DS1977 Maxim, DS1977 Datasheet - Page 12

• Manufacturer Part Number: DS1977
• Description: The DS1977 is a 32KB EEPROM in a rugged iButton® enclosure
• Manufacturer: Maxim

Figure 7-2. MEMORY/CONTROL FUNCTION FLOW CHART
From Figure 7
1
To Figure 7
1
st
st
Part
Part
Access Password
Holding Register
Save to Full-
N
Y
Passw.?
Access
Read-
Password Holding
Save to Read
More data
Register
in SP?
N
Y
N
Holding Register (if Password
Data or Data from Password
DS1977 Copies Scratchpad
Y
TA1 (T7:T0), TA2 (T15:T8)
Address) to Memory
64-Bits [Password]
Master Activates
DS1977 TX "0"
DS1977 TX "1"
Code Match?
Copy Scrpad.
Authorization
Strong Pullup
Accepted?
TX Reset?
TX Reset?
Strong Pull-
12 of 29
Password?
Master TX
Master TX
Password
Address of
Master TX
E/S Byte
up Valid?
[w/PW]
AA = 1
Master
Master
99h
N
Y
Y
Y
N
Y
Y
N
N
N
Y
N
NOTE: The strong pullup
must be activated within
40µs after the last bit of the
password is transmitted.
Pullup duration: see t
Authorization
Code
Master RX "1"s
TX Reset?
Master
Y
From Figure 7
SPUW
To Figure 7
N
3rd Part
3
rd
Part
DS1977