DS1982 Datasheet, PDF (7/23 Pages) Dallas Semiconductor – 1-kbit Add-Only iButton

DS1982
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)
7 of 23