Customer Impact: Hot-plugging a 26.4V power supply to the carrier board may trigger the protection IC (IC25) and prevent the product from powering up.

Description: The carrier board features a protection IC (IC25) that protects the product from various power-related error scenarios, namely: overvoltage, overcurrent, undervoltage, reverse polarity. In case a power supply providing a voltage near the high threshold of the input voltage range (26.4V) gets hot-plugged to the carrier board, ringing may form at the input of the protection device. The energy is bouncing between the low-ESR capacitors C98 and the capacitors on the switched side (C106, C107, C174). This may trigger the overcurrent protection, causing the board to not power up. In this case, the protection IC's fault indication LED (LED17) is going to blink to indicate the fault condition.

Workaround: Unsoldering the capacitor C98 will improve the power hot-plug capability of the product. The issue is going to be resolved in newer versions of the product.

Customer Impact: PCIe devices connected to the PCIe interface of the carrier board may not get detected properly or malfunction.

Description: According to the PCIe specifications, software needs to wait a minimum of 100ms before sending a configuration request to a PCIe device after enabling the power and the clock. The Verdin specification provides a dedicated reset signal for the PCIe interface (PCIE_1_RESET#). The Verdin Development Board features an RC delay circuit on this signal. This circuit consists of a 10uF capacitor and a 10kOhm pull-up resistor, resulting in a time constant of 100ms. The actual time it takes for the device to get out of the reset state is influenced by the threshold level of the device's reset input and component tolerances as well. These factors together make the timing unpredictable. As a consequence, a PCIe device may still be in the reset state when the driver is sending the first configuration requests. The issue does not necessarily manifest in case of all potential PCIe devices, and can be temperature-dependent as well.

Workaround: By eliminating the RC delay circuit from the reset signal, the module's reset timing can be fully controlled by the PCI_1_RESET# signal. For achieving that, remove the 10uF capacitor C173. The change prevents the described issue from happening. The change is going to be implemented in future versions of the product. Alternatively, the delay between releasing the reset and initiating the configuration requests can be increased in the driver. However, this is not the preferred method as this requires modifications to be done to the standard drivers.

Customer Impact: The audio signals from the "Line In" input (connector X21) are distorted and the amplitudes of the signals are smaller than intended. There is crosstalk from the "Line In" input (connector X21) to the "Mic In" input (connector X22).

Description: The 10k pull-down resistors R135 and R138 connected to the pins 26 and 24 of the audio codec (IC28) affect the functionality of the device’s internal multiplexers and signal amplifiers. The analog input pins of the audio codec shift the input DC offset to their internal virtual ground VMID. The external pull-down resistors are affecting this DC offset, causing the opening of the internal multiplexer’s analog signal switches and the saturation of the amplifier's outputs. This leads to the distortion of the "Line In" signals (only the positive polarity parts of the input signals are recorded) and crosstalk from the "Line In" input to the "Mic In” input.

Workaround: Remove the pull-down resistors R135 and R138 from the carrier board. This makes the audio codec’s "Line In" and "Mic In” inputs work properly. Please see the PDF errata document in the "Errata/Known Issues" section for more information.

Customer Impact: The roles of the Ethernet link and activity LEDs are swapped (the wrong Ethernet LED is turned on or is blinking).

Description: The KSZ9131 Ethernet PHY on the Verdin modules has two LED outputs (ETH_1_LED_1 and ETH_1_LED_2) which are used for indicating the link and activity statuses on the bus. These LEDs are available on pin 235 and 237 of the module edge connector, respectively. ETH_1_LED_1 (pin 235) is intended to indicate the activity status, while ETH_1_LED_2 (pin 237) is intended to indicate the link status. On the PCB versions 1.0 and 1.1, these two signals are swapped. In the next revision of the carrier board PCB, the connections will be corrected. In the Verdin Development Board datasheet, the corrected connections are shown.

