Motorola DSP56301 - Manual (Page 279)

Operating Modes
Triple Timer Module 9 -17
Figure 9-14. Period Measurement Mode, TRM = 0
Mode 5 (internal clock): TRM = 0
N = write preload
M = write compare
TE
Clock
(CLK/2 or prescale CLK)
TLR
TCR
Counter
first event
M
0 N N + 1 M M + 1
N + 1
N
NOTE: If INV = 1, a 1-to-0 edge on TIO loads the counter, and a 0-to-1 edge on TIO
TCF (Compare Interrupt if TCIE = 1)
TIO pin
period being measured
loads TCR with count and the counter with N.
Interrupt Service
reads TCR; period
= M - N clock
periods
Counter continues
counting, does
not stop. Overflow
may occur (TOF=1).