- 您现在的位置：买卖IC网 > PDF目录67987 > MCP79402-I/MNY REAL TIME CLOCK, PDSO8 PDF资料下载
参数资料
| 型号： | MCP79402-I/MNY |
| 元件分类： | 时钟/数据恢复及定时提取 |
| 英文描述： | REAL TIME CLOCK, PDSO8 |
| 封装： | 2 X 3 MM, 0.75 MM WIDTH, ROHS COMPLIANT, PLASTIC, TDFN-8 |
| 文件页数： | 13/40页 |
| 文件大小： | 817K |
| 代理商： | MCP79402-I/MNY |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页当前第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页第38页第39页第40页
MCP7940X
DS25009B-page 20
2011 Microchip Technology Inc.
FIGURE 5-3:
ID BYTE WRITE
5.2.2
READ OPERATION
Read operations are initiated in the same way as write
operations with the exception that the R/W bit of the
control byte is set to one. There are three basic types
of read operations: current address read, random read,
and sequential read. The SRAM array can be read in
the same way as the ID using the control byte for the
SRAM ‘1101111’ with a valid address.
5.2.2.1
Current Address Read
The MCP7940X contains an address counter that
maintains the address of the last word accessed,
internally incremented by one. Therefore, if the
previous read access was to address n (n is any legal
address), the next current address read operation
would access data from address n + 1.
Upon receipt of the control byte with R/W bit set to one,
the MCP7940X issues an Acknowledge and transmits
the 8-bit data word. The master will not acknowledge
the transfer but does generate a Stop condition and the
MCP7940X discontinues transmission (Figure 5-4).
FIGURE 5-4:
CURRENT ADDRESS
READ (ID SHOWN)
5.2.2.2
Random Read
Random read operations allow the master to access
any memory location in a random manner. To perform
this type of read operation, first the word address must
be set. This is done by sending the word address to the
MCP7940X as part of a write operation (R/W bit set to
‘0’). After the word address is sent, the master
generates a Start condition following the Acknowledge.
This terminates the write operation, but not before the
internal Address Pointer is set. Then, the master issues
the control byte again but with the R/W bit set to a one.
The MCP7940X will then issue an Acknowledge and
transmit the 8-bit data word. The master will not
acknowledge the transfer but it does generate a Stop
condition which causes the MCP7940X to discontinue
transmission (Figure 5-5). After a random read
command, the internal address counter will point to the
address location following the one that was just read.
5.2.2.3
Sequential Read
Sequential reads are initiated in the same way as a
random read except that after the MCP7940X transmits
the first data byte, the master issues an Acknowledge
as opposed to the Stop condition used in a random
read. This Acknowledge directs the MCP7940X to
transmit the next sequentially addressed 8-bit word
(Figure 5-6). Following the final byte transmitted to the
master, the master will NOT generate an Acknowledge
but will generate a Stop condition. To provide
sequential reads, the MCP7940X contains an internal
Address Pointer which is incremented by one at the
completion of each operation. This Address Pointer
allows the entire memory contents to be serially read
during one operation. The internal Address Pointer will
automatically roll over to the start of the block.
BUS ACTIVITY
MASTER
SDA LINE
BUS ACTIVITY
S
T
A
R
T
CONTROL
BYTE
ADDRESS
BYTE
DATA
S
T
O
P
A
C
K
A
C
K
A
C
K
S 101 0
0
1 11
P
1 11 1 0
BUS ACTIVITY
MASTER
SDA LINE
BUS ACTIVITY
P
S
T
O
P
CONTROL
BYTE
S
T
A
R
T
DATA
A
C
K
N
O
A
C
K
11
00
1
BYTE
11 1
1 1 11 0
相关PDF资料 |
PDF描述 |
|---|---|
| MCP79402T-I/MNY | REAL TIME CLOCK, PDSO8 |
| MCP79400-I/ST | REAL TIME CLOCK, PDSO8 |
| MCP79401T-I/ST | REAL TIME CLOCK, PDSO8 |
| MCP79401-I/MNY | REAL TIME CLOCK, PDSO8 |
| MCP7940NT-I/MNY | REAL TIME CLOCK, PDSO8 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MCP79402T-I/MNY | 功能描述:实时时钟 I2C GP RTCC 64B SRAM EUI-64 RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 总线接口:I2C 日期格式:DW:DM:M:Y 时间格式:HH:MM:SS RTC 存储容量:64 B 电源电压-最大:5.5 V 电源电压-最小:1.8 V 最大工作温度:+ 85 C 最小工作温度: 安装风格:Through Hole 封装 / 箱体:PDIP-8 封装:Tube |
| MCP79402T-I/MS | 功能描述:实时时钟 I2C GP RTCC 64B SRAM EUI-64 RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 总线接口:I2C 日期格式:DW:DM:M:Y 时间格式:HH:MM:SS RTC 存储容量:64 B 电源电压-最大:5.5 V 电源电压-最小:1.8 V 最大工作温度:+ 85 C 最小工作温度: 安装风格:Through Hole 封装 / 箱体:PDIP-8 封装:Tube |
| MCP79402T-I/SN | 功能描述:实时时钟 I2C GP RTCC 64B SRAM EUI-64 RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 总线接口:I2C 日期格式:DW:DM:M:Y 时间格式:HH:MM:SS RTC 存储容量:64 B 电源电压-最大:5.5 V 电源电压-最小:1.8 V 最大工作温度:+ 85 C 最小工作温度: 安装风格:Through Hole 封装 / 箱体:PDIP-8 封装:Tube |
| MCP79402T-I/ST | 功能描述:实时时钟 I2C GP RTCC 64B SRAM EUI-64 RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 总线接口:I2C 日期格式:DW:DM:M:Y 时间格式:HH:MM:SS RTC 存储容量:64 B 电源电压-最大:5.5 V 电源电压-最小:1.8 V 最大工作温度:+ 85 C 最小工作温度: 安装风格:Through Hole 封装 / 箱体:PDIP-8 封装:Tube |
| MCP7940M | 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:Low-Cost I2Ca?￠ Real-Time Clock/Calendar with SRAM |
发布紧急采购，3分钟左右您将得到回复。