Workaround: For custom carrier board designs, the correct LED connections should be implemented. A potential workaround could be flipping the roles and behavior of the LED outputs of the on-module Ethernet PHY in software. However, this is not supported by the related driver.

Customer Impact: The audio output is significantly attenuated or not audible at all when the audio codec's speaker output is used in combination with external speakers connected in a stereo setup. The issue does not affect the speaker output when the external speakers are connected in a mono setup.

Description: The audio codec featured on the Verdin Development Board V1.1 includes an integrated speaker driver. The Verdin Development Board V1.1 provides two operating modes for the audio codec speaker output: mono and stereo. In a mono setup, one or two external speakers are connected as a Bridge Tied Load (BTL) to the connectors X28 and/or X29. In this setup, the speaker output should work fine. In a stereo setup, two external speakers are connected to the connector X13. In this case, one end of each speaker’s coil is connected to the common ground pin (GND), the other ends are connected to the audio codec IC through the capacitors C182 or C183, respectively. The capacitors C182 (1uF) and C183 (1uF), in conjunction with the speaker’s impedance (8Ohm), form high-pass filters. The cut-off frequency of the high-pass filters is around 20 kHz. This frequency is at the upper edge of the audible frequency range, and lower frequencies are attenuated/filtered out by the aforementioned high-pass filter.

Workaround: A partial workaround has already been applied to the Verdin Development Board V1.1A: 0Ohm resistors have been assembled instead of the capacitors C182, C183. To complete the workaround, external capacitors connected in series with the external speakers are required (see Figure 3). The exact values of the capacitors depend on the desired cut-off frequency and the impedance of the speakers. Some applications may not require the complete audible frequency range of approx. 20Hz – 20Hz to be available. The low-frequency limit is 100Hz for many low-power speakers, so it may be unnecessary to go below this cut-off frequency. For 8Ohm speakers, our recommendation is to use either 220uF series capacitors for a cut-off frequency of approx. 90Hz or 470uF for 42Hz respectively (minimum 6.3V rated in both cases). Please check Errata #6 in the Verdin Development Board errata for more information.

Customer Impact: During a reset cycle (software or button initiated), the CTRL_PWR_EN_MOCI# signal can go low for power cycling the peripherals on the carrier board. This is disabling also the +V1.8_SW which means the CTRL_FORCE_OFF_MOCI# goes low and triggers the kill input of IC16. IC16 will then kill the main power of the module. This means resetting the module can cause an unintentionally power-off of the system.

Description: According to the Verdin specifications, the CTRL_FORCE_OFF_MOCI# is an open-drain output of the module which is 5V tolerant and requires a pull-up resistor on the carrier board. On the Verdin Development Board V1.0B, the CTRL_FORCE_OFF_MOCI# is pulled up to the +V1.8_SW rail. Unfortunately, this rail is switched by the CTRL_PWR_EN_MOCI# signal. During a reset cycle (software or button initiated), the CTRL_PWR_EN_MOCI# signal can go low for power cycling the peripherals on the carrier board. This is disabling also the +V1.8_SW which means the CTRL_FORCE_OFF_MOCI# goes low and triggers the kill input of IC16. IC16 will then kill the main power of the module. This means resetting the module can cause an unintentionally power-off of the system.

Workaround: Removing R80 disables the CTRL_FORCE_OFF_MOCI# signal on the Verdin Development Board. However, this disables the “kill-feature” entirely. Therefore, after a shutdown, the supplies are not turned off which prevents the system to be turned on by using the power button. For turning on the system, either power cycle the whole board or turn off the main 3.3V rail on the carrier board by pressing the power button >3s. Besides this inconvenience, the modification is compatible with all Verdin module versions.

Description: The position of LED21, LED22, LED23, LED24 in the general-purpose LEDs and Switches area is not consistentwith the order of related signals available on the connector X38.

Workaround: Users should check table 3.14.2.1.5 of the product datasheet to avoid confusion when using this product feature.