Hitachi H8S/2215 Series, Hardware Manual

Page: 354 / 745

Rev. 3.0, 10/02, page 296 of 686
TCNT value
H'FFFF
H'0000
TIOCB
TIOCA
Time
TGRB
TGRA
Toggle output
Toggle output
Counter cleared by TGRB compare match
Figure 10.11 Example of Toggle Output Operation
Input Capture Function: The TCNT value can be transferred to TGR on detection of the TIOC
pin input edge. Rising edge, falling edge, or both edges can be selected as the detected edge. For
channels 0 and 1, it is also possible to specify another channel’s counter input clock or compare
match signal as the input capture source.
Note: When another channel’s counter input clock is used as the input capture input for channel
0, ø/1 should not be selected as the counter input clock used for input capture input.
Input capture will not be generated if ø/1 is selected.
1. Example of input capture operation setting procedure
Figure 10.12 shows an example of the input capture operation setting procedure.
Input selection
Select input capture input
Start count
<Input capture operation>
Designate TGR as an input capture register by
means of TIOR, and select rising edge, falling
edge, or both edges as the input capture source
and input signal edge.
Set the CST bit in TSTR to 1 to start the count
operation.
[1]
[2]
[1]
[2]
Figure 10.12 Example of Input Capture Operation Setting Procedure
2. Example of input capture operation
Figure 10.13 shows an example of input capture operation. In this example both rising and
falling edges have been selected as the TIOCA pin input capture input edge, falling edge has
been selected as the TIOCB pin input capture input edge, and counter clearing by TGRB input
capture has been designated for TCNT.