AMC7836_15 Datasheet, PDF (42/87 Pages) Texas Instruments – AMC7836 High-Density, 12-Bit Analog Monitor and Control Solution With Multichannel ADC, Bipolar DACs, Temperature Sensor, and GPIO Ports

AMC7836
SLAS986B – NOVEMBER 2014 – REVISED FEBRUARY 2015
www.ti.com
7.5 Programming
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.
Figure 60 and Figure 61 show the access protocol used by the interface.
CS
SCLK
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
SDI R/W A14 A13 A12 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0 D7 D6 D5 D4 D3 D2 D1 D0
SDO
Figure 60. Serial Interface Write Bus Cycle
CS
SCLK
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
SDI
R/W A14 A13 A12 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0
SDO
D7 D6 D5 D4 D3 D2 D1 D0
Figure 61. Serial Interface Read Bus Cycle
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.
Figure 62 and Figure 63 show the access protocol used in streaming mode.
42
Submit Documentation Feedback
Product Folder Links: AMC7836
Copyright © 2014–2015, Texas Instruments Incorporated