X40410V8-C datasheet(4/24 Pages) RENESAS

4 / 24 page

X40410, X40411, X40414, X40415

FN8116 Rev 0.00

Page 4 of 24

March 28, 2005

Figure 2. VTRIPX Set/Reset Conditions

WATCHDOG TIMER

The Watchdog Timer circuit monitors the microprocessor

activity by monitoring the SDA and SCL pins. The micro-

processor must toggle the SDA pin HIGH to LOW periodi-

cally, 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 prevent a WDO signal

going active. The state of two nonvolatile control bits in the

Status Register determines the watchdog timer period. The

microprocessor can change these watchdog bits by writing

to the X40410/11/14/15 control register (also refer to page

19).

Figure 3. Watchdog Restart

V1 AND V2 THRESHOLD PROGRAM PROCEDURE

(OPTIONAL)

The X40410/11/14/15is shipped with standard V1 and

V2 threshold (VTRIP1, VTRIP2) voltages. These values will

not change over normal operating and storage condi-

tions. However, in applications where the standard

thresholds are not exactly right, or if higher precision is

needed in the threshold value, the X40410/11/14/15 trip

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 volt-

ages (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.

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

In order to set VTRIPx to a lower voltage than the present

value, then VTRIPx must first be “reset” according to the

procedure described below. Once VTRIPx has been

“reset”, then VTRIPx can be set to the desired voltage

using the procedure described in “Setting a Higher

VTRIPx Voltage”.

VCC/V2MON

VTRIPX

tWC

A0h

SCL

WDO

SDA

(X = 1, 2)

00h

SCL

SDA

.6µs

1.3µs

Timer Start

X40410V8-C bảng dữ liệu(PDF) 4 Page - Renesas Technology Corp

X40410V8-C bảng dữ liệu(HTML) 4 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

bảng dữ liệu tải về

Link URL