Rainbow Electronics DS1721 - Manual (Page 13)

DS1721
13 of 16
SAMPLE COMMAND SEQUENCE Table 6
Example: Bus master programs the DS1721 for 11-bit conversions in the continuous mode with an active
low state for the thermostat output. It then programs TH=50°C and TL=45°C and starts temperature
conversions.
BUS MASTER
MODE
DS1721
MODE
DATA (MSB
FIRST)
COMMENTS
TX RX START Bus Master initiates a START condition
TX RX <address, 0> Bus Master sends DS1721 address; R/ W = 0
RX TX ACK DS1721 generates acknowledge bit
TX RX ACh Bus Master sends access configuration protocol
RX TX ACK DS1721 generates acknowledge bit
TX RX 08h Bus Master programs configuration register as
described above. This will also clear thermostat
flags
RX TX ACK DS1721 generates acknowledge bit
TX RX START Bus Master Initiates a REPEATED START
condition
TX RX <address, 0> Bus Master sends DS1721 address; R/ W = 0
RX TX ACK DS1721 generates acknowledge bit
TX RX A1h Bus Master sends access TH protocol
RX TX ACK DS1721 generates acknowledge bit
TX RX 32h Bus Master writes MSB of TH (50°C)
RX TX ACK DS1721 generates acknowledge bit
TX RX 00h Bus Master writes LSB of TH (50°C)
RX TX ACK DS1721 generates acknowledge bit
TX RX START Bus Master initiates a REPEATED START
condition
TX RX <address, 0> Bus Master sends DS1721 address; R/ W = 0
RX TX ACK DS1721 generates acknowledge bit
TX RX A2h Bus Master sends access TL protocol
RX TX ACK DS1721 generates acknowledge bit
TX RX 2Dh Bus Master writes MSB of TL (45°C)
RX TX ACK DS1721 generates acknowledge bit
TX RX 00h Bus Master writes LSB of TL (45°C)
RX TX ACK DS1721 generates acknowledge bit
TX RX START Bus Master initiates a REPEATED START
condition
TX RX <address, 0> Bus Master sends DS1721 address; R/ W = 0
RX TX ACK DS1721 generates acknowledge bit
TX RX 51h Bus Master sends start convert protocol
RX TX ACK DS1721 generates acknowledge bit
TX RX STOP Bus Master initiates STOP condition