DSP56303 FREESCALE [Freescale Semiconductor, Inc], DSP56303 Datasheet - Page 207

• Manufacturer Part Number: DSP56303
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

9.3.2.3 Measurement Capture (Mode 6)
In Mode 6, the timer counts the number of clocks that elapse between when the timer starts and
when an external signal is received. At the first appropriate transition of the external clock
detected on the
interrupt is generated. The counter halts. The contents of the counter are loaded into the TCR.
The value of the TCR represents the delay between the setting of the TCSR[TE] bit and the
detection of the first clock edge signal on the
whether a high-to-low (1 to 0) or low-to-high (0 to 1) transition of the external clock signals the
end of the timing period. If the INV bit is set, a high-to-low transition signals the end of the
timing period. If INV is cleared, a low-to-high transition signals the end of the timing period.
Freescale Semiconductor
TC3
0
TCF (Compare Interrupt if TCIE = 1)
Mode 6 (internal clock): TRM = 1
N = write preload
M = write compare
TE
Clock
(CLK/2 or prescale CLK)
TLR
Counter
TCR
TIO pin
NOTE: If INV = 1, a 1-to-0 edge on TIO loads TCR with count and stops the counter.
TC2
Bit Settings
1
TIO
TC1
1
signal, TCSR[TCF] is set and, if the TCSR[TCIE] bit is set, a compare
Figure 9-15. Capture Measurement Mode, TRM = 0
TC0
N
0
0
Mode
delay being measured
first event
6
DSP56303 User’s Manual, Rev. 2
N
TIO
Capture
Name
signal. The value of the INV bit determines
N + 1
Mode Characteristics
Measurement
M
Function
M
N
Interrupt Service
reads TCR; delay
= M - N clock
periods
Counter stops
counting; overflow
may occur before
capture (TOF = 1)
Input
TIO
N + 1
Operating Modes
Internal
Clock
9-15