X40014S8I-B Просмотр технического описания (PDF) - Xicor -> Intersil

Номер в каталоге

Компоненты Описание

производитель

X40014S8I-B

Dual Voltage Monitor with Integrated CPU Supervisor

Xicor -> Intersil 

X40010/X40011/X40014/X40015 – Preliminary

Figure 2. VTRIPX Set/Reset Conditions

VTRIPX

(X = 1, 2)

VCC/V2MON

VP

WDO

SCL

0

70

70

7

SDA

A0h

00h

tWC

WATCHDOG TIMER

The Watchdog Timer circuit monitors the microproces-

sor activity by monitoring the SDA and SCL pins. The

microprocessor must toggle the SDA pin HIGH to LOW

periodically, while SCL also toggles from HIGH to LOW

(this is a start bit) followed by a stop condition prior to

the expiration of the watchdog time out period to pre-

vent a WDO signal going active. The state of two non-

volatile control bits in the Status Register determines

the watchdog timer period. The microprocessor can

change these watchdog bits by writing to the X40010/

11/14/15 control register (also refer to page 19).

Figure 3. Watchdog Restart

.6µs

1.3µs

SCL

SDA

Timer Start

V1 AND V2 THRESHOLD PROGRAM PROCEDURE

(OPTIONAL)

The X40010/11/14/15is shipped with standard V1 and

V2 threshold (VTRIP1, VTRIP2) voltages. These values

will not change over normal operating and storage con-

ditions. However, in applications where the standard

thresholds are not exactly right, or if higher precision is

needed in the threshold value, the X40010/11/14/15trip

points may be adjusted. The procedure is described

below, and uses the application of a high voltage control

signal.

Setting a VTRIPx Voltage (x=1, 2)

There are two procedures used to set the threshold

voltages (VTRIPx), depending if the threshold voltage to

be stored is higher or lower than the present value. For

example, if the present VTRIPx is 2.9 V and the new

VTRIPx is 3.2 V, the new voltage can be stored directly

into the VTRIPx cell. If however, the new setting is to be

lower than the present setting, then it is necessary to

“reset” the VTRIPx voltage before setting the new value.

Setting a Higher VTRIPx Voltage (x=1, 2)

To set a VTRIPx threshold to a new voltage which is

higher than the present threshold, the user must apply

the desired VTRIPx threshold voltage to the corre-

sponding input pin Vcc(V1MON), or V2MON. The

Vcc(V1MON) and V2MON must be tied together during

this sequence. Then, a programming voltage (Vp) must

be applied to the WDO pin before a START condition is

set up on SDA. Next, issue on the SDA pin the Slave

Address A0h, followed by the Byte Address 01h for

VTRIP1 and 09h for VTRIP2, and a 00h Data Byte in

order to program VTRIPx. The STOP bit following a

valid write operation initiates the programming

sequence. Pin WDO must then be brought LOW to

complete the operation.

Note: This operation does not corrupt the memory

array.

REV 1.3.4 7/12/02

www.xicor.com

Characteristics subject to change without notice. 4 of 25

Share Link: