TMP88CS38FG datasheet(14/226 Pages) TOSHIBA

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TMP88CS38/CM38A/CP38A

2007-09-12

88CS38-14

1.4.4

Operating Mode Control

(1) STOP mode

STOP mode is controlled by the system control register 1 (SYSCR1) and the STOP

pin input. The STOP pin is also used both as a port P20 and an INT5 (External

interrupt input 5) pin. STOP mode is started by setting STOP (Bit7 in SYSCR1 ) to “1”.

During STOP mode, the following status is maintained.

1. Oscillations are turned off, and all internal operations are halted.

2. The data memory, registers and port output latches are all held in the status in

effect before STOP mode was entered.

3. The prescaler and the divider of the timing generator are cleared to “0”.

4. The program counter holds the address of the instruction following the instruction

which started the STOP mode.

STOP mode includes a level-sensitive release mode and an edge-sensitive release

mode, either of which can be selected with RELM (Bit6 in SYSCR1).

a. Level-sensitive release mode (RELM

= 1)

In this mode, STOP mode is released by setting the STOP pin high. This mode

is used for capacitor backup when the main power supply is cut off and long term

battery backup.

When the STOP pin input is high, executing an instruction which starts the

STOP mode will not place in STOP mode but instead will immediately start the

release sequence (Warm up). Thus, to start STOP mode in the level-sensitive

release mode, it is necessary for the program to first confirm that the STOP pin

input is low. The following method can be used for confirmation:

Using an external interrupt input INT5 ( INT5 is a falling edge-sensitive input).

Example: Starting STOP mode with an INT5 interrupt.

PINT5:

TEST

(P2). 0

;

JRS

F, SINT5

To reject noise, the STOP mode does not start if port

P20 is at high

(SYSCR1), 01010000B

;

Sets up the level-sensitive release mode

SET

(SYSCR1). 7

;

Starts STOP mode

LDW

(IL), 1110011101010111B

;

IL12, 11, 7, 5, 3 ← 0 (Clears interrupt latches)

SINT5:

RETI

Note 1:

After warming up is started, when STOP pin input is changed “L” level, STOP mode is not placed.

Note 2:

When changing to the level-sensitive release mode from the edge-sensitive release mode, the release

mode is not switched until a rising edge of the STOP pin input is detected.

Figure 1.4.9 Level-sensitive Release Mode

STOP

XOUT pin

NORMAL

operation

Confirm by program that the

STOP

pin input is low and

start STOP mode.

VIH

STOP mode is released by the hardware.

Always released if the STOP

pin input is high.

NORMAL

operation

STOP

operation

Warm up

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