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5.2 Temperature Transmission Packet from a TSic
The TSic transmits 1-byte packets. These packets consist of a start bit, 8 data bits, and a parity bit. The nominal baud
rate is 8 kHz (125 µsec bit window). The signal is normally high. When a transmission occurs, the start bit occurs first
followed by the data bits (MSB first, LSB last). The packet ends with an even parity bit.
Figure 1.1 – ZACwire
The TSic provides temperature data with 11-bit or 14-bit resolution, and obviously these 11 bits or 14-bit of infor-
mation cannot be conveyed in a single packet. A complete temperature transmission from the TSic consists of two
packets. The first packet contains the most significant 3 bits or 6 bits of temperature information, and the second
packet contains the least significant 8 bits of temperature information. There is a single bit window of high signal
(stop bit) between the end of the first transmission and the start of the second transmission.
Figure 1.2 – Full ZACwire
5.3 Bit Encoding
The bit format is duty cycle encoded:
Start bit =>
Logic 1 =>
Logic 0 =>
Perhaps the best way to show the bit encoding is with an oscilloscope trace of a ZACwire
wing shows a single packet of 96 Hex being transmitted. Because 96 Hex is already even parity, the parity bit is zero.
ATTSic_E2.1.4 | App Note | Temperature Sensor IC
Transmission Packet
TM
For 14-bit res.
Temperature Transmission from TSic
TM
50 % duty cycle used to set up strobe time
75 % duty cycle
25 % duty cycle
TM
transmission. The follo-
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