TCN75
4.3.1
ADDRESS BYTE
4.3.4
STOP CONDITION (STOP)
Immediately following the Start condition, the host must
next transmit the address byte to the TCN75. The four
Most Significant bits of the Address Byte (A6, A5, A4,
A3) are fixed to 1001(B). The states of A2, A1 and A0
in the serial bit stream must match the states of the A2,
A1 and A0 address inputs for the TCN75 to respond
with an Acknowledge (indicating the TCN75 is on the
bus and ready to accept data). The eighth bit in the
Address Byte is a Read/Write Bit. This bit is a ‘1’ for a
read operation or ‘0’ for a write operation.
Communications must be terminated by a Stop
condition (a LOW-to-HIGH transition of SDA while SCL
is HIGH). The Stop condition must be communicated
by the transmitter to the TCN75.
4.3.5
POWER SUPPLY
To minimize temperature measurement error, the
TCN75-3.3 MOA and TCN75-3.3 MUA are factory cal-
ibrated at a supply voltage of 3.3V ±5% and the
TCN75-5.0 MOA and TCN75-5.0 MUA are factory cal-
ibrated at a supply voltage of 5V ±5%. Either device is
fully operational over the power supply voltage range of
2.7V to 5.5V, but with a lower measurement accuracy.
The typical value of this power supply-related error is
±2°C.
4.3.2
ACKNOWLEDGE (ACK)
Acknowledge (ACK) provides a positive handshake
between the host and the TCN75. The host releases
SDA after transmitting eight bits then generates a ninth
clock cycle to allow the TCN75 to pull the SDA line
LOW to acknowledge that it successfully received the
previous eight bits of data or address.
4.3.3
DATA BYTE
After a successful ACK of the address byte, the host
must next transmit the data byte to be written or clock
out the data to be read. (See the appropriate timing
diagrams.) ACK will be generated after a successful
write of a data byte into the TCN75.
© 2006 Microchip Technology Inc.
DS21490C-page 9
MICROCHIP [ MICROCHIP ]
