Application Notes - Hitachi H8/3827R Series Hardware Manual

6. Timer G operation modes
Timer G operation modes are shown in table 9.13.
Table 9.13 Timer G Operation Modes
Operation Mode
TCG Input capture
Interval
ICRGF
ICRGR
TMG
Note: * When øw/4 is selected as the TCG internal clock in active mode or sleep mode, since the
system clock and internal clock are mutually asynchronous, synchronization is maintained
by a synchronization circuit. This results in a maximum count cycle error of 1/ø (s). When
øw/4 is selected as the TCG internal clock in watch mode, TCG and the noise canceler
operate on the øw/4 internal clock without regard to the ø
Note that when another internal clock is selected, TCG and the noise canceler do not
operate, and input of the input capture input signal does not result in input capture.
To be operated Timer G in subactive mode or subsleep mode, select øw/4 for internal clock
of TCG and also select øw/2 for sub clock ø
and when another sub clock (øw/8, øw/4) is selected, TCG and noise canceler do not
operate.
9.5.5

Application Notes

1. Internal clock switching and TCG operation
Depending on the timing, TCG may be incremented by a switch between difference internal clock
sources. Table 9.14 shows the relation between internal clock switchover timing (by write to bits
CKS1 and CKS0) and TCG operation.
When TCG is internally clocked, an increment pulse is generated on detection of the falling edge
of an internal clock signal, which is divided from the system clock (ø) or subclock (øw). For this
reason, in a case like No. 3 in table 9.14 where the switch is from a high clock signal to a low
clock signal, the switchover is seen as a falling edge, causing TCG to increment.
224
Reset Active Sleep
Reset Functions* Functions* Functions/
Reset Functions* Functions* Functions/
Reset Functions* Functions* Functions/
Reset Functions* Functions* Functions
Reset Functions Held
Sub- Sub-
Watch active sleep
Functions/ Functions/
halted* halted* halted*
Functions/ Functions/
halted* halted* halted*
Functions/ Functions/
halted* halted* halted*
Functions/ Functions/
halted* halted* halted*
Held Functions Held
subclock (øw/8, øw/4, øw/2).
SUB
. When another internal clock is selected
SUB
Module
Standby Standby
Halted Halted
Halted Halted
Held Held
Held Held
Held Held