ZSC31014EAC datasheet(34/58 Pages) IDT

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ZSC31014 Datasheet

January 20, 2016

3.2.1. I

2C™ Read_MR (Measurement Request)

The Read_MR (see example 1 in Figure 3.6) communication contains only the slave address and the READ bit

(1) sent by the master. After the ZSC31014 responds with the slave ACK, the master must create a stop

condition. This is only used in Sleep Mode (see section 3.1.2) to wake up the device and start a complete

measurement cycle (including the special measurements) followed by the DSP calculations and writing the results

to the digital output register.

Note: The I

2C™ Read_MR function can also be accomplished using the I2C™ Read_DF2 or Read_DF3

command and ignoring the “stale” data that will be returned.

3.2.2. I

2C™ Read_DF (Data Fetch)

For Data Fetch commands, the number of data bytes returned by the ZSC31014 is determined by when the

master sends the NACK and stop condition. For the Read_DF3 data fetch command (Data Fetch 3 Bytes;

see example 3 in Figure 3.6), the ZSC31014 returns three bytes in response to the master sending the slave

address and the READ bit (1): two bytes of bridge data with the two status bits as the MSBs and then 1 byte

of temperature data (8-bit accuracy). After receiving the required number of data bytes, the master sends the

NACK and stop condition to terminate the read operation.

For the Read_DF4 command, the master delays sending the NACK and continues reading an additional final byte

to acquire the full corrected 11-bit temperature measurement. In this case, the last 5 bits of the final byte of the

packet are undetermined and should be masked off in the application.

The Read_DF2 command is used if corrected temperature is not required. The master terminates the READ

operation after the two bytes of bridge data (see example 2 in Figure 3.6).

3.3. SPI Read Operations

The SPI interface of ZSC31014 can be programmed for falling-edge MISO change or rising-edge MISO change

(see SPI_Polarity, bit 0 of EEPROM word 02HEX, in section 3.6).

3.3.1. SPI Read_MR (Measurement Request)

A special SPI Read_MR command is used for waking up the part in Sleep Mode (see section 3.1.2). It performs a

measurement cycle including the special measurements and a correction calculation. The SPI Read_MR

command only requires that the SS line be dropped low for a minimum of 8µs then raised high again. The rise of

SS will trigger the part to power up and perform the measurements.

Figure 3.7

SPI Read_MR

Note: The SPI Read_MR function can also be accomplished using the SPI Read_DF command (refer to

section 3.3.2) and ignoring the “stale” data that will be returned.

8µs

ZSC31014EAC Datasheet(PDF) 34 Page - Integrated Device Technology