© 2016 Integrated Device Technology, Inc.
3.2.5. High Level Protocol
The ZSC31010 will listen for a command/data pair to be transmitted for the 6 ms after the de-assertion of its
internal Power-On Reset (POR). If a transmission is not received within this time frame, then it will transition to
Normal Operation Mode (NOM). In NOM, it will output bridge data in 0 to 1 V analog, rail-to-rail ratiometric analog
output, or digital output, depending on how the part is currently configured.
If the ZSC31010 receives a Start CM command within the first 6 ms after the de-assertion of POR, then it will go
into Command Mode (CM). In this mode, calibration/configuration commands will be executed. The ZSC31010
will acknowledge successful execution of commands by transmission of an A5
H
. The calibrating/ configuring
master will know that a command was not successfully executed if no response is received after 130 ms of
issuing the command. Once in command interpreting/executing mode, the ZSC31010 will stay in this mode until
power is removed, or a Start NOM (Start Normal Operation Mode) command is received. The Start CM command
is used as an interlock mechanism, to prevent a spurious entry into command mode on power-up. The first
command received within the 6 ms window of POR must be a Start CM command to enter into command
interpreting mode. Any other commands will be ignored.
3.3. Command/Data Bytes Encoding
The 16-bit command/data stream sent to the ZSC31010 can be broken into 2 bytes, shown in Table 3.4. The
most significant byte encodes the command byte. The least significant byte represents the data byte.
Table 3.4 Command/Data Bytes Encoding
Command
Data
Description
00
H
XX
H
Read EEPROM command via Sig™ pin; for more details, refer to section 3.7.
20
H
5X
H
Enter Test Mode (subset of Command Mode for test purposes only): Sig™ pin will assume the
value of different internal test points depending on the most significant nibble of data sent.
DAC Ramp Test Mode. Gain_B[13:3] contains the starting point, and the increment is (Offset_B/8).
The increment will be added every 125 µsec.
30
H
dd
H
Trim/Configure: higher nibble of data byte determines what is trimmed/configured. Lower nibble is
data to be programmed. See Table 3.5 for configuration details of data byte dd
H
.
40H
00
H
Start NOM => Ends Command Mode, transition to Normal Operation Mode
10
H
Start Raw Mode (RM)
In this mode, if Gain_B = 800
H
and Gain_T = 80
H
, then the digital output will simply be the raw
values of the ADC for the Bridge reading and the PTAT conversion.
50
H
XX
H
Start_CM => Start the Command Mode; used to enter command interpret mode
60
H
dd
H
Program SOT (2
order term)
70
H
dd
H
Program T
SETL
80
H
dd
H
Program Gain_B, upper 7 bits (set MSB of dd
H
to 0
B
)
90
H
dd
H
Program Gain_B, lower 8 bits
A0
H
dd
H
Program Offset_B, upper 6 bits (set the two MSBs of dd
H
to 00
B
)
B0
H
dd
H
Program Offset_B, lower 8 bits
C0
H
dd
H
Program Gain_T
D0
H
dd
H
Program Offset_T
