3069RF-ZTAT Datasheet, PDF (988/1003 Pages) Renesas Technology Corp – RENESAS 16-BIT SINGLE-CHIP MICROCOMPUTER

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).
STBY
RES
t₁ ≥ 10t_cyc
t₂ ≥ 0 ns
2. To retain RAM contents with the RAME bit cleared to 0 in SYSCR, 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.
STBY
RES
t ≥ 100 ns
t_OSC
Rev. 5.0, 09/04, page 966 of 978