Motorola DSP56301 user manual Mode 4 internal clock TRM = 1 first event

					Operating Modes
Mode 4 (internal clock): TRM = 1		first event
N = write preload
M = write compare
TE
Clock
(CLK/2 or prescale CLK)
TLR	N
Counter	0	N	N + 1		M
					N + 1
					Next 0-to-1 edge
TCR				M	on TIO loads
					counter and
					process repeats
TIO pin		width being measured
					Interrupt Service
TCF (Compare Interrupt if TCIE = 1)					reads TCR; width
					= M - N clock
					periods

NOTE: If INV = 1, a 1-to-0 edge on TIO loads the counter, and a 0-to-1 edge on TIO stops the counter and loads TCR with the count.

Figure 9-11.Pulse Width Measurement Mode, TRM = 1

Mode 4 (internal clock): TRM = 1 first event

N = write preload

M = write compare

TE

Clock

(CLK/2 or prescale CLK)

TLR	N
Counter	0

TCR

TIO pin

N N + 1 M

M

width being measured

Next 0-Nto-+1 1edge on TIO starts counter from current count and process repeats. Overflow may occur (TOF = 1).

Interrupt Service

TCF (Compare Interrupt if TCIE = 1)

NOTE: If INV = 1, a 1-to-0 edge on TIO loads the counter, and a 0-to-1 edge on TIO stops the counter and loads TCR with the count.

reads TCR for accumulated width

of M - N clock periods.

Figure 9-12.Pulse Width Measurement Mode, TRM = 0

Triple Timer Module 9-15