About the AD7380/16bit SDOA data no signal output problem

Question

Hello, 
 MCU: TI-28379D 
 ADC driver: AD4940, The input signal used the single-end to convert full differentiation data. 
 Gain 0.65 
 VCM:1.65v 
 V-ref: 3.3v 
 V-logic : 3.3v 
 Vs+ : 5v 
 Vs- : 0v 
 I checked the SPI signal level measurement from MCU to AD7380 is fine. 
 But I don't understand the SDOA why the signal is not output. 
 How to verify AD7380 communication is works? 
 (SCK/SDIO signal data MCU to AD7380) 
 
 (SCK/SDOA no signal output, still lower level)

jcolao · Accepted Answer

Hi Steven, 
 
 Apologies for this confusion. Regarding the ALERT_LOW and ALERT_HIGH thresholds. The default values are set at 0x800 and 0x7FF. These default values are MSBs, the remaining 4 LSBs as mentioned briefly in the second sentence of the description are 0x0 for Alert low threshold and 0xF for the high threshold that completes the total to 16 bits. 
 
 Regards, 
 Jonathan

jcolao · Answer

Hi Steven, 
 It is good that you are now seeing the SDOA. 
 Just a clarification, the readback is from what register? Register 0x1, 0x2 and 0x3 are default value at 0. While 0x4 and 0x5 have 0x0800 and 0x07FF respectively. What are these data, 0x0000,0x2000,0xA1FFF,02000? are these conversion results. based on what you mentioned, all registers from the AD7380 are set at default. Is this correct? If you can try writing to the part and perform readback would be a good test. 
 Regards, 
 Jonathan

Electronic Design Services - PartnerZone

Products In This Thread

About the AD7380/16bit SDOA data no signal output problem

Top Replies