When using a PD controller to configure a TUSB1044 (Type-C Linear Redriver) over I2C it is best to follow the scheme below for programming the PD in this regard. This scheme also includes support for applications in need of a "virtual" HPD.
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// Register configurations written as follows: (addr, data)
// Example assumes following:
// Alt DP Mode Source with SWAP = 0; DIR0 = 0; DIR1 = 1;
// USB EQ downstream direction: UTX1EQ_SEL = 5 and UTX2EQ_SEL = 5
// USB EQ upstream direction: DRX1EQ_SEL = 2 and DRX2EQ_SEL = 2
// DP EQ: 6
// Initialize EQ each receiver.
(0x0A, 0x10) // Make sure EQ_OVERRIDE is set.
(0x10, 0x56) // UEQ2
(0x11, 0x56) // UEQ1
(0x20, 0x22) // DEQ2 for TypeC Rx2 port.
(0x21, 0x22) // DEQ1 for TypeC Rx1 Port
If USB-only normal orientation
{
(0x11, 0x56) // Set UEQ for UTX1
(0x0A, 0x11)
}
else if USB-only flip orientation
{
(0x10, 0x56) // Set UEQ for UTX2
(0x0A, 0x15)
}
Else if DP-only normal orientation
{
(0x10, 0x66) // UEQ2
(0x11, 0x66) // UEQ1
(0x0A, 0x12)
}
Else if DP-only flip orientation
{
(0x10, 0x66) // UEQ2
(0x11, 0x66) // UEQ1
(0x0A, 0x16)
}
Else if DP+USB normal orientation
{
(0x10, 0x66) // Set DP EQ
(0x11, 0x56) // Set USB EQ
(0x0A, 0x13)
}
Else if DP+USB flip orientation
{
(0x10, 0x56) // Set USB EQ
(0x11, 0x66) // Set DP EQ
(0x0A, 0x17)
}
Else nothing connected to Type-C
{
(0x0A, 0x10)
(0x10, 0x56) // UEQ2
(0x11, 0x56) // UEQ1
}
//For using virtual HPD support.
// HPDIN pin assumed to be low.
If (DP Alt mode)
{
If (HPD = removal)
{
HPDIN_OVERRIDE = 0;
}
Else //HPD insertion or IRQ_HPD
{
HPDIN_OVERRIDE = 1;
}
}