TMP86FS49FG datasheet(20/42 Pages) TOSHIBA

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2. Operational Description

2.2 System Clock Controller

TMP86FS49FG

When the STOP pin input is high, executing an instruction which starts 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 two methods can be used for confirmation.

1. Testing a port P20.

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

Figure 2-7 Level-sensitive Release Mode

Note 1: In this case of changing to the level-sensitive mode from the edge-sensitive mode, the release

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

(2) Edge-sensitive release mode (RELM = “0”)

In this mode, STOP mode is released by a rising edge of the STOP pin input. This is used in appli-

cations where a relatively short program is executed repeatedly at periodic intervals. This periodic

signal (for example, a clock from a low-power consumption oscillator) is input to the STOP pin. In

the edge-sensitive release mode, STOP mode is started even when the STOP pin input is high level.

Example 1 :Starting STOP mode from NORMAL mode by testing a port P20.

(SYSCR1), 01010000B

; Sets up the level-sensitive release mode

SSTOPH:

TEST

(P2PRD). 0

; Wait until the STOP pin input goes low level

JRS

F, SSTOPH

; IMF

← 0

SET

(SYSCR1). 7

; Starts STOP mode

Example 2 :Starting STOP mode from NORMAL mode with an INT5 interrupt.

PINT5:

TEST

(P2PRD). 0

; To reject noise, STOP mode does not start if

JRS

F, SINT5

port P20 is at high

(SYSCR1), 01010000B

; Sets up the level-sensitive release mode.

; IMF

← 0

SET

(SYSCR1). 7

; Starts STOP mode

SINT5:

RETI

Example :Starting STOP mode from NORMAL mode

; IMF

← 0

(SYSCR1), 10010000B

; Starts after specified to the edge-sensitive release mode

VIH

NORMAL

operation

Warm up

STOP

operation

Confirm by program that the

STOP pin input is low and start

STOP mode.

Always released if the STOP

pin input is high.

STOP pin

XOUT pin

STOP mode is released by the hardware.

NORMAL

operation

TENTATIVE

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