Datasheet

DS1921H/Z
18 of 45
MEMORY/CONTROL FUNCTION FLOW CHART Figure 10-1
Master TX Memory or
Control Fkt. Command
0FH
Write
Scratchpad
DS1921 sets Scratch-
pad Offset = (T4:T0)
and Clears (PF, AA)
Master TX Data Byte
to Scratchpad Offset
DS1921 sets (E4:E0)
= Scratchpad Offset
Master
TX Reset?
Scratch-
pad Offset =
11111b?
Master RX CRC16 of
Command, Address, Data
DS1921 Incre-
ments Scratch-
pad Offset
Master RX "1"s
Master
TX Reset?
Master
TX Reset?
Partial
Byte Written?
PF = 1
AAH
Read
Scratchpad
Master RX Ending
Offset with Data
Status (E/S)
Master
TX Reset?
Scratch-
pad Offset =
11111b?
Master RX CRC16 of
Command, Address Data,
E/S Byte, and Data Starting
at the Target Address
DS1921 Incre-
ments Scratch-
pad Offset
Master RX "1"s
Master
TX Reset?
DS1921 sets Scratch-
pad Offset = (T4:T0)
Master RX Data Byte
from Scratchpad Offset
From ROM Functions
Flow Chart (Figure 12)
To ROM Functions
Flow Chart (Figure 12)
N
Y
N
Y
N
Y
N
Y
N
Y
N
Y
Y
N
Y
N
Y
N
Y
DS1921 sets
EMCLR = 0
Master TX
TA1 (T7:T0), TA2 (T15:T8)
DS1921 sets
EMCLR = 0
Master RX
TA1 (T7:T0), TA2 (T15:T8)
To Figure 10
2
nd
Part
N
From Figure 10
2
nd
Part