h8s-2628 Renesas Electronics Corporation., h8s-2628 Datasheet - Page 552

• Manufacturer Part Number: h8s-2628
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2600 Series
• Manufacturer: Renesas Electronics Corporation.

Section 21 Power-Down Modes
21.5
21.5.1
When the
In hardware standby mode, all functions enter the reset state and stop operation, resulting in a
significant reduction in power consumption. As long as the prescribed voltage is supplied, on-chip
RAM data is retained. I/O ports are set to the high-impedance state.
In order to retain on-chip RAM data, the RAME bit in SYSCR should be cleared to 0 before
driving the
Do not change the state of the mode pins (MD2 to MD0) while this LSI is in hardware standby
mode.
21.5.2
Hardware standby mode is cleared by means of the
pin is driven high while the
Ensure that the
settling time when using a crystal oscillator). When the
transition is made to the program execution state via the reset exception handling state.
21.5.3
Timing of Transition to Hardware Standby Mode
1. To retain RAM contents with the RAME bit set to 1 in SYSCR
Rev. 3.00 Oct 04, 2005 page 512 of 598
REJ09B0155-0300
Drive the
figure 21.4. After
Transition to Hardware Standby Mode
Clearing Hardware Standby Mode
Hardware Standby Mode Timings
Hardware Standby Mode
S T B Y
STBY
RES
S T B Y
R E S
R E S
Figure 21.4 Timing of Transition to Hardware Standby Mode
pin is driven low, a transition is made to hardware standby mode from any mode.
pin low.
signal low at least 10 states before the
pin is held low until the clock oscillator settles (at least 8 ms the oscillation
S T B Y
R E S
has gone low,
pin is low, the reset state is set and clock oscillation is started.
t
1
R E S
10 t
cyc
has to wait for at least 0 ns before becoming high.
S T B Y
t
2
0 ns
S T B Y
R E S
pin and the
pin is subsequently driven high, a
signal goes low, as shown in
R E S
pin. When the
S T B Y