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ADS1247EVM: ADS1247EVM connected to Beaglebone black.

Bill Pringlemeir
Prodigy 30 points

Part Number: ADS1247EVM

I have an ADS1247EVM connected to P9 of a beaglebone black. 

Name         P9    MUX    BBB Type    1248    EVM-J7    Linux
BBB_5V       6    5V    5V    5V    x    
nRESET      12    gpio_1_28    out    in    6    60
BBB_nRDY  16    gpio_1_19    in    out    9/15    51
BBB_nCS     28    spi1_cs0    spi    in    1    
BBB_DOUT    30    spi1_d1    spi    out   
BBB_SCLK    31    spi1_sclk    spi    in    3    
BBB_DIN       29    spi1_d0    spi    in    13    
BBB_START  15    gpio1_16    out    in    2    48

x

Channel 3 is the BBB SPI data and channel 1 is from the ADS1247 device.  What ever command I send, it seem to return a conversion result.  I can not write any registers and get back a response other than what seems to be a data conversion.  Reset, start toggling, etc do not effect.  If I leave start low, then only 0x00 is returned.  I can connect touch the AIN0, then the values change.  I think I have configured with the internal clock, but I didn't find a good place to probe that... it is internal and there is no test point for the CLK.

In the scope capture above, I sent '\x16\x00\x00\x00' from the BBB, but any value seems to give a data conversion with 'START' high.  IIRC, It gives a single conversion after start is low.  I guess that the i2c pins on J7 are related to the PDK and an ability to plug-in different boards.  I think I can ignore those J7 pins, esp. J7.12 which is an i2c voltage selection?  GND, 5V and 3.3V are connected from the BBB P9 as well.