32186 datasheet(874/1032 Pages) RENESAS

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RAM BACKUP MODE

19-2

32185/32186 Group Hardware Manual

Rev.1.10 REJ09B0235-0110 May 15, 07

19.1 Outline of RAM Backup Mode

In RAM backup mode, the part of contents of the internal RAM are retained while the power is turned off.

RAM backup mode is used for the following two purposes.

RAM back up area for the 32185/32186 is from H'0080 4000 to H'0080 7FFF(16KB).

• Back up the part of the internal RAM data when the power is forcibly turned off from the outside (RAM

backup when the power is off)

• For the M32R/ECU to turn off the power to the CPU at any time as needed to reduce the system’s power

consumption while retaining part of the internal RAM data (RAM backup for saving the power consumption)

The M32R/ECU is placed in RAM backup mode by applying a voltage of 3.3 V or 5.0 V to the VDDE pin

(provided for RAM backup) and 0 V to all other pins. When started by boot mode, internal RAM value is

indefinite after started by boot mode in order to "Flash writing/ Erase program" is transferd to internal RAM.

During RAM backup mode, the contents of the internal RAM are retained, while the CPU and internal periph-

eral I/O remain idle. Because all pins except VDDE are held low during RAM backup mode, the power

consumption in the system can effectively be reduced.

Figure 19.1.1 RAM Backup Area

H'0080 4000

H'0080 7FFF

H'0080 8000

H'0080 BFFF

RAM backup area (16KB)

32185 internal RAM (32KB)

Non-RAM backup area

H'0080 4000

H'0080 7FFF

H'0080 8000

H'0081 3FFF

RAM backup area (16KB)

32186 internal RAM (64KB)

Non-RAM backup area

32186 Datasheet(PDF) 874 Page - Renesas Technology Corp