Iris Carrier Board

Customer Impact: LVDS displays connected to the LVDS connector (X7) of the carrier board may not function (not show any picture and remain black) in case they require the HSYNC and VSYNC signals for synchronization. LVDS displays not requiring those signals are not impacted.

Description: Most LVDS displays don't rely on the HSYNC and VSYNC signals for synchronization, they use the data enable signal DE (LCD_BIAS) instead. However, there are some LVDS displays that require the HSYNC and VSYNC signals for proper operation. Unfortunately, it is oftentimes not clearly indicated in the displays' datasheets whether the HSYNC and VSYNC signals are required. In the Ixora V2.0, the HSYNC and VSYNC input signals of the TH63LVD827 bridge 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 input). As the LVDS link is transparent between the LVDS bridges (on the carrier board's and the display's side), the HSYNC and VSYNC signals are also swapped on the display's side.

Workaround: Use a display that does not require the HSYNC and VSYNC signals for synchronization. Check with your display manufacturer/supplier on the synchronization method used by the display.

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: With a single USB cable connected to the USB client port of the carrier board, there is a residual voltage of around 0.85V at the 3.3V rail of the SoM. Besides the residual voltage, no negative impact has been detected/reported. As the resistor R115 (560Ohm) limits the backfeeding current, no damage to the related module IO pin is expected.

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 the value of R115 to from 560R to 5.6k. Change the value of R116 from 1k to 10k. According to tests done with the Colibri iMX6, this reduces the residual voltage from 0.85V to 0.18V.