| Sl # |
Issue/Caveat |
Description |
Workaround |
Comments |
| 1 |
OTG Port, VBUS Fault Detection Feature |
The VBUS Fault detection input of ISP1507 (U36) on the EVM Main board can be connected to two sources with resistor installation options.
1. Resistor R830 connects the Fault detection input to the Over Current detection output of an OTG VBUS switch.
2. Resistor R845 connects the Fault detection input to ground to disable the ISP1507 Fault feature when not used (Same as REV-D & E Main board).
Currently, the EVM main board has both optional resistors installed on the Main board which disables the Fault detection input feature of the ISP1507, and disables the fault input to U152. |
The Fault detection feature does not have a functional impact on the OTG port if the USE_EXT_VBUS_IND bit in the ISP1507 is set low. This feature is currently disabled on the main board, like previous EVM platforms. There is a board level work around to enable this feature. Refer to the PDF on the ECN layout,
Section 1 - HSUSB-OTG VBUS Fault Detection Feature, for implementation details. |
Applicable to EVM MAIN BOARD REVG. |
| 2 |
OTG Port, VBUS Decoupling Capacitor option |
The current design allows the VBUS power source on the USB OTG port to be switched between standard host (500mA) and OTG mode. The default is standard host mode which is capable of sourcing 500mA of current. A 100uF (C552) decoupling capacitor is connected to VBUS. The USB specification requires a 120uF or greater capacitor connected to VBUS when operating in standard host mode and the USB OTG specification requires the VBUS capacitance to be in the range of 1 - 6.5uF for OTG mode. The board should have been designed with a 4.7uF capacitor connected to VBUS with a jumper option that allows an additional 120uF to be connected to VBUS when operating in standard host mode. |
It may be necessary to replace the 100uF capacitor installed in location C552 with a 120uF capacitor if the voltage on VBUS drops below the specified level when a USB device is attached when operating in standard host mode. It may be necessary to replace the 100uF capacitor installed in location C552 with a 4.7uF capacitor if operating in OTG mode. Refer to the PDF on the ECN layout,
Section 2a & 2b HSUSB-OTG VBUS Capacitor - OTG/Host Mode, for implementation details |
Applicable to EVM MAIN BOARD REVG. |
| 3 |
Host Port, VBUS Decoupling Capacitor |
A 100uF (C445) decoupling capacitor is connected to VBUS. The USB specification requires a 120uF or greater capacitor connected to VBUS when operating in standard host mode. The board should have been designed with a 120uF or Higher Value capacitor connected to VBUS. |
It may be necessary to replace the 100uF capacitor installed in location C445 with a 120uF or greater capacitor if the voltage on VBUS drops below the specified level when a USB device is attached when operating in standard host mode. Refer to the PDF on the ECN layout,
Section 3. Host Port, VBUS Decoupling Capacitor |
Applicable to OMAP EVM MAIN BOARD REVB only.
This has been Fixed in OMAP EVM MAIN BOARD REVC & above. |
| 4 |
HSUSB HOST INTERFACE ID-Pin for A-devices |
In the current design ID pin of USB3320C-EZK is grounded through 10K, but for A-devices, ID pin has to grounded through 0ohm Resistor. |
For supporting A-Devices, install 0ohm at resistor R639 instead 10Kohm. Refer to the PDF on the ECN layout, Section 4. HSUSB-HOST ID pin for A-devices, for implementation details |
Applicable to EVM MAIN BOARD REVG. |
| 5 |
LOW POWER MODE of EVM |
In normal mode, SYS_CLKREQ is high. In low power mode, SYS_CLKREQ goes to high impedance. But In the current design SYS_CLKREQ is pulled high and this keeps it high, and so the PMIC never shuts down voltages in OFF mode. |
If Low power mode needs to be supported on this board, the resistor at R24 could be removed. Refer to the PDF on the ECN layout, Section 5. LOW POWER MODE of EVM, for implementation details. |
Applicable to EVM POWER MODULE REVD. |
