Does the RES# pin need to be set to low level in order to enter hardware standby mode?
No, the RES# pin does not need to be set to low level beforehand. However, if the STBY# pin is set to low, the MCU will switch to hardware standby mode and the internal clock to asynchronous, regardless of MCU operating state. Consequently, if, for example, the STBY# pin were set to low while the CPU was in the process of accessing on-chip RAM, that data could be lost. There are two methods for preserving on-chip RAM contents, detailed as follows: 1) Switch to standby mode after stopping the CPU from accessing on-chip RAM by setting the RAME bit to 0 before setting the STBY# pin to low; and 2) Set the RES# pin to low before setting the STBY# pin to low . In addition, as long as the prescribed voltage (RAM standby voltage) is received in hardware standby mode, RAM contents will be preserved.
|H8S/2630, 2639, 2638, 2636, 2635|
|H8S/2556, 2552, 2506|
|H8S/2258, 2239, 2238, 2237, 2227|