DS1977 Maxim, DS1977 Datasheet - Page 11

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

Figure 7-1. MEMORY/CONTROL FUNCTION FLOW CHART
ments Scratch-
DS1977 Incre-
pad Offset
N
Y
Y
TA1 (T7:T0), TA2 (T15:T8)
Command, Address Data
DS1977 sets Scratch-
DS1977 sets (E5:E0)
Master TX Data Byte
to Scratchpad Offset
pad Offset = (T5:T0)
Master RX CRC16 of
and Clears (PF, AA)
= Scratchpad Offset
Function Command
Master TX Memory
Master RX "1"s
pad Offset =
Scratchpad
TX Reset?
TX Reset?
TX Reset?
Master TX
Password?
Address of
Scratch-
N
Master
Master
Master
Write
3Fh?
0Fh
N
Y
N
N
Y
Y
Byte Written?
Y
N
Offset = (T5:T3,0,0,0) and
DS1977 sets Scratchpad
Partial
Clears (PF, AA, T2:T0)
Master TX one or both
8-byte passwords
N
11 of 29
From ROM Functions
Flow Chart (Figure 9)
PF = 1
Y
ments Scratch-
DS1977 Incre-
pad Offset
Flow Chart (Figure 9)
N
Y
To ROM Functions
E/S Byte, and Data Starting
Command, Address Data,
from Scratchpad Offset
DS1977 sets Scratch-
Master RX Data Byte
at the Target Address
pad Offset = (T5:T0)
Master RX CRC16 of
Master RX Ending
Offset with Data
Master RX "1"s
TA2 (T15:T8)
pad Offset =
TA1 (T7:T0)
Status (E/S)
Scratchpad
TX Reset?
TX Reset?
Master RX
Master RX
Scratch-
Master
Master
Read
3Fh?
AAh
N
Y
N
Y
N
Y
From Figure 7
To Figure 7
2
2
nd
nd
DS1977
Part
Part