DS1982 Просмотр технического описания (PDF) - Maxim Integrated

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производитель

DS1982

1Kb Add-Only iButton

Maxim Integrated 

DS1982

MEMORY FUNCTION COMMANDS

The “Memory Function Flow Chart” (Figure 6) describes the protocols necessary for accessing the

various data fields within the DS1982. The Memory Function Control section, 8-bit scratchpad, and the

Program Voltage Detect circuit combine to interpret the commands issued by the bus master and create

the correct control signals within the device. A 3-byte protocol is issued by the bus master. It is comprised

of a command byte to determine the type of operation and 2 address bytes to determine the specific

starting byte location within a data field. The command byte indicates if the device is to be read or

written. Writing data involves not only issuing the correct command sequence but also providing a 12-

volt programming voltage at the appropriate times. To execute a write sequence, a byte of data is first

loaded into the scratchpad and then programmed into the selected address. Write sequences always occur

a byte at a time. To execute a read sequence, the starting address is issued by the bus master and data is

read from the part beginning at that initial location and continuing to the end of the selected data field or

until a reset sequence is issued. All bits transferred to the DS1982 and received back by the bus master

are sent least significant bit first.

DS1982 MEMORY MAP Figure 5

1024-BIT

EPROM

STARTING

ADDRESS

0000h

0020h

0040h

0060h

8-BIT SCRATCHPAD

PAGE 0

32 BYTES

PAGE 1

32 BYTES

PAGE 2

32 BYTES

PAGE 3

32 BYTES

ADDRESS:

EPROM STATUS BYTES

0007h 0006h

(MSB)

0005h

0004h

0003h

0002h

0001h

0000h

(LSB)

BIT 0

BIT 1

BIT 2

BIT 3

BIT 4-7

WRITE PROTECT PAGE 0

WRITE PROTECT PAGE 1

WRITE PROTECT PAGE 2

WRITE PROTECT PAGE 3

BITMAP OF USED PAGES (RESERVED FOR TMEX)

Page 7 of 24

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