SLAS986D November 2014 – February 2018 AMC7836
The AMC7836 device is controlled through a flexible four-wire serial interface that is compatible with SPI-type interfaces used on many microcontrollers and DSP controllers. The interface provides read and write (R/W) access to all registers of the AMC7836 device.
Each serial-interface access cycle is exactly (N + 2) bytes long, where N is the number of data bytes. Asserting the CS pin low initiates a frame. The frame ends when the CS pin is deasserted high. In MSB-first mode, the first bit transferred is the R/W bit. The next 15 bits are the register address (32768 addressable registers), and the remaining bits are data. For all writes, data is committed in bytes as the eight data bit of a data field that is clocked in on the rising edge of SCLK. If the write access is not an even multiple of 8 clocks, the trailing data bits are not committed. On a read access, data is clocked out on the falling edge of the serial interface clock, SCLK, on the SDO pin.
Streaming mode is supported for operations that require large amounts of data to be passed to or from the AMC7836. In streaming mode multiple bytes of data can be written to or read from the AMC7836 without specifically providing instructions for each byte. Streaming mode is implemented by continually holding the CS pin active and continuing to shift new data in or old data out of the device.
The instruction phase includes the starting address. The AMC7836 device begins reading or writing data to this address and continues as long as the CS pin is asserted and single byte writes have not been enabled in the interface configuration 1 register (address 0x01). The AMC7836 device automatically increments or decrements the address depending on the setting of the address ascension bit in the interface configuration 0 register (address 0x00).
If the address is decrementing and address 0x0000 is reached, the next address used is 0x7FFF. If the address is incrementing and address 0x7FFF is reached, the next address used is 0x0000. Care should be taken when writing to address 0x0000 and 0x0001 as writing to these addresses may change the configuration of the serial interface. Therefore address 0x0010 should be the first (ascending) or last (descending) address accessed in streaming mode.