Jameco Electronics 2000, 3000 manual Input Capture Channels, 4.Rabbit Timers A and B

Models: 3000 2000

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Figure 2-4. Rabbit Timers A and B

perclk

Timer A System

 

perclk

A1

 

 

Serial E

 

 

 

A2

perclk/2

 

 

 

Serial F

 

 

 

 

 

 

 

 

A3

 

 

 

 

Serial A

 

 

 

 

A4

 

 

 

Input

Serial B

 

A8

 

A5

 

 

Capture

 

 

 

 

 

 

Serial C

 

 

 

 

 

A9

 

PWM

A6

 

 

 

Serial D

 

 

 

Quadrature

 

A10

A7

 

Decode

 

 

 

 

Timer A1

 

 

 

 

perclk/2

10-bit counter

 

perclk/8

 

10 bits

compare

 

 

Timer_B1

 

match reg

Control Timer

Timer B System

 

 

 

 

Synchronized

 

 

 

 

 

match preload

outputs

 

 

 

 

 

 

Timer_B2

 

match reg

 

 

match preload

 

 

Figure 2-4. Rabbit Timers A and B

2.2.9 Input Capture Channels

The input capture channels are used to determine the time at which an event takes place. An event is signaled by a rising or falling edge (or optionally by either edge) on one of 16 input pins that can be selected as input for either of the two channels. A 16 bit counter is used to record the time at which the event takes place. The counter is driven by the output of Timer A8 and can be set to count at a rate ranging from full clock speed to 1/256 the clock speed.

Two events are recognized: a start condition and a stop condition. The start condition may be used to start counting and the stop condition to stop counting. However the counter may also run continuously or run until a stop condition is encountered. The start and stop conditions may also be used to latch the current time at the instant the condition occurs rather than actually start or stop the counter. The same pin may be used to detect the start

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Rabbit 3000 Microprocessor

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Jameco Electronics 2000, 3000 manual Input Capture Channels, 4.Rabbit Timers A and B