Help needed with getting Onkyo TS-SR875 8ch I2S/6 ch DSD input working/mod +other future mods an ideas
has anyone ever tryed modding the onkyo tx-sr875 using the 4X I2S PCM/DSD audio streams thats on the 10pin connector going from the notorious HDMI board NAHDM-9114 to the DSP board NADSP-9072 ?
there seems to be 2 main connectors a 10 pin to the DSP bord and a 15 pin connector going to the microprocessor board
the 10 pin connector has the following names for each connection in the service manual, then i have put in brackets what i think they stand for (also am i correctly naming them please ?)
1. HDSPDIR (i think this is the digital S/PDIF from the SIL9135 an also go's to SIL9134)
2. GNDHD Ground
3. PCMLR/DSDFL (I2S data for main Left & Right/DSD front Left
4. PCMBCK/DSDCLK (I2S/DSD Clock Signal)
5. PCMLRCK/DSDFR (I2S LR Clock/DSD front Right)
6. PCMCSW/DSDSW (I2S Center & Sub/DSD sub)
7. PCMSLR/DSDC (I2S Surround Left & Right/DSD Center)
8. PCMSBLR/DSDSR (I2S Surround Back Left & Right/DSD Surround Right)
9. GNDHD Ground
10. MCK_HDMI (Audio master clock ? - is this to help keep audio in sync with video pls ? could this be fed what ever signal it needs from say a gpio on a beagle board or something please and also used as is intended if i am right to keep video played from the likes of a BBB in sync with the I2S audio stream ?
also where is the DSDSL for the dsd audio Surround Left as i have copyed that fom the service manual ?
now hear comes where i do need as much help as possible please, is the 15 pin connector going from the hdmi Board to the microprocessing board and finding what signal's i need to recreate and how/if its possible from a gpio from something like a beagle bone black or another SBC that output's 4X I2S and also DSD audio streams in order to tick the microprocessor into thinking that the hdmi board is in fact fully functional and connected to something thats performed a successfully hdmi handshake with the sil9135 chip on the hdmi board and go ahead and process the I2S stream from the hdmi board going to the DSP's
Now some of the 15 pins are going to be related to the OSD as well as most of the 15 connections on the hdmi board seem to go to the MPD70F3716GC-8EA video microprocessor unit, but if the signal's are coming from a general microprocessor chip then im hoping that its possible to also use the gpio's on the beagle bone to recreate the appropriate data signals that tell's the main system processor that in fact a successfully hdmi handshake has taken place on what ever hdmi port number or make use of the Jtag and flashing connection's on the hdmi board for the MPD70F3716GC-8EA video microprocessor unit and possibly get it to just send out the appropriate data signals by possibly changing the code it run's if anyone has any ideas or experience with the programming of MPD70F3716GC-8EA chip's please
the 15 pin connector has the following named data lines
1. Ground
2. vsp rdy/vd clcok
3. vsp req/boot
4. " " "
5. tx mute (think this go's high to Mute the audio Out going to hdmi out ?)
6. hdmi sdo
7. hdmi clk
8. hdmi rst (go's high to reset the hdmi mpu ?)
9. vsp rst
10. CEC IO (CEC in/out data ?)
11. vsp rxd/vsp scl
12. vsp txd/ vsp sda
13. hdmi stb
14 rx mute (think this go's high to mute the audio I2S input stream i am trying to get working from hdmi board ?)
15. hdmi sdi
now can anyone help me please ? what signal's out of them 15 do i need to work out in order to get the I2S buses working please, any ideas ?
if only we could get the 4X I2S and DSD audio input bus's working the TX-SR875 would be one hell of a DIY project
it look's possible to mod the power supply's to,
the DAC board from separate highly regulated pure noise free power source along with analog input board
it seem's there's also 3 separate secondary winding's on the transformer for the power output stage but they each pass through a rectifying diode then coupled all all together but could split that up using extra filtering cap's then change how the powe output stage is powered, may be split it up like 2 of the winding's powering 2 channel's each then the other powering 3
the DSP board also has what i think is a JTag connection so may be possible to try and work with the 3 DSP chip's and re-program them as digital Xovers then you could use the amp as a 3 way stereo amp leaving a channel for sub making a basic 4 way with stereo top/mid/bass an shared mono sub channel's plus loads of other possibilities there for future development if only we can sort this I2S bus out first
as the Onkyo TX-SR875's with the HDMI problem are really cheap and a grate could be a really good DIY Gold Mine if its possible to activate the I2S and DSD bus coming from that hdmi board
ps, i have a raspi could i try to get the i2s bus working with that by any chance pls or is there any cheap usb to 4X i2s/6 ch dsd or anything thats really cheap and easy to get hold of here in the uk to start trying things out please ?
im also waiting for a single trace Oscilloscope i got cheap off ebay locally along with other stuff im slowly getting together for my new hobby, DIY Audio so expect to see knocking about on this forum more and moe as time go's on
please any help at all
thanks
has anyone ever tryed modding the onkyo tx-sr875 using the 4X I2S PCM/DSD audio streams thats on the 10pin connector going from the notorious HDMI board NAHDM-9114 to the DSP board NADSP-9072 ?
there seems to be 2 main connectors a 10 pin to the DSP bord and a 15 pin connector going to the microprocessor board
the 10 pin connector has the following names for each connection in the service manual, then i have put in brackets what i think they stand for (also am i correctly naming them please ?)
