SBAS572B May 2013 – March 2019 ADS8864
The ADS8864 is a low pin-count device. However, the device offers six different options for interfacing with the digital host.
These options can be broadly classified as being either CS mode (in either a 3- or 4-wire interface) or daisy-chain mode. The device operates in CS mode if DIN is high at the CONVST rising edge. If DIN is low at the CONVST rising edge, or if DIN and CONVST are connected together, the device operates in daisy-chain mode. In both modes, the device can either operate with or without a busy indicator, where the busy indicator is a bit preceding the output data bits that can be used to interrupt the digital host and trigger the data transfer.
The 3-wire interface in CS mode is useful for applications that need galvanic isolation on-board. The 4-wire interface in CS mode allows the user to sample the analog input independent of the serial interface timing and, therefore, allows easier control of an individual device while having multiple, similar devices on-board. The daisy-chain mode is provided to hook multiple devices in a chain similar to a shift register and is useful in reducing component count and the number of signal traces on the board.