Software Standby Mode Application Example - Renesas H8S Series Hardware Manual

Table 21-4 shows the standby times for different operating frequencies and settings of bits STS2 to STS0.
Table 21-4 Oscillation Stabilization Time Settings
STS2 STS1 STS0 Standby Time
0 0
1
1 0
1
: Recommended time setting
Using an External Clock: Any value can be set. Normally, use of the minimum time is recommended.
Note: * The 16-state standby time cannot be used in the F-ZTAT version; a standby time of 8192 states or longer should
be used.
21.6.4

Software Standby Mode Application Example

Figure 21-2 shows an example in which a transition is made to software standby mode at the falling edge on the NMI pin,
and software standby mode is cleared at the rising edge on the NMI pin.
In this example, an NMI interrupt is accepted with the NMIEG bit in SYSCR cleared to 0 (falling edge specification), then
the NMIEG bit is set to 1 (rising edge specification), the SSBY bit is set to 1, and a SLEEP instruction is executed,
causing a transition to software standby mode.
Software standby mode is then cleared at the rising edge on the NMI pin.
Rev.6.00 Oct.28.2004 page 676 of 1016
REJ09B0138-0600H
0 8,192 states
1 16,384 states
0 32,768 states
1 65,536 states
0 131,072 states
1 262,144 states
Reserved
0
1 16 states
20 16 12 10
MHz MHz MHz MHz
0.41 0.51 0.68 0.8
0.82 1.0 1.3 1.6
1.6 2.0 2.7 3.3
3.3 4.1 5.5 6.6
6.6 8.2 10.9 13.1 16.4 21.8 32.8 65.5
13.1 16.4 21.8 26.2 32.8 43.6 65.6 131.2
— — — —
0.8 1.0 1.3 1.6
8 6 4 2
MHz MHz MHz MHz Unit
1.0 1.3 2.0 4.1
2.0 2.7 4.1 8.2
4.1 5.5 8.2 16.4
8.2 10.9 16.4 32.8
— — — —
2.0 2.7 4.0 8.0
ms
—
µs