Datasheet
Table Of Contents
- Content Guide
- 1 General Description
- 2 Ordering Information
- 3 Pin Assignment
- 4 Absolute Maximum Ratings
- 5 Operating Conditions
- 6 Register Description
- 6.1 Register Overview
- 6.2 Detailed Register Description
- 6.3 Serial Interface
- 6.3.1 Bus Description
- 6.3.2 Data Interface
- 6.3.3 Bus Address
- 6.3.4 Read/Write Operation
- 6.3.5 Slave Operation
- 6.3.6 Slave Receiver Mode
- 6.3.7 Slave Transmitter
- 6.3.8 Alert Function
- 6.3.9 High Speed Mode
- 6.3.10 General Call
- 6.3.11 Start Byte
- 6.3.12 Timeout Function
- 6.3.13 Bus Conditions
- 6.3.14 Timing Characteristics
- 6.3.15 Timing Diagrams
- 7 Application Information
- 8 Package Drawings & Markings
- 9 Revision Information
- 10 Legal Information
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AS621x
Register Description
Datasheet • PUBLIC
DS000677 • v2-00 • 2020-Feb-24
36 │ 26
Figure 29:
Alert Condition Bit
Polarity Bit
Alert Condition
Alert Condition Bit (AC-Bit)
0
T ≥ THIGH
0
0
T ≤ TLOW
1
1
T ≥ THIGH
1
1
T ≤ TLOW
0
6.3.9 High Speed Mode
The bus operation is limited to 400kHz unless a high speed command is issued by the master device
as the first byte after a START condition. This switches the bus to a high speed operation which allows
data transfer frequencies up to 3.4MHz. Such a command is not acknowledged by the slave but the
input filter time constants on the serial interface (SDA and SCL) are adapted to allow the higher
transfer rate.
After a high speed command, the slave address is transmitted by the master in order to invoke a data
transfer. The bus keeps operating at the higher operating frequency until the master issues a STOP
condition on the serial bus. Upon the reception of the STOP condition by the slave, the input filters are
switched to their initial time constants which allow lower transfer rates only.
6.3.10 General Call
A general call is issued by the master by transmitting the general call address (000 0000) with a low
R/W bit. When this command is issued on the bus, the device acknowledges this command. The
device also acknowledges the second byte but ignores the data. Subsequent bytes sent by the master
during the general call are not acknowledged.
6.3.11 Start Byte
When the master transmits address 000 0000 and a high R/W bit (“START byte”) the device
acknowledges the address. The device then send the MSB data byte and LSB data byte, where the
data corresponds to the content of the register whose address has been last written to. After reset this
corresponds to the temperature register.
6.3.12 Timeout Function
The serial interface of the slave device is reset if the clock signal SCL is kept low for typ. 30ms. Such
a condition results in a release of the data line by the slave in case it has been pulled to low level. The
slave remains inactive after a timeout and waits for a new START command invoked by the bus
master. In order to prevent a timeout, the bus transfer rate must be higher than 1kHz.