Electronics America Computer Hardware User Manual

171
Chapter 7 Timer/Counter Units
7
Fig. 7-75 External Event Count Timing of 8-Bit Timer/Counter 2
(1) When occurrences of one edge are counted (maximum frequency = f
CLK
/24)
Remark ICI: CI input signal after passing through the edge detector
(2) When occurrences of both edges are counted (maximum frequency = f
CLK
/32)
Count
clock of
TM2
Dn + 2
32/fCLK(Min.)
16/f
CLK(Min.)
16/f
CLK(Min.)
16/f
CLK
(constant)
CI
ICI
Countable
timing of
TM2
TM2
Dn + 1
Dn
Dn + 3 Dn + 4 Dn + 5
8-12/fCLK
Remark ICI: CI input signal after passing through the edge detector
CI
ICI
Count
clock of
TM2
Countable
timing
of TM2
TM2
Dn
Dn + 1 Dn + 2
Dn + 3
16/fCLK
(constant)
12/fCLK(Min.) 12/fCLK(Min.) 24/fCLK(Min.)
8-12/fCLK