Appendix E Timing of Transition to and Recovery from
Hardware Standby Mode
Timing of Transition to Hardware Standby Mode
(1) To retain RAM contents with the RAME bit set to 1 in SYSCR, drive the
RES
signal low 10
system clock cycles before the
STBY
signal goes low, as shown below.
RES
must remain low
until
STBY
goes low (minimum delay from
STBY
low to
RES
high: 0 ns).
(2) To retain RAM contents with the RAME bit cleared to 0 in SYSCR, or when RAM contents
do not need to be retained,
RES
does not have to be driven low as in (1).
Timing of Recovery from Hardware Standby Mode: Drive the
RES
signal low approximately
100 ns before
STBY
goes high.
855
t
1
≥
10t
cyc
t
2
≥
0 ns
STBY
RES
STBY
RES
t
≥
100 ns
t
OSC
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