The following table contains known issues, scheduled bug fixes, and feature improvements for the Iris Carrier Board.
For other information, click on the below links:
Description: The HSYNC and VSYNC input signals of the TH63LVD827 are swapped. The LCD_LCLK_A0 signal should be connected to the HSYNC input, and the LCD_FCLK_RD signal should be connected to the VSYNC. The LVDS interface is a transparent Link between the LVDS bridges. Therefore, the HSYNC and VSYNC are receiving the display also swapped. However, most displays ignore these signals. They solely use the data enable signal DE (LCD_BIAS) for synchronization.
Customer Impact: An assembly issue affecting an early production lot of the Iris V2.0A is causing a violation of a keepout zone defined for Colibri SoMs featuring an FFC connector on the bottom. These SoMs may not be properly inserted into the module connector of the affected carrier boards, potentially resulting in connection or reliability issues.
Description: An early production lot of the Iris V2.0A is affected by an assembly issue. The capacitor C133 (Figure 1) assembled is violating a keepout zone defined for Colibri SoMs featuring an FFC connector on the bottom. These SoMs may not be properly inserted into the module connector of the affected carrier boards, potentially resulting in connection or reliability issues. Please check the related errata document for more information.
Workaround: Removal of the capacitor C133 fully resolves the issue. Carrier board functionality is not impacted by the modification. C133 is not assembled on later production lots of the Iris V2.0A.
Customer Impact: The RTC circuit of a small percentage of Iris V1.1A carrier boards shipped before the 30th of October 2015 has an abnormal current consumption. This causes the RTC battery to be depleted faster than expected.
Description: The issue affects about 4% of the Iris V1.1A carrier boards shipped before the 30th of October 2015 and is caused by a broken capacitor (C55). It is possible to check the RTC circuit current consumption by measuring the voltage across a shunt resistor connected in series with the power supply used to provide 3.3V on the battery holder positive pin. The normal RTC standby supply current should be around 1uA.
Workaround: Customers who received products before the 30th of October 2015 and use the RTC circuit should measure the current consumption on already received products. If an abnormal current consumption is detected, contact the Toradex RMA department to get the board fixed or replaced. Our testing process has been adjusted to find the mentioned problem and rework the affected products.
Customer Impact: No negative impacts have been reported. There are no damages to the IO pins or the transceiver expected.
Description: The RS232 transceiver is backfeeding to the Iris carrier board and the module. For example, in combination with the Colibri iMX6 module, a residual voltage of around 0.7V can be measured at the 3.3V rail while only the RS232 cable is plugged in.
Workaround: Footprint compatible RS232 transceivers are available that do not backfeed. Replace IC4 and/or IC6 with one of the available options: TI TRS3243EIDBR TI MAX3243IDB ST ST3243EBTR
Customer Impact: No negative impacts have been reported. There are no damages to the module IO pin expected. The 560 Ohm resistor R115 limits the backfeeding current.
Description: If the USB client cable is plugged in while all other power sources are removed, the voltage divider circuit (R115/R116) on the USB_C_DET signal is backfeeding the module. For example, in combination with the Colibri iMX6 module, a residual voltage of around 0.85V can be measured at the 3.3V rail.
Workaround: Increase the resistor value of the divider. Change R115 to 5.6k (current value is 560R) and R116 to 10k (current value is 1k). According to tests with the Colibri iMX6, this reduces the residual voltage from 0.85V to 0.18V.
Customer Impact: Periodical enabling of the power rails and blinking of the LEDs.
Description: If only the USB client cable is plugged in while all other power sources are removed, the USB power switching IC1 gets enabled periodically. The enable input of the power switch IC is active low. If the power rails are removed, the USB_P_EN signal goes slowly down, which at one point enables the USB power switch. This unintentionally powers the board from the USB source through the 5V buck converter and turns on the 3.3V buck regulator. Since the 3.3V rail is up, the USB_P_EN signal also goes high and disables the USB power switch. This cycle repeats continuously and makes the power LEDs flashing.
Workaround: Assemble the resistor R157 instead of R156. This breaks the cycle since the cycle and the buck converters remain powered down. The backfeeding protection circuit inside the USB power switch (IC1) works and disables the switch regardless of the USB_P_EN signal level.
