
Technical Data
MC68HC11E Family
—
Rev. 4
208
Timing System
MOTOROLA
Timing System
interrupt request is generated each time PAOVF is set. Before leaving
the interrupt service routine, software must clear PAOVF by writing to
the TFLG2 register.
PAII and PAIF
—
Pulse Accumulator Input Edge Interrupt Enable Bit
and Flag
The PAIF status bit is automatically set each time a selected edge is
detected at the PA7/PAI/OC1 pin. To clear this status bit, write to the
TFLG2 register with a 1 in the corresponding data bit position (bit 4).
The PAII control bit allows configuring the pulse accumulator input
edge detect for polled or interrupt-driven operation but does not affect
setting or clearing the PAIF bit. When PAII is 0, pulse accumulator
input interrupts are inhibited, and the system operates in a polled
mode. In this mode, the PAIF bit must be polled by user software to
determine when an edge has occurred. When the PAII control bit is
set, a hardware interrupt request is generated each time PAIF is set.
Before leaving the interrupt service routine, software must clear PAIF
by writing to the TFLG2 register.