參數(shù)資料
型號(hào)： DS1986
廠商： Maxim Integrated Products, Inc.
英文描述： 64K bit Add-Only iButton(64K位只加按鈕)
中文描述： 64K位只添加iButton®
文件頁(yè)數(shù)： 12/24頁(yè)
文件大小： 164K
代理商： DS1986
DS1986
052298 12/24
WRITING EPROM MEMORY
The DS1986 has two independent EPROM memory
fields, Data Memory and Status Memory. The function
flow for writing either field is almost identical. After the
appropriate write command has been issued, the bus
master will send a two–byte starting address
(TA1=(T7:T0), TA2=(T15:T8)) and a byte of data
(D7:D0). A 16–bit CRC of the command byte, address
bytes, and data byte is computed by the DS1986 and
read back by the bus master to confirm that the correct
command word, starting address, and data byte were
received.
If the CRC read by the bus master is incorrect, a Reset
Pulse must be issued and the entire sequence must be
repeated. If the CRC received by the bus master is cor-
rect, a programming pulse (12 volts on the 1–Wire bus
for 480
μ
s) is issued by the bus master. Prior to program-
ming, the entire EPROM memory field will appear as
logical 1s. For each bit in the data byte provided by the
bus master that is set to a logical 0, the corresponding
bit in the selected byte of the EPROM memory is pro-
grammed to a logical 0 after the programming pulse has
been applied.
After the 480
μ
s programming pulse is applied and the
data line returns to the idle level (5 Volts), the bus master
issues eight read time slots to verify that the appropriate
bits have been programmed. The DS1986 responds
with the data from the selected EPROM address sent
least significant bit first. This byte contains the bitwise
logical AND of all data ever written to this address. If the
EPROM byte contains 1s in bit positions where the byte
issued by the master contained 0s, a Reset Pulse
should be issued and the current byte address should
be programmed again. If the DS1986 EPROM byte con-
tains 0s in the same bit positions as the data byte, the
programming was successful and the DS1986 will auto-
matically increment its address counter to select the
next byte in the EPROM memory field. The new two–
byte address will also be loaded into the 16–bit CRC
generator as a starting value. The bus master will issue
the next byte of data using eight write time slots.
As the DS1986 receives this byte of data into the
scratchpad, it also shifts the data into the CRC genera-
tor that has been preloaded with the current address
and the result is a 16–bit CRC of the new data byte and
the new address. After supplying the data byte, the bus
master will read this 16–bit CRC from the DS1986 with
sixteen read time slots to confirm that the address
incremented properly and the data byte was received
correctly. If the CRC is incorrect, a Reset Pulse must be
issued and the write sequence must be restarted. If the
CRC is correct, the bus master will issue a programming
pulse and the selected byte in memory will be pro-
grammed.
Note that the initial pass through the write flow chart will
generate an 16–bit CRC value that is the result of shift-
ing the command byte into the CRC generator, followed
by the two address bytes, and finally the data byte. Sub-
sequent passes through the write flow chart due to the
DS1986 automatically incrementing its address counter
will generate a 16–bit CRC that is the result of loading
(not shifting) the new (incremented) address into the
CRC generator and then shifting in the new data byte.
For both of these cases, the decision to continue (to
apply a program pulse to the DS1986) is made entirely
by the bus master, since the DS1986 will not be able to
determine if the 16–bit CRC calculated by the bus mas-
ter agrees with the 16–bit CRC calculated by the
DS1986. If an incorrect CRC is ignored and a program
pulse is applied by the bus master, incorrect program-
ming could occur within the DS1986. Also note that the
DS1986 will always increment its internal address
counter after the receipt of the eight read time slots used
to confirm the programming of the selected EPROM
byte. The decision to continue is again made entirely by
the bus master. Therefore if the EPROM data byte does
not match the supplied data byte but the master contin-
ues with the write command, incorrect programming
could occur within the DS1986. The write command
sequence can be ended at any point by issuing a Reset
Pulse.
相關(guān)PDF資料
PDF描述
DS2045W 3.3V Single-Piece 1Mb Nonvolatile SRAM
DS2045W-100 3.3V Single-Piece 1Mb Nonvolatile SRAM
DS2151Q T1 Single-Chip Transceiver(T1單片收發(fā)器)
DS2154 Enhanced E1 Single Chip Transceiver(改進(jìn)型E1單片收發(fā)器)
DS2164Q G.726 ADPCM Processor(G.726自適應(yīng)音頻脈沖編碼處理器)
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
DS1986+F3 制造商:Maxim Integrated Products 功能描述:ADD-O IBTN 64KB, F3 (GENERIC) LFREE - Rail/Tube
DS19860-F3-W 功能描述:iButton RoHS:否 存儲(chǔ)類型:SRAM 存儲(chǔ)容量:512 B 組織: 工作電源電壓:3 V to 5.25 V 接口類型:1-Wire 最大工作溫度:+ 85 C 尺寸:17.35 mm x 5.89 mm 封裝 / 箱體:F5 MicroCan 制造商:Maxim Integrated
DS1986-F3 功能描述:iButton RoHS:否 存儲(chǔ)類型:SRAM 存儲(chǔ)容量:512 B 組織: 工作電源電壓:3 V to 5.25 V 接口類型:1-Wire 最大工作溫度:+ 85 C 尺寸:17.35 mm x 5.89 mm 封裝 / 箱體:F5 MicroCan 制造商:Maxim Integrated
DS1986-F3# 功能描述:iButton RoHS:否 存儲(chǔ)類型:SRAM 存儲(chǔ)容量:512 B 組織: 工作電源電壓:3 V to 5.25 V 接口類型:1-Wire 最大工作溫度:+ 85 C 尺寸:17.35 mm x 5.89 mm 封裝 / 箱體:F5 MicroCan 制造商:Maxim Integrated
DS1986-F3+ 功能描述:iButton RoHS:否 存儲(chǔ)類型:SRAM 存儲(chǔ)容量:512 B 組織: 工作電源電壓:3 V to 5.25 V 接口類型:1-Wire 最大工作溫度:+ 85 C 尺寸:17.35 mm x 5.89 mm 封裝 / 箱體:F5 MicroCan 制造商:Maxim Integrated
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。

采購(gòu)需求

(若只采購(gòu)一條型號(hào)，填寫一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

*型號(hào) *數(shù)量 廠商 批號(hào) 封裝
添加更多采購(gòu)

我的聯(lián)系方式

*
*
*