Information

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ZACWIRE
TM
DIGITAL OUTPUT
1 TSic
TM
ZACwire™ Communication Protocol
ZACwire™ is a single wire bi-directional communication protocol. The bit encoding is
similar to Manchester in that clocking information is embedded into the signal (falling
edges of the signal happen at regular periods). This allows the protocol to be largely
insensitive to baud rate differences between the two ICs communicating.
In end-user applications. the TSic
TM
will be transmitting temperature information, and
another IC in the system (most likely a Controller) will be reading the temperature
data over the ZACwire™.
1.1 Temperature Transmission Packet from a TSic
TM
The TSic
TM
transmits 1-byte packets. These packets consist of a start bit, 8 data bits,
and a parity bit. The nominal baud rate is 8kHz (125microsec 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.
The TSic
TM
provides temperature data with 11-bit resolution, and obviously these 11-
bits of information cannot be conveyed in a single packet. A complete temperature
transmission from the TSic
TM
consists of two packets. The first packet contains the
most significant 3-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.