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Hi all,
A friend and I are in the middle of designing a KVM switch for two computers to a single monitor using the HD3SS215 from Ti.
https://www.ti.com/product/HD3SS215/part-details/HD3SS215RTQR
We are confused as what to do with the Config 1 signal in displayport to HDMI converter applications as the datasheet doesnt really show what should be done with the signal.
Referring to the VESA Displayport interoperability standard, its very clear that the Config1 signal is low (below Vil) when a converter is connected and high (above Vih) when it is simply displayport to displayport. We are hoping to use the Config1 signal to detect the connection of a converter and switch the Aux_sel signal on the DP mux in order to switch the chip into HDMI DDC mode. We are hoping to do this without the use of a microcontroller.
What confuses me with the VESA standard is that Figure 5-1 is where I believe our KVM fits in this case (in between the Dual Mode Source and the Source Side Cable Adaptor. If this is the case then surely pin 13 (Config1) would be closer to 3V when a cable adapter is connected based simply on the resistor divider network that is completed upon connection (contrary to what the VESA standard would indicate for the signal).
We have built a prototype board and find that our board measure 0.7 V when a converter is connected, we have additional 1 MOhm resistors on the config line at each end but even then we should be seeing 2.5 V on the line if the diagram in 5-1 is to be believed.
Can anyone that has experience with displayport to hdmi/DVI conversion give us a hand in explaining what Config1 actually does and how it works????
Thanks so much in advance and I can provide schematics of our test board and such if needed.
A friend and I are in the middle of designing a KVM switch for two computers to a single monitor using the HD3SS215 from Ti.
https://www.ti.com/product/HD3SS215/part-details/HD3SS215RTQR
We are confused as what to do with the Config 1 signal in displayport to HDMI converter applications as the datasheet doesnt really show what should be done with the signal.
Referring to the VESA Displayport interoperability standard, its very clear that the Config1 signal is low (below Vil) when a converter is connected and high (above Vih) when it is simply displayport to displayport. We are hoping to use the Config1 signal to detect the connection of a converter and switch the Aux_sel signal on the DP mux in order to switch the chip into HDMI DDC mode. We are hoping to do this without the use of a microcontroller.
What confuses me with the VESA standard is that Figure 5-1 is where I believe our KVM fits in this case (in between the Dual Mode Source and the Source Side Cable Adaptor. If this is the case then surely pin 13 (Config1) would be closer to 3V when a cable adapter is connected based simply on the resistor divider network that is completed upon connection (contrary to what the VESA standard would indicate for the signal).
We have built a prototype board and find that our board measure 0.7 V when a converter is connected, we have additional 1 MOhm resistors on the config line at each end but even then we should be seeing 2.5 V on the line if the diagram in 5-1 is to be believed.
Can anyone that has experience with displayport to hdmi/DVI conversion give us a hand in explaining what Config1 actually does and how it works????
Thanks so much in advance and I can provide schematics of our test board and such if needed.
