32186 datasheet(876/1032 Pages) RENESAS

876 / 1032 page

RAM BACKUP MODE

19-4

32185/32186 Group Hardware Manual

Rev.1.10 REJ09B0235-0110 May 15, 07

(a)

(b)

(c)

"L"

VREF0

SBI#

AD0INi

M32R/ECU

VCC

VDD

VBB

VREF

DC IN

(5V or 3.3V)

VDDE

AVCC0

OUT

VCCE,

VCCER

EXCVCC

EXCVDD

VCC-

BUS

(Note 2)

Backup battery

Reference voltage for

power outage detection

Power outage

detection signal

Backup power supply

for power outage

Power supply monitor IC

Note 1: Power outage is detected by the DC IN (regulator input) voltage.

Note 2: These pins are used to detect a RAM backup signal.

Note 3: This pin outputs "H" when the power is on and outputs "L" when the power is off.

Note 4: Determined by the input level on SBI# pin or AD0INi pin.

Note 5: The time needed for processing in (b) is secured by adjusting the capacitance.

Input

Output

Regulator

(Note 3)

(Note 1)

(Note 5)

3.3V or 5.0V

Example of RAM backup processing

Power goes off

(Note 4)

Create data for

backup RAM check

RAM backup mode

19.2 Example of RAM Backup when Power is Off

19.2.2 RAM Backup State

Figure 19.2.3 shows the power outage RAM backup state of the M32R/ECU. When the power supply goes

off, the power supply monitor IC starts feeding current from the backup battery to the M32R/ECU. Also, the

power supply monitor IC’s power outage detection pin outputs "L," causing the SBI# pin or AD0INi pin to go

"L," which generates a RAM backup signal ((a) in Figure 19.2.3). Determination of whether the power is off

must be made with respect to the DC IN (regulator input) voltage in order to allow for a software processing

time at power outage.

To enable RAM backup mode, make the following setting:

(1) Create data for RAM check to verify whether the RAM data has been retained normally after

returning from RAM backup mode to normal mode ((b) in Figure 19.2.3).

If the power supply to VCCE goes off after making above setting, the VDDE pin voltage goes to 3.0–3.3 V and all

other pin voltages drop to 0 V, and the M32R/ECU is thereby placed in RAM backup mode ((c) in Figure 19.2.3).

Figure 19.2.3 Power Outage RAM Backup State

32186 Datasheet(PDF) 876 Page - Renesas Technology Corp

32186 Datasheet(HTML) 876 Page - Renesas Technology Corp

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL