Table 5. example input word – Rainbow Electronics MAX550A User Manual
Page 12
MAX548A/MAX549A/MAX550A
+2.5V to +5.5V, Low-Power, Single/Dual,
8-Bit Voltage-Output DACs in µMAX Package
12
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Table 4. MAX550A Serial-Interface Programming Commands
COMMANDS LOADING DAC REGISTER
COMMANDS LOADING INPUT REGISTER ONLY
UNASSIGNED COMMANDS
Loaded Last
Loaded First
LDAC
CONTROL BYTE
COMMAND
(Commands executed on
CS
’s rising edge)
X
Update DAC register with current contents of
input register. Input register unchanged.
0
0
X
1
1
X
0
X
XXXXXXXX
X
Load DAC input register and update DAC register.
0
8-Bit DAC Data
1
X
1
1
X
0
X
XXXXXXXX
X
Load DAC input register and update DAC register.
X
8-Bit DAC Data
1
X
0
1
X
0
X
UB1
Pin 6
D7........D0
A0
A1
C0
C1
UB3
C2
UB2
X
Update DAC register with current contents of
input register. Input register unchanged.
X
0
X
0
1
X
0
X
X
Load DAC input register. DAC register unchanged.
X
8-Bit DAC Data
1
X
X
0
X
0
X
X
Unassigned operation
X
XXXXXXXX
0
X
X
X
X
X
1
X
Unassigned command
X
XXXXXXXX
0
X
X
0
X
0
X
DATA BYTE
COMMANDS UTILIZING THE ASYNCHRONOUS LOAD FUNCTION
X
After CS’s rising edge and on LDAC’s falling
edge, update DAC register with current contents
of input register. Input register unchanged.
1
XXXXXXXX
0
X
1
1
X
0
X
X
Load DAC input register. After CS’s rising edge
and on LDAC’s falling edge, update DAC register.
1
8-Bit DAC Data
1
X
1
1
X
0
X
COMMAND POWERING DOWN AND LOADING INPUT REGISTER ONLY
X
Load DAC input register and power down DAC.
X
8-Bit DAC Data
1
X
X
0
X
1
X
COMMANDS POWERING DOWN AND UPDATING DAC REGISTER
X
Load DAC input register, power down DAC, and
update DAC register.
X
8-Bit DAC Data
1
X
0
1
X
1
X
X
Load DAC input register, power down DAC, and
update DAC register.
0
8-Bit DAC Data
1
X
1
1
X
1
X
COMMAND POWERING DOWN AND UTILIZING THE ASYNCHRONOUS LOAD FUNCTION
X
Load DAC input register and power down DAC.
While powered down, on LDAC’s falling edge,
update DAC register.
1
8-Bit DAC Data
1
X
1
1
X
1
X
Table 5. Example Input Word
X = Don’t care
X = Don’t care
UB2
X
C2
0
UB3
X
C0
0
CONTROL BYTE
A0
1
Loaded First
A1
0
C1
1
D6
0
D4
0
D5
0
D2
0
DATA BYTE
D0
0
Loaded Last
D1
0
D3
0
D7
1
UB1
X