HD6413008F RENESAS [Renesas Technology Corp], HD6413008F Datasheet - Page 512

• Manufacturer Part Number: HD6413008F
• Description: Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Series
• Manufacturer: RENESAS [Renesas Technology Corp]

18. Power-Down State
18.5
18.5.1
Regardless of its current state, the chip enters hardware standby mode whenever the STBY pin
goes low. Hardware standby mode reduces power consumption drastically by halting all functions
of the CPU, and on-chip supporting modules. All modules are reset except the on-chip RAM. As
long as the specified voltage is supplied, on-chip RAM data is retained. I/O ports are placed in the
high-impedance state.
Clear the RAME bit to 0 in SYSCR before STBY goes low to retain on-chip RAM data.
The inputs at the mode pins (MD2 to MD0) should not be changed during hardware standby
mode.
18.5.2
Hardware standby mode is exited by inputs at the STBY and RES pins. While RES is low, when
STBY goes high, the clock oscillator starts running. RES should be held low long enough for the
clock oscillator to settle. When RES goes high, reset exception handling begins, followed by a
transition to the program execution state.
18.5.3
Figure 18.2 shows the timing relationships for hardware standby mode. To enter hardware standby
mode, first drive RES low, then drive STBY low. To exit hardware standby mode, first drive
STBY high, wait for the clock to settle, then bring RES from low to high.
Rev.4.00 Aug. 20, 2007 Page 468 of 638
REJ09B0395-0400
Timing for Hardware Standby Mode
Hardware Standby Mode
Transition to Hardware Standby Mode
Exit from Hardware Standby Mode