h8s-2646 Renesas Electronics Corporation., h8s-2646 Datasheet - Page 751

• Manufacturer Part Number: h8s-2646
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2600 Series
• Manufacturer: Renesas Electronics Corporation.

20.12
In addition to its normal operating state, the flash memory has power-down states in which power
consumption is reduced by halting part or all of the internal power supply circuitry.
There are three flash memory operating states:
(1) Normal operating mode: The flash memory can be read and written to.
(2) Power-down mode: Part of the power supply circuitry is halted, and the flash memory can be
(3) Standby mode: All flash memory circuits are halted, and the flash memory cannot be read or
States (2) and (3) are flash memory power-down states. Table 20.22 shows the correspondence
between the operating states of the LSI and the flash memory.
Table 20.22 Flash Memory Operating States
20.12.1 Notes on Power-Down States
1. When the flash memory is in a power-down state, part or all of the internal power supply
2. In a power-down state, FLMCR1, FLMCR2, EBR1, EBR2, RAMER, and FLPWCR cannot be
LSI Operating State
High-speed mode
Medium-speed mode
Sleep mode
Subactive mode
Subsleep mode
Watch mode
Software standby mode
Hardware standby mode
read when the LSI is operating on the subclock.
written to.
circuitry is halted. Therefore, a power supply circuit stabilization period must be provided
when returning to normal operation. When the flash memory returns to its normal operating
state from a power-down state, bits STS2 to STS0 in SBYCR must be set to provide a wait
time of at least 20 µs (power supply stabilization time), even if an oscillation stabilization
period is not necessary.
read from or written to.
Flash Memory and Power-Down States
Flash Memory Operating State
Normal mode (read/write)
When PDWND = 0: Power-down mode (read-only)
When PDWND = 1: Normal mode (read-only)
Standby mode
Rev. 5.00 Sep 22, 2005 page 725 of 1136
REJ09B0257-0500
Section 20 ROM