AD2S1200/05SDZ Eval SPI interface

Question

I'm trying to read Resolver data from the EVAL-AD2S1200/05SDZ board over SPI. 
 My on-board jumper settings: 
 LK1 - A LK2 - A LK3 - A LK4 - A LK6 - B LK5 - Not inserted (10kHz) LK7,LK8 - C LK501 - A LK701 - A LK702 - A 
 The evaluation board seems to be working fine, no error LEDs are lit and DIR and A/B LEDs work correctly depending on how the Resolver is spun. 
 J4 connection: 
 RD - CS (MCU) SCLK - SCLK (MCU) SO - MISO (MCU) DGND - GND ref to (MCU) SAMPLE - GND DVDD - NC CS - GND RDVEL - VDD 
 However, I'm having trouble reading data over SPI. I'm using a SCLK frequency of 330kHz. 
 Here's a screenshot of the logic analyzer during an attempted read: 
 
 I assume my J4 connections might be incorrect. I was hoping I would only need 3 pins between the AD2S1205 and my MCU. 
 Thanks for any input.

andreialejandro · Accepted Answer

Hi, 
 I noticed that in your SPI lines, the sample input pin is directly connected to GND in which is not recommended because the data is transferred from the position and velocity integrators, respectively, to the position and velocity registers following a high-to-low transition on the SAMPLE signal. This pin must be held low for at least t1 ns to guarantee the correct latching of the data. I recommend connecting the SAMPLE input pin signal to the reserved digital IO pins of the MCU and control this pin based on the timing specifications of the RDC. 
 Regards, 
 Andrei)

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AD2S1200/05SDZ Eval SPI interface