AnsweredAssumed Answered

Interface AD5790 evaluation board and RPi 3

Question asked by dasalam on Jul 6, 2017
Latest reply on Jul 13, 2017 by dasalam

Hello.

I would like to write my driver for control the AD5790 DAC with Raspberry Pi 3 (RPi).

 

I have an evaluation board (eval board) AD5790. The schematic is (see the photo below):

voltage from external power supply:

VDD = +11.67 V, AGND = to analog ground, VSS = -5.1 V

VCC = +5.15 V, DGND = to digital ground (also connected to RPi GND)

 

eval board pins | RPi pins (other pins does not use)

SYNC -> GPIO12 (I use it as chip select manually)

SCLK -> SPI_CLK

SDIN -> MOSI

SDO -> MISO

 

Links' config:

LK1 = B position

LK2 = B position

LK3 = A position

LK4 = removed

LK5 = removed

LK6 = removed

LK7 = inserted

LK8 = C position

LK9 = inserted

LK11 = inserted

 

I am using the following SPI configuration (I also tried many others):

mode: SPI MODE1

bit order: MSBFIRST

clock: 390.625kHz

 

In first I send "reset" command (0b 0100 0000 0000 0000 0000 01000) and then I send read control register command (0b 1010 0000 0000 0000 0000 0000). In last I send "readback" command through MOSI (0b 0000 ... 0000 i.e. all zeros) and try to read MISO, but the always result is 3 zero bits.

 

Could you help me? May be I did something wrong with hardware configuration or while programming.

 

schematic eval board ad5790 + Raspberry Pi 3

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