參數(shù)資料
型號(hào)： X4645V8I
元件分類： EEPROM
英文描述： CPU Supervisor with 64K EEPROM
中文描述： CPU監(jiān)控與64K的EEPROM的
文件頁(yè)數(shù)： 3/22頁(yè)
文件大小： 408K
代理商： X4645V8I
X4643/5 – Preliminary Information
Characteristics subject to change without notice.
3 of 22
REV 1.26 4/30/02
www.xicor.com
PRINCIPLES OF OPERATION
Power On Reset
Application of power to the X4643/5 activates a Power
On Reset Circuit that pulls the RESET/RESET pin
active. This signal provides several benefits.
– It prevents the system microprocessor from starting
to operate with insufficient voltage.
– It prevents the processor from operating prior to sta-
bilization of the oscillator.
– It allows time for an FPGA to download its configura-
tion prior to initialization of the circuit.
– It prevents communication to the EEPROM, greatly
reducing the likelihood of data corruption on power up.
When V
CC
exceeds the device V
for 200ms (nominal) the circuit releases RESET/
RESET allowing the system to begin operation.
TRIP
threshold value
LOW VOLTAGE MONITORING
During operation, the X4643/5 monitors the V
and asserts RESET/RESET if supply voltage falls
below a preset minimum V
signal prevents the microprocessor from operating in a
power fail or brownout condition. The RESET/RESET
signal remains active until the voltage drops below 1V.
It also remains active until V
V
TRIP
for 200ms.
CC
level
TRIP
. The RESET/RESET
CC
returns and exceeds
WATCHDOG TIMER
The Watchdog Timer circuit monitors the microprocessor
activity by monitoring the SDA and SCL pins. The
microprocessor must toggle the SDA pin HIGH to LOW
periodically, while SCL is HIGH (this is a start bit) prior
to the expiration of the watchdog time out period to
prevent a RESET/RESET signal. The state of two non-
volatile control bits in the Status Register determine
the watchdog timer period. The microprocessor can
change these watchdog bits, or they may be “l(fā)ocked”
by tying the WP pin HIGH.
EEPROM INADVERTENT WRITE PROTECTION
When RESET/RESET goes active as a result of a low
voltage condition or Watchdog Timer Time Out, any in-
progress communications are terminated. While
RESET/RESET is active, no new communications are
allowed and no nonvolatile write operation can start.
Nonvolatile writes in-progress when RESET/RESET
goes active are allowed to finish.
Additional protection mechanisms are provided with
memory Block Lock and the Write Protect (WP) pin.
These are discussed elsewhere in this document.
V
CC
THRESHOLD RESET PROCEDURE
The X4643/5 is shipped with a standard V
(V
TRIP
) voltage. This value will not change over normal
operating and storage conditions. However, in applica-
tions where the standard V
TRIP
higher precision is needed in the V
X4643/5 threshold may be adjusted. The procedure is
described below, and uses the application of a nonvol-
atile control signal.
CC
threshold
is not exactly right, or if
TRIP
value, the
Figure 1. Set V
TRIP
Level Sequence (V
CC
= desired V
TRIP
values WEL bit set)
0 1 2 3 4 5 6 7
SCL
SDA
A0h
0 1 2 3 4 5 6 7
00h
WP
V
P
= 12-15V
0 1 2 3 4 5 6 7
01h
0 1 2 3 4 5 6 7
00h
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X4645V8I-2.7 功能描述:IC SUPERVISOR CPU 64K EE 8-TSSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 監(jiān)控器 系列:- 標(biāo)準(zhǔn)包裝:100 系列:- 類型:簡(jiǎn)單復(fù)位/加電復(fù)位 監(jiān)視電壓數(shù)目:1 輸出:- 復(fù)位:低有效 復(fù)位超時(shí):最小為 100 ms 電壓 - 閥值:4.38V 工作溫度:0°C ~ 70°C 安裝類型:表面貼裝 封裝/外殼:8-TSSOP（0.173"，4.40mm 寬） 供應(yīng)商設(shè)備封裝:8-TSSOP 包裝:管件
X4645V8I-2.7A 功能描述:IC SUPERVISOR CPU 64K EE 8-TSSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 監(jiān)控器 系列:- 標(biāo)準(zhǔn)包裝:100 系列:- 類型:簡(jiǎn)單復(fù)位/加電復(fù)位 監(jiān)視電壓數(shù)目:1 輸出:- 復(fù)位:低有效 復(fù)位超時(shí):最小為 100 ms 電壓 - 閥值:4.38V 工作溫度:0°C ~ 70°C 安裝類型:表面貼裝 封裝/外殼:8-TSSOP（0.173"，4.40mm 寬） 供應(yīng)商設(shè)備封裝:8-TSSOP 包裝:管件
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