Hitachi H8S/2646 Hardware Manual page 391

Examples of Phase Counting Mode Operation: In phase counting mode, TCNT counts up or
down according to the phase difference between two external clocks. There are four modes,
according to the count conditions.
• Phase counting mode 1
Figure 10-29 shows an example of phase counting mode 1 operation, and table 10-9
summarizes the TCNT up/down-count conditions.
TCLKA (channels 1 and 5)
TCLKC (channels 2 and 4)
TCLKB (channels 1 and 5)
TCLKD (channels 2 and 4)
TCNT value
Figure 10-29 Example of Phase Counting Mode 1 Operation
Table 10-9 Up/Down-Count Conditions in Phase Counting Mode 1
TCLKA (Channels 1 and 5)
TCLKC (Channels 2 and 4)
High level
Low level
High level
Low level
Legend
: Rising edge
: Falling edge
Up-count
TCLKB (Channels 1 and 5)
TCLKD (Channels 2 and 4)
Low level
High level
High level
Low level
Down-count
Time
Operation
Up-count
Down-count
359