DM-COP8/20D National Semiconductor, DM-COP8/20D Datasheet - Page 63

• Manufacturer Part Number: DM-COP8/20D
• Description: CABLE FOR DEBUG MODULE 20-DIP
• Manufacturer: National Semiconductor

Specifications of DM-COP8/20D

• Accessory Type: 20-DIP Target Cable
• For Use With/related Products: MetaLink Debug Module
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: *DM-COP8/20D

flexibility of interrupting once per PWM period on either the rising or falling edge of the
PWM output. Alternatively, the user may choose to interrupt on both edges of the PWM
output.
Mode 2. External Event Counter Mode
This mode is quite similar to the processor independent PWM mode described above. The
main difference is that the timer, T1, is clocked by the input signal from the T1A pin. The
T1 timer control bits, T1C3, T1C2 and T1C1 allow the timer to be clocked either on a
positive or negative edge from the T1A pin. Underflows from the timer are latched into
the T1PNDA pending flag. Setting the T1ENA control flag will cause an interrupt when
the timer underflows.
In this mode the input pin T1B can be used as an independent positive edge sensitive
interrupt input if the T1ENB control flag is set. The occurrence of a positive edge on the
T1B input pin is latched into the T1PNDB flag.
Figure 2-16 shows a block diagram of the timer in External Event Counter mode.
NOTE:
Mode 3. Input Capture Mode
The device can precisely measure external frequencies or time external events by placing
the timer block, T1, in the input capture mode.In this mode, the reload registers serve as
independent capture registers, capturing the contents of the timer when an external
event occurs (transition on the timer input pin). The capture registers can be read while
maintaining count, a feature that lets the user measure elapsed time and time between
events. By saving the timer value when the external event occurs, the time of the
The PWM output is not available in this mode since the T1A pin is being
used as the counter input clock.
Figure 2-16 Timer in External Event Counter Mode
TO INTERRUPT CONTROL
RELOAD REGISTER
RELOAD REGISTER
16 BIT TIMER/
16 BIT AUTO
16 BIT AUTO
COUNTER
OFF TIME
ON TIME
EDGE SELECTOR
LOGIC
COP8SAx7 MICROCONTROLLER
TIMER
UNDERFLOW
INTERRUPTS
EXT
CLK
T1A
T1B
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