Fujitsu MB89950/950A Pager User Manual


 
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CHAPTER 8 PULSE WIDTH COUNT TIMER (PWC)
8.3 Structure of Pulse Width Count Timer
This section describes the pins, pin block diagram, registers, and interrupt source of
the pulse width count timer.
Pulse width count timer pin
The pulse width count timer uses the P42/PWC/INT1 pin. This pin can function either as CMOS general-
purpose I/O port (P42) or external interrupt (INT1), or as the measured pulse input (PWC).
PWC:
The pulse width measurement function measures the pulse widths input to this pin.
Set the pin as an input port in the port data direction register (DDR4: bit 2 = "0") when using as the
PWC pin for the pulse width measurement function.
Block diagram of pulse width count timer pin
Figure 8.3-1 Block diagram of pulse width count timer pin
PDR (Port data register)
DDR
Internal data bus
PDR read
PDR read
Output latch
PDR write
DDR write
Pin
SPL: Pin state specification bit in the standby control register (STBC)
N-c
P42/PWC/INT1
h
Stop mode (SPL = 1)
To peripheral input
(Port data direction register)
P-ch
Pull-up resistor
Approx. 50 k
P-ch
(When Read-modify-write instruction executed)
Stop mode (SPL = 1)
To external interrupt
External interrupt enable
(Mask option)