The following table contains known issues, scheduled bug fixes, and feature improvements for the Ixora Carrier Board.
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Customer Impact: In the off state, there is a potential backfeeding from the pull-up resistor of the WAKE1_MICO# signal on the carrier board to the Apalis SoM/SoC. However, as the pull-up resistor has a value of 10kOhm, the backfeeding current is small (up to 0.33mA). Therefore, there is no real impact expected.
Description: The WAKE1_MICO# signal is used to wake up the Apalis SoMs from the suspend state (sleep state). This signal is served with a regular GPIO (with wake capability). The IO rail of this GPIO is turned off during the off state. Therefore, by design, it is not possible to use the WAKE1_MICO# signal for waking the SoM up from the off state (the SoM can only be woken up from the off state by asserting the RESET_MICO# signal or via a complete power cycle). In the affected HW versions of the Ixora, the WAKE1_MICO# signal is pulled up to the 3.3V (always-on) rail. The 3.3V (always-on) rail remains on, even if the SoM is shut down (off state). As the IO rail of the GPIO pin serving the WAKE1_MICO# signal is turned off during the off state, a small backfeeding current can occur in the off state from the pull-up resistor on the carrier board into the SoM/SoC. For the above reasons, it is recommended to pull up the WAKE1_MICO# to the 3.3V_SW (switched), which is turned off in the off state.
Workaround: The 10kOhm pull-up resistor on the carrier board (R146) can be removed, if the related internal pull-up resistor of the SoC is enabled or the wake function is entirely disabled. This eliminates the potential backfeeding over the WAKE1_MICO# signal.
Customer Impact: The overcurrent protection can unintentionally trigger and shut down the system in combination with the Apalis iMX8QM or Apalis TK1.
Description: Ixora Carrier Board (V1.1 and V1.0) power supply is designed to supply a maximum output current of 6.7A at 3.3V rail (Ixora V1.1) and 5A at 3.3V rail (Ixora V1.0). The buck converter on the Ixora Carrier Board features Output Over-Current Protection (OCP), which shuts down the power supply immediately if the output current exceeds the maximum output current limit. The peak current consumption of the Apalis iMX8QM or Apalis TK1 V1.0 module can be higher than 5A under stress conditions like processor / GPU intensive tasks. Under such conditions, the Ixora Carrier Board power supply might shut down due to OCP limits. A higher continuous current also results in rising in temperature of the carrier board near the power supply region, which affects the current sense resistor value and lead/solder-joint resistance. Customers who are evaluating/testing Apalis iMX8QM or Apalis TK1 (V1.0) module with Ixora Carrier Board can use the below-mentioned workaround. We will develop a new power supply for Ixora Carrier Board that addresses this issue.
Customer Impact: The Ethernet port fails the compliance test for 10BASE-T. 100BASE-TX and 1000BASE-T are passing.
Description: All currently available Toradex Apalis modules do not require a center tap voltage. Only 100nF capacitors are required on the center tap pins of the magnetics. Connecting the center tap signals together can degrade the signal quality and is therefore not recommended. Currently, the center-tap circuit is assembled through R73-R76, C72/C73, and L20. This assembly has a measurable negative influence on the quality of the 10Mbps Ethernet signals on modules with Microchip's KSZ9031 Ethernet PHY. We haven't seen any impact on other PHY's or to 100BASE-TX and 1000BASE-T.
Customer Impact: In combination with the Apalis TK1, the DDC information of some monitors cannot be read successfully, and therefore, no picture is shown.
Description: The Apalis TK1 module, combined with the Ixora carrier board, shows issues with some HDMI monitors. In case of failure, the module cannot read the monitor's DDC information and will not show any picture. It depends on the monitor whether the issue appears. In some module/monitor combinations, the problem occurs only when hot-plugging the HDMI cable, while in other cases, the issue also appears when booting the module. The issue only appears if the Apalis TK1 module is combined with the Ixora Carrier Board. Apalis T30 and Apalis iMX6 are not affected by this erratum. The issue is caused by an incompatible low logic level of the DDC interface. The Ixora board features the Nexperia IP4791CZ12 HDMI ESD protection and level shifter. This device is used for level shifting the 5V HDMI DDC signals to the 3.3V level of the Apalis module. According to the datasheet, the maximum output low-level of this device is 0.92V for the 3.3V level output. The maximum input low-level of the Apalis TK1 2GB V1.1A DDC signals is 0.45V.
