Datasheet

DAC7678
www.ti.com SBAS493B –FEBRUARY 2010–REVISED JULY 2012
OPERATING EXAMPLES: DAC7678
For the following examples X = don’t care; value can be either '0' or '1'.
I
2
C Standard and Fast mode examples (ADDR0 and LDAC pin tied low) (TSSOP package)
Example 1: Write Mid Scale to Data Buffer A and Update Channel A Output
Command and
Start Address MSDB LSDB Stop
Access Byte
ACK ACK ACK ACK
S 1001 0000 0000 0000 1000 0000 0000 XXXX P
Channel A updates to Mid Scale after the falling edge of the last ACK cycle
SPACER
Example 2: Power-Down Channel B, C, and H with Hi-Z Output
Command and
Start Address MSDB LSDB Stop
Access Byte
ACK ACK ACK ACK
S 1001 0000 0100 XXXX X111 0000 110X XXXX P
SPACER
Example 3: Read-back the value of the input register of Channel G
Command and Repeated MSDB (from LSDB (from
Start Address Address
Access Byte Start DAC7678) DAC7678)
ACK ACK ACK ACK
S 1001 0000 0000 0110 Sr 1001 0001 XXXX XXXX XXXX 0000
SPACER
Example 4: Write multiple bytes of data to Channel F
Write Full Scale and then Quarter Scale to Channel F
Command and
Start Address MSDB LSDB MSDB LSDB Stop
Access Byte
ACK ACK ACK ACK* ACK ACK**
S 1001 0000 0000 0101 1111 1111 1111 XXXX 0100 0000 0000 XXXX P
Channel F updates to Full Scale after the falling edge of the 4th ACK* cycle and then Channel F updates to
quarter scale after falling edge of the last ACK** cycle.
I
2
C High Speed mode example (ADDR0 and LDAC pin tied low) (TSSOP package)
SPACER
Example 5: Write Mid Scale and then Full Scale to all DAC channels
HS Command
NOT Repeated
Start Master Address ACK and Access ACK MSDB ACK LSDB ACK MSDB ACK LSDB ACK Stop
ACK Start
Code Byte
S 0000 1000 Sr 1001 0000 0011 1111 1000 0000 0000 XXXX 1111 1111 1111 XXXX P
All Channels update to Mid Scale after the falling edge of the 4th ACK cycle and then all Channels update to Full
scale after falling edge of the last ACK cycle.
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