Hitachi SH7751 Hardware Manual page 335

Bit 8—Underflow Flag (UNF): Status flag that indicates the occurrence of underflow.
Bit 8: UNF
0
1
Note: * Writing 1 does not change the value.
Bits 7 and 6—Input Capture Control (ICPE1, ICPE0) (Channel 2 Only): These bits, provided
in channel 2 only, specify whether the input capture function is used, and control enabling or
disabling of interrupt generation when the function is used.
When the input capture function is used, a data transfer request is sent to the DMAC in the event
of input capture.
When using the input capture function, the TCLK pin must be designated as an input pin with the
TCOE bit in the TOCR register. The CKEG bits specify whether the rising edge or falling edge of
the TCLK signal is used to set the TCNT2 value in the input capture register (TCPR2).
The TCNT2 value is set in TCPR2 only when the TCR2.ICPF bit is 0. When the TCR2.ICPF bit is
1, TCPR2 is not set in the event of input capture. When input capture occurs, a DMAC transfer
request is generated regardless of the value of the TCR2.ICPF bit. However, a new DMAC
transfer request is not generated until processing of the previous request is finished.
Bit 7: ICPE1 Bit 6: ICPE0
0 0
1
1 0
1
Bit 5—Underflow Interrupt Control (UNIE): Controls enabling or disabling of interrupt
generation when the UNF status flag is set to 1, indicating TCNT underflow.
Rev. 3.0, 04/02, page 296 of 1064
Description
TCNT has not underflowed
[Clearing condition]
When 0 is written to UNF
TCNT has underflowed
[Setting condition]
When TCNT underflows*
Description
Input capture function is not used
Reserved (Do not set)
Input capture function is used, but interrupt due to input capture
(TICPI2) is not enabled
Data transfer request is sent to DMAC in the event of input
capture
Input capture function is used, and interrupt due to input
capture (TICPI2) is enabled
Data transfer request is sent to DMAC in the event of input
capture
(Initial value)
(Initial value)