The AS7C34098A is a high-performance CMOS 4,194,304-bit Static Random Access Memory (SRAM) device organized as
262,144 words × 16 bits. It is designed for memory applications where fast data access, low power, and simple interfacing are
desired.
Equal address access and cycle times (t
AA
, t
RC
, t
WC
) of 10/12/15/20 ns with output enable access times (t
OE
) of 4/5/6/7 ns are
ideal for high-performance applications. The chip enable input CE permits easy memory expansion with multiple-bank
memory systems.
When CE is high the device enters standby mode. The device is guaranteed not to exceed 28.8mW power consumption in
CMOS standby mode. A write cycle is accomplished by asserting write enable (WE) and chip enable (CE). Data on the input
pins I/O1–I/O16 is written on the rising edge of WE (write cycle 1) or CE (write cycle 2). To avoid bus contention, external
devices should drive I/O pins only after outputs have been disabled with output enable (OE) or write enable (WE).
A read cycle is accomplished by asserting output enable (OE) and chip enable (CE), with write enable (WE) high. The chip
drives I/O pins with the data word referenced by the input address. When either chip enable or output enable is inactive, or
write enable is active, output drivers stay in high-impedance mode.
The device provides multiple center power and ground pins, and separate byte enable controls, allowing individual bytes to be
written and read. LB controls the lower bits, I/O1–I/O8, and UB controls the higher bits, I/O9–I/O16.
All chip inputs and outputs are TTL- and CMOS-compatible, and operation is for 3.3V (AS7C34098A) supply. The device is
available in the JEDEC standard 400-mil, 44-pin SOJ, TSOP 2.
Absolute maximum ratings
Parameter
Voltage on V
CC
relative to GND
Voltage on any pin relative to GND
Power dissipation
Storage temperature (plastic)
Ambient temperature with V
CC
applied
DC current into outputs (low)
Symbol
V
t1
V
t2
P
D
T
stg
T
bias
I
OUT
Min
–0.50
–0.50
–
–65
–55
–
Max
+5.0
V
CC
+0.50
1.5
+150
+125
±20
Unit
V
V
W
°C
°C
mA
Note: Stresses greater than those listed under
Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress rating only
and functional operation of the device at these or any other conditions outside those indicated in the operational sections of this specification is not
implied. Exposure to absolute maximum rating conditions for extended periods may affect reliability.
Truth table
CE
H
L
L
WE
X
H
X
OE
X
H
X
LB
X
X
H
L
L
H
L
H
L
L
L
L
X
H
L
Key: X = Don’t care, L = Low, H = High.
UB
X
X
High Z
H
H
L
L
H
L
L
D
OUT
High Z
D
OUT
D
IN
High Z
D
IN
High Z
D
OUT
D
OUT
High Z
D
IN
D
IN
Write (I
CC
)
Read (I
CC
)
High Z
Output disable (I
CC
)
I/O1–I/O8
High Z
I/O9–I/O16
High Z
Mode
Standby (I
SB
, I
SB1
)
11/14/11,v. 2.2
Alliance Memory Inc
P. 2 of 11
AS7C34098A
®
Recommended operating conditions
Parameter
Supply voltage
Input voltage
Ambient operating temperature
commercial
industrial
Symbol
V
CC
(10/12/15/20)
V
IH**
V
IL*
T
A
T
A
Min Typical
3.0
2.0
–0.5
0
–40
3.3
–
–
–
–
Max
3.6
V
CC
+ 0.5
0.8
70
85
Unit
V
V
V
°C
°C
* V min = –1.0V for pulse width less than 5ns.
IL
*
V
IH
max = V
CC
+ 2.0V for pulse width less than 5ns.
DC operating characteristics (over the operating range)
LWIP是一款开源的嵌入式网络协议栈，支持的功能很多，而且能在多任务环境下和单任务裸机环境下跑，今天说说他的移植过程，芯片为STM32，网卡为ENC28J60，无操作系统 首先下载LWIP的源代码，我下载的是1.4.1的源码，下载后解压，文件结构如图 将这四个目录中的文件全部拷贝到工程中，A PI 是一些socket通讯的接口，需要在多任务的环境下实现，core里面存放的内核源码，我们主要...[详细]
工控电子
