Part Number: ADS7138
Tool/software:
Hi Team,
My customer wants to config ADS7138 in auto-sequence mode, while they are not clear about how to send the conversion start frame and the conversion read frame, could you help to provide an example to demonstrate how the frame would look like?
Also, in auto sequence mode, which default register would device store the ADC data?
Regards,
Charles
Hi Charles,
The purpose of auto-sequence mode is to read the conversion directly on the I2C bus, rather than the extra overhead from reading the registers of the device through the I2C bus. When in auto-sequence, you also do not have to switch channels manually by programming the CHANNEL_SEL register.
The conversion start frame is just a standard I2C start condition, followed by the contents as described in figure 30 of the datasheet. The device keeps outputting data until the host provides a NACK condition.
It is useful to append the Channel ID bits to the conversion in order to keep track of what data corresponds to which channel.
The important thing to note is that reading conversion directly on the I2C bus is done with the host providing the device with a READ bit after providing the 7-bit device address, where the commands that use opcodes, seen in table 9 of the datasheet, need a WRITE bit to use.
Regards,
Joel
