TIMER/EVENT COUNTER MODES OF OPERATION
7 - 10
DSP56002 TIMER AND EVENT COUNTER
MOTOROLA
During the clock cycle following the point where the counter reaches 0, the TS bit in TCSR is set
and, if the TIE is set, an interrupt is generated.The counter is reloaded with the value contained
by the TCR and the entire process is repeated until the timer is disabled (TE=0). Each time the
counter reaches 0, the TIO output pin will be toggled. The INV bit determines the polarity of the
TIO output. Figure 7-7 illustrates Timer Mode 2.
7.5.4
Timer Mode 4 (Pulse Width Measurement Mode)
Timer Mode 4 is defined by TC2-TC0 equal 100.
In this mode, TIO acts as a gating signal for the DSP’s internal clock. With the timer en-
abled (TE=1), the counter is driven by a clock derived from the DSP’s internal clock divided
TE
TCR
Write Preload (N)
N
Counter
N
0
N
Interrupt
First Event
Last Event
N-1
TIO
New Event
2xCLK
N-1
Clock (CLK/2)
Figure 7-5 Standard Timer Mode, Internal Clock, Output Pulse Enabled (INV=0)
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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Содержание DSP56002
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