Texas Instruments ADS1259EVM, Руководство пользователя

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ADS1259 Control
6 ADS1259 Control
The ADS1259 can be used as a standalone device on the EVM or can be controlled using the interface
with the PGA280. However, to use the ADS1259EVM-PDK with the ADCPro software, the PGA280 must
be used as the control for the ADS1259.
To operate the ADS1259 without the PGA280, all the jumpers from J2, J3, and J4 should be moved to the
right, connecting pins 2 and 3 of each jumper. These jumpers connect the ADS1259 to the EVM serial
interface header and allow control of the ADS1259 CS, START, and RST/PDWN pins through J7.
Communications with the ADS1259 are handled with an SPI™-compatible serial interface. From the serial
interface header, SCLK is handled with CLKX, chip select is handled by FSX, DIN comes from DX, DOUT
goes to DR, and DRDY goes to INT. Additionally, the START pin (used to start a conversion) is run from
GPIO0; reset and the power-down pin can be controlled by GPIO1.
The ADS1259 can also be controlled through communications from the PGA280. The PGA280 can
generate an extended chip select (ECS) for other devices that are connected to the same SPI wires: SDO,
SDI, and SCLK. This ECS signal redirects the SPI communication to the connected device, while the
PGA280 ignores data and SCLK. For this type of control, all the jumpers from J2, J3, and J4 should be
moved to the left, connecting pins 1 and 2 of each jumper. This configuration connects the PGA280 to the
ADS1259 though several of the PGA GPIOs. Note that this method of control is used in the
ADS1259EVM-PDK, and that jumpers J2, J3, and J4 must be set to the left to enable control through
ADCPro and the ADS1259EVM plug-in.
PGA280:GPIO0-2 can be used to control external functions, such as a mux.
PGA280:GPIO3 can be used to enable a reset or power-down of the ADS1259.
PGA280:GPIO4 can be used to toggle the START pin of the ADS1259 to trigger a conversion.
PGA280:GPIO5 is used to generate chip select (ECS) for the ADS1259.
PGA280:GPIO6 receives the ACLKOUT signal from the ADS1259. This port sends out an f
S
/8 clock from
the ADS1259 that can be used as a synchronized chopper clock for the PGA280. Note that this
configuration requires J1 to be set so that pins 2 and 3 are connected.
For more details, see the PGA280 data sheet .
7 Clock Source
The ADS1259 clock can come from one of several sources. It can be selected through switch S4, as
illustrated in
Figure 6 .
Figure 6. Switch S4
• A crystal dropped into X1 with switch S4 set to the unconnected setting to the right.
• The ADS1259 can start an internal oscillator upon power up with switch S4 switched to ground to the
center.
• The crystal oscillator (U32) can be selected through GPIO5 HIGH and switch S4 set to the left,
selecting the multiplexer (U31) output.
• A TOUT clock coming from the serial header (J7.17) can be selected through GPIO5 LOW, with switch
S4 selecting the multiplexer (U31)
9 SBAU163A – March 2010 – Revised April 2010 ADS1259EVM, ADS1259EVM-PDK
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