參數(shù)資料
型號(hào): 21C01SC
廠商: Microchip Technology Inc.
英文描述: 1K 5.0V IIC serial EEPROMs for smart card(1K位,5.0V,ISO7816標(biāo)準(zhǔn),EEPROM)
中文描述: 一千5.0V進(jìn)口證的智能卡(每1000位和5.0V,符合ISO7816標(biāo)準(zhǔn),EEPROM的串行EEPROM)
文件頁(yè)數(shù): 6/12頁(yè)
文件大?。?/td> 84K
代理商: 21C01SC
24C01SC/02SC
DS21170A-page 6
Preliminary
1996 Microchip Technology Inc.
6.0
ACKNOWLEDGE POLLING
Since the device will not acknowledge during a write
cycle, this can be used to determine when the cycle is
complete (this feature can be used to maximize bus
throughput). Once the stop condition for a write com-
mand has been issued from the master, the device ini-
tiates the internally timed write cycle. ACK polling can
be initiated immediately. This involves the master send-
ing a start condition followed by the control byte for a
write command (R/W = 0). If the device is still busy with
the write cycle, then NO ACK will be returned. If the
cycle is complete, then the device will return the ACK,
and the master can then proceed with the next read or
write command. See Figure 6-1 for flow diagram.
FIGURE 6-1:
ACKNOWLEDGE POLLING
FLOW
Send
Write Command
Send Stop
Condition to
Initiate Write Cycle
Send Start
Send Control Byte
with R/W = 0
Did Device
Acknowledge
(ACK = 0)
Next
Operation
NO
YES
7.0
READ OPERATION
Read operations are initiated in the same way as write
operations with the exception that the R/W bit of the
slave address is set to one. There are three basic types
of read operations: current address read, random read,
and sequential read.
7.1
Current Address Read
The 24C01SC/02SC contains an address counter that
maintains the address of the last word accessed, inter-
nally incremented by one. Therefore, if the previous
access (either a read or write operation) was to address
n, the next current address read operation would
access data from address n + 1. Upon receipt of the
slave address with R/W bit set to one, the
24C01SC/02SC 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
24C01SC/02SC
discontinues
(Figure 8-2).
transmission
7.2
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
24C01SC/02SC as part of a write operation. After the
word address is sent, the master generates a start con-
dition 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
24C01SC/02SC will then issue an acknowledge and
transmits the 8-bit data word. The master will not
acknowledge the transfer but does generate a stop con-
dition and the 24C01SC/02SC discontinues transmis-
sion (Figure 8-3).
7.3
Sequential Read
Sequential reads are initiated in the same way as a ran-
dom read except that after the 24C01SC/02SC trans-
mits the first data byte, the master issues an
acknowledge as opposed to a stop condition in a ran-
dom read. This directs the 24C01SC/02SC to transmit
the next sequentially addressed 8-bit word (Figure 9-1).
To provide sequential reads the 24C01SC/02SC con-
tains 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.
相關(guān)PDF資料
PDF描述
21C02SC 2K 5.0V IIC serial EEPROMs for smart card(2K位,5.0V,ISO7816標(biāo)準(zhǔn),EEPROM)
21DQ03 SBD
21FQ035 30 AMP SCHOTTKY RECTIFIER
21FQ040 30 AMP SCHOTTKY RECTIFIER
21FQ045 30 AMP SCHOTTKY RECTIFIER
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
21C15DCA 制造商:NDK 制造商全稱:NDK 功能描述:10.7 MHz- and 21.4 MHz-Series MCF
21C-21-M29 制造商:Kings Electronics 功能描述:
21C30DG 制造商:NDK 制造商全稱:NDK 功能描述:10.7 MHz- and 21.4 MHz-Series MCF
21C7.5DD 制造商:NDK 制造商全稱:NDK 功能描述:10.7 MHz- and 21.4 MHz-Series MCF
21C8238G04 制造商:GECO 功能描述: