing the CFx bit).
The timer interrupt remains pending while the CFx
flag is set when the interrupt is enabled (CIEx bit
set). This means, the ARTICRx register has to be
read at each capture event to clear the CFx flag.
The timing resolution is given by auto-reload coun-
ter cycle time (1/f
Note: During Halt mode, if both input capture and
external clock are enabled, the ARTICRx register
value is not guaranteed if the input capture pin and
the external clock change simultaneously.
Figure 43. Input Capture Timing Diagram
ICRx REGISTER
ARTICx PIN
COUNTER
CFx FLAG
COUNTER
f
COUNTER
).
01h
02h
xxh
03h
04h
External interrupt capability
This mode allows the Input capture capabilities to
be used as external interrupt sources. The inter-
rupts are generated on the edge of the ARTICx
signal.
The edge sensitivity of the external interrupts is
programmable (CSx bit of ARTICCSR register)
and they are independently enabled through CIEx
bits of the ARTICCSR register. After fetching the
interrupt vector, the CFx flags can be read to iden-
tify the interrupt source.
During Halt mode, the external interrupts can be
used to wake up the micro (if the CIEx bit is set).
05h
INTERRUPT
04h
06h
07h
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