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S4GX530 dev kit; HDMI audio not working

Honored Contributor II

Hi All, 


I am using the AD9889B chip on the Startix 4 GX 530 dev kit. I am trying to get the audio up and running but unfortunately without any success. 




I have a 480p video test pattern output (running on a 27MHz pixel clock). The HDMI video is working fine. 

For the audio : 48kHz Stereo, SCLK=3.072MHz, LRCLK=48kHz, MCLK=12.288MHz. 

(I create these clocks with a PLL in the FPGA from the 27MHz video clock, so an integer relationship exists) 

I pad the 16 bit audio data with zeroes to form 32 bit words. The 16 bit audio data that I would like to hear is a saw-tooth of about 100 Hz. 


I set the following registers : 

wr 0x96 <- 0x00 --clear interupts 

wr 0x41 <- 0x50 --power down chip 

rd 0x42 -> 0xE0 

wr 0x17 <- 0x18 --csc 

wr 0x3b <- 0x01 --enable csc 

wr 0x15 <- 0x20 --48kHz audio; YCbCr 4:4:4 input 

wr 0x16 <- 0x01 --output = YCbCr 

wr 0x0C <- 0x04 --enable I2S(0), I2S format=standard (I am using 32bit per sample here, 2x32 for 1 stereo sample) 

wr 0x50 <- 0x20 --enable 2 audio channels 

wr 0x14 <- 0x02 --16 bit word length 

wr 0x0A <- 0x01 --select I2S, Mclk inactive, Mclk ratio : 256xFs 

wr 0x40 <- 0xF8 -- 

wr 0x44 <- 0x78 

wr 0x45 <- 0x80 --AV mute disable, output format RGB 

wr 0x94 <- 0xF0 -- 

wr 0x95 <- 0x00 -- 

wr 0x96 <- 0x40 -- 

wr 0x97 <- 0x00 -- 

wr 0x98 <- 0x07 -- 

wr 0x9C <- 0x38 -- 

wr 0x9D <- 0x60 -- 

wr 0xBB <- 0xFF -- 

wr 0x01 <- 0x00 --N = 6144 

wr 0x02 <- 0x18 

wr 0x03 <- 0x00 

wr 0xAF<- 0x16 --HDMI mode 

wr 0x41 <- 0x10 --power up chip 


I have been checking and re-checking my register settings + general setup but can not figure out where I am going wrong. 


Could anybody please help? 


In Advance thx for your help
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Honored Contributor II

Hi Nik83, 


For some reason I can not reply to your PM. 


So here is my reply 


Hi Nik83, 


I do not have a SOPC-system. I just made a little testproject where I generate a video source in VHDL + a I2C connection towards the AD9889B. 



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