We have a design with a TUSB8043A connected directly to the CPU USB lines (with bypass caps on the TX/RX lines), but are having issues enumerating the device.
Other USBs are detected on the CPU, so it's limited to just this hub. Here's a couple of things we have tested:
- confirmed the GRSTZ is low during power up of 1V1 and both 1V1 and 3V3 reach their proper voltages
- confirmed oscillator outputs 24MHz
- vbus is ~450-500mV but always powered via onboard 5V
- CPU_TX connects to Hub_RX and CPU_RX connects to Hub_TX
- No errors reported by Linux or U-Boot on the USB lines
- SCL/SDA and PWRCTL_POL floating
- SMBUSz, FULLPWRMGMTz, GANGED, AUTOENz, and TEST low
- USB_R1 tied to GND with 9.53k resistor
Any ideas on where to start with this device?