1. HDSPDIR (i think this is the digital S/PDIF from the SIL9135 an also go's to SIL9134)
2. GNDHD Ground
3. PCMLR/DSDFL (I2S data for main Left & Right/DSD front Left
4. PCMBCK/DSDCLK (I2S/DSD Clock Signal)
5. PCMLRCK/DSDFR (I2S LR Clock/DSD front Right)
6. PCMCSW/DSDSW (I2S Center & Sub/DSD sub)
7. PCMSLR/DSDC (I2S Surround Left & Right/DSD Center)
8. PCMSBLR/DSDSR (I2S Surround Back Left & Right/DSD Surround Right)
9. GNDHD Ground
10. MCK_HDMI (Audio master clock ? - is this to help keep audio in sync with video pls ? could this be fed what ever signal it needs from say a gpio on a beagle board or something please and also used as is intended if i am right to keep video played from the likes of a BBB in sync with the I2S audio stream ?
also where is the DSDSL for the dsd audio Surround Left as i have copyed that fom the service manual ?
now hear comes where i do need as much help as possible please, is the 15 pin connector going from the hdmi Board to the microprocessing board and finding what signal's i need to recreate and how/if its possible from a gpio from something like a beagle bone black or another SBC that output's 4X I2S and also DSD audio streams in order to tick the microprocessor into thinking that the hdmi board is in fact fully functional and connected to something thats performed a successfully hdmi handshake with the sil9135 chip on the hdmi board and go ahead and process the I2S stream from the hdmi board going to the DSP's
Now some of the 15 pins are going to be related to the OSD as well as most of the 15 connections on the hdmi board seem to go to the MPD70F3716GC-8EA video microprocessor unit, but if the signal's are coming from a general microprocessor chip then im hoping that its possible to also use the gpio's on the beagle bone to recreate the appropriate data signals that tell's the main system processor that in fact a successfully hdmi handshake has taken place on what ever hdmi port number or make use of the Jtag and flashing connection's on the hdmi board for the MPD70F3716GC-8EA video microprocessor unit and possibly get it to just send out the appropriate data signals by possibly changing the code it run's if anyone has any ideas or experience with the programming of MPD70F3716GC-8EA chip's please
the 15 pin connector has the following named data lines
1. Ground
2. vsp rdy/vd clcok
3. vsp req/boot
4. " " "
5. tx mute (think this go's high to Mute the audio Out going to hdmi out ?)
6. hdmi sdo
7. hdmi clk
8. hdmi rst (go's high to reset the hdmi mpu ?)
9. vsp rst
10. CEC IO (CEC in/out data ?)
11. vsp rxd/vsp scl
12. vsp txd/ vsp sda
13. hdmi stb
14 rx mute (think this go's high to mute the audio I2S input stream i am trying to get working from hdmi board ?)
15. hdmi sdi
now can anyone help me please ? what signal's out of them 15 do i need to work out in order to get the I2S buses working please, any ideas ?
if only we could get the 4X I2S and DSD audio input bus's working the TX-SR875 would be one hell of a DIY project
it look's possible to mod the power supply's to,
the DAC board from separate highly regulated pure noise free power source along with analog input board
it seem's there's also 3 separate secondary winding's on the transformer for the power output stage but they each pass through a rectifying diode then coupled all all together but could split that up using extra filtering cap's then change how the powe output stage is powered, may be split it up like 2 of the winding's powering 2 channel's each then the other powering 3
the DSP board also has what i think is a JTag connection so may be possible to try and work with the 3 DSP chip's and re-program them as digital Xovers then you could use the amp as a 3 way stereo amp leaving a channel for sub making a basic 4 way with stereo top/mid/bass an shared mono sub channel's plus loads of other possibilities there for future development if only we can sort this I2S bus out first
as the Onkyo TX-SR875's with the HDMI problem are really cheap and a grate could be a really good DIY Gold Mine if its possible to activate the I2S and DSD bus coming from that hdmi board
ps, i have a raspi could i try to get the i2s bus working with that by any chance pls or is there any cheap usb to 4X i2s/6 ch dsd or anything thats really cheap and easy to get hold of here in the uk to start trying things out please ?
im also waiting for a single trace Oscilloscope i got cheap off ebay locally along with other stuff im slowly getting together for my new hobby, DIY Audio so expect to see knocking about on this forum more and moe as time go's on
please any help at all
thanks