DS1972 Maxim, DS1972 Datasheet - Page 10

• Manufacturer Part Number: DS1972
• Description: The DS1972 is a 1024-bit, 1-Wire® EEPROM chip organized as four memory pages of 256 bits each in a rugged iButton® package
• Manufacturer: Maxim

1024-Bit EEPROM iButton
Figure 7a. Memory Function Flowchart
10
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INCREMENTS
BUS MASTER
DS1972
Rx "1"s
E[2:0]
N
N
AND DATA BYTES AS THEY
BUS MASTER Tx MEMORY
TA1 (T[7:0]), TA2 (T[15:8])
WERE SENT BY THE BUS
MASTER Tx DATA BYTE
FUNCTION COMMAND
COMMAND, ADDRESS,
WRITE SCRATCHPAD?
DS1972 Tx CRC-16 OF
SETS E[2:0] = T[2:0]
MASTER Tx RESET?
MASTER Tx RESET?
TO SCRATCHPAD
BUS MASTER Tx
CLEARS AA = 0
SETS PF = 1
E[2:0] = 7?
T[2:0] = 0?
MASTER
DS1972
PF = 0
0Fh
FLOWCHART (FIGURE 9)
TO ROM FUNCTIONS
Y
N
Y
Y
Y
N
Y
N
APPLIES ONLY
IF THE MEMORY
AREA IS NOT
PROTECTED.
IF WRITE PROTECTED,
THE DS1972 COPIES
THE DATE BYTE FROM
THE TARGET ADDRESS
INTO THE SCRATCHPAD.
IF IN EPROM MODE,
THE DS1972 LOADS
THE BITWISE LOGICAL
AND OF THE TRANSMITTED
BYTE AND THE DATA
BYTE FROM THE TARGETED
ADDRESS INTO THE
SCRATCHPAD.
FROM ROM FUNCTIONS
FLOWCHART (FIGURE 9)
BYTE COUNTER
INCREMENTS
BUS MASTER
DS1972
Rx "1"s
N
N
E/S BYTE, AND DATA BYTES
TA1 (T[7:0]), TA2 (T[15:8]),
OF COMMAND, ADDRESS,
AS SENT BY THE DS1972
BUS MASTER Rx CRC-16
BYTE COUNTER = T[2:0]
READ SCRATCHPAD?
MASTER Tx RESET?
MASTER Tx RESET?
DATA BYTE FROM
BUS MASTER Rx
BUS MASTER Rx
BYTE COUNTER
AND E/S BYTE
SCRATCHPAD
SCRATCHPAD
DS1972 SETS
= E[2:0]?
AAh
Y
N
Y
Y
N
Y
FROM FIGURE 7b
TO FIGURE 7b