COP888EB Datasheet, PDF (17/75 Pages) National Semiconductor (TI) – 8-Bit CMOS ROM Based Microcontrollers with 8k Memory, CAN Interface, 8-Bit A/D, and USART

Timers (Continued)
sequently, the TxC0 control bit should be reset when enter-
ing the Input Capture mode. The timer underflow interrupt is
enabled with the TxENA control flag. When a TxA interrupt
occurs in the Input Capture mode, the user must check both
whether a TxA input capture or a timer underflow (or both)
caused the interrupt.
Figure 11 shows a block diagram of the timer in Input Cap-
ture mode.
FIGURE 11. Timer in Input Capture Mode
TIMER CONTROL FLAGS
The control bits and their functions are summarized below.
TxC3 Timer mode control
TxC2 Timer mode control
TxC1 Timer mode control
TxC0
Timer Start/Stop control in Modes 1 and 2 (Pro-
cessor Independent PWM and External Event
Counter), where 1 = Start, 0 = Stop
Timer Underflow Interrupt Pending Flag in
Mode 3 (Input Capture)
TxPNDA Timer Interrupt Pending Flag
TxENA Timer Interrupt Enable Flag
1 = Timer Interrupt Enabled
0 = Timer Interrupt Disabled
TxPNDB Timer Interrupt Pending Flag
TxENB Timer Interrupt Enable Flag
1 = Timer Interrupt Enabled
0 = Timer Interrupt Disabled
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