Dahlia Carrier Board Issue Tracker

The following table contains known issues, scheduled bug fixes, and feature improvements for the Dahlia Carrier Board.

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Issue #	Status	Subject	Affected Versions	Implemented In

HAR-9017	Known Issue	Overvoltage protection triggered when powering up the Dahlia V1.1	Dahlia Carrier Board V1.1A Dahlia Carrier Board V1.1B Dahlia Carrier Board V1.1C	Dahlia Carrier Board V1.1D
Customer Impact: Hot-plugging a 26.4V power supply to the carrier board may trigger the protection IC (IC18) and prevent the product from powering up. Description: The carrier board features a protection IC (IC18) that protects the product from various power-related error scenarios, namely: overvoltage, overcurrent, undervoltage, reverse polarity. In case a power supply providing a voltage (26.4V) near the high threshold of the input voltage range (5V to 24V ±10%) 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 C95 and the capacitors on the switched side (C247, C248, etc..). This may trigger the overcurrent protection, causing the board to not power up. In this case, the protection IC's fault indication LED (LED8) is going to blink to indicate the fault condition. Workaround: Unsoldering the capacitor C95 will improve the power hot-plug capability of the product. The issue is going to be resolved in newer versions of the product.
HAR-8935	Known Issue	The RC element on the PCIe reset signal contributes to violating the PCIe specification	Dahlia Carrier Board V1.1A Dahlia Carrier Board V1.0B Dahlia Carrier Board V1.1B	Dahlia Carrier Board V1.1C
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 Dahlia Carrier 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 C141. 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.
HAR-8814	Known Issue	The carrier board turns off when a cable is connected to the USB-C FTDI debug connector	Dahlia Carrier Board V1.1A Dahlia Carrier Board V1.0B Dahlia Carrier Board V1.0C Dahlia Carrier Board V1.1B	Dahlia Carrier Board V1.1C
Customer Impact: The module may reset or turn off, or the carrier board may turn off when a cable is being connected to the USB-C connector of the FTDI debug port while the board is turned on. Description: Due to a race condition between the pull-up voltage at the gates of the transistor level shifters, the DBG_PWR_BTN#, DBG_FORCE_OFF#, DBG_RESET#, DBG_RECOVERY#, and the FTDI_JTAG_TRST# signals can get unintentionally triggered when connecting a cable to the USB-C connector of the FTDI debug port. This may reset or shut down the module, or shut down the power rails of the carrier board. Workaround: Connect the cable to the USB-C connector of the FTDI debug port before powering on the carrier board. As an alternative solution, the resistors R102, R109, R115, R120, and R245 can be replaced with resistors having a resistance of 1MOhm. This slows down the transistor level shifter circuits and makes sure that the power control signals are not triggered when connecting the cable to the USB-C connector of the FTDI debug port. The same improvement is going to be implemented in future versions of the product.
HAR-8427	Known Issue	Signal distortion on the audio codec's "Line In" input	Dahlia Carrier Board V1.0A Dahlia Carrier Board V1.1A Dahlia Carrier Board V1.0B Dahlia Carrier Board V1.0C	Dahlia Carrier Board V1.1B
Customer Impact: The audio signals from the "Line In" input (connector X15) are distorted and the amplitudes of the signals are smaller than intended. There is crosstalk from the "Line In" input (connector X15) to the "Mic In" input (connector X14). Description: The 10k pull-down resistors R251 and R254 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 R251 and R254 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.
HAR-8291	Known Issue	The LED status signals of the on-module Ethernet PHY are swapped on the Dahlia	Dahlia Carrier Board V1.1A Dahlia Carrier Board V1.0B Dahlia Carrier Board V1.0C
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 Dahlia 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.
HAR-8017	Known Issue	CSI_1_MCLK Voltage Level is not 3.3V	Dahlia Carrier Board V1.0A Dahlia Carrier Board V1.1A Dahlia Carrier Board V1.0B Dahlia Carrier Board V1.0C
Customer Impact: In case a MIPI CSI-2 camera requires the CSI_1_MCLK signal (pin #12 of X16), and in case it requires this signal to be at 3.3V level, then the current voltage level of the signal won't be compatible with the camera. Description: On the MIPI CSI-2 interface used on the Dahlia V1.1A, all of the single-ended signals are at 3.3V level, except for the CSI_1_MCLK signal (pin #12 of X16), which is at 1.8V level. Workaround: In case a MIPI CSI-2 camera requires the CSI_1_MCLK signal (pin #12 of X16), and in case it requires this signal to be at 3.3V level, it could be level shifted on custom carrier boards.
HAR-6255	Known Issue	CTRL_FORCE_OFF_MOCI# is disabled	Dahlia Carrier Board V1.0C	Dahlia Carrier Board V1.1A
Customer Impact: After a shutdown, the main supplies are not turned off. For turning off the main power rails, the power button needs to be pressed for >7s. Description: R96 is not assembled on the product version V1.0C. This disables the “kill-feature” entirely. Therefore, after a shutdown, the main supplies are not turned off. For turning off the main power rails, the power button needs to be pressed for >7s.
HAR-3672	Known Issue	CTRL_FORCE_OFF_MOCI# has pull-down instead of pull-up resistor	Dahlia Carrier Board V1.0A Dahlia Carrier Board V1.0B	Dahlia Carrier Board V1.1A
Customer Impact: The CTRL_FORCE_OFF_MOCI# signal is permanently pulling down the kill input of the power button IC LTC2954 (IC10). The LTC2954 ignores the kill input for the first 512ms after turning on. After this internal timer is expired, the kill signal will power off the system. This means pressing the power button on the Dahlia carrier board will turn on the power only for 512ms. Description: The CTRL_FORCE_OFF_MOCI# input on the Dahlia carrier board features a 1MΩ pull-down resistor instead of a pull-up resistor. In the Verdin family definition, the CTRL_FORCE_OFF_MOCI# signal is specified as open-drain signal that is 5V tolerant. The pull-up resistor is supposed to be on the carrier board. Without this pull-up resistor, the CTRL_FORCE_OFF_MOCI# remains low and therefore is asserted all the time. The CTRL_FORCE_OFF_MOCI# signal is permanently pulling down the kill input of the power button IC LTC2954 (IC10). The LTC2954 ignores the kill input for the first 512ms after turning on. After this internal timer is expired, the kill signal will power off the system. This means pressing the power button on the Dahlia carrier board will turn on the power only for 512ms. Workaround: Removing R96 disables the CTRL_FORCE_OFF_MOCI# signal on the Dahlia carrier board. However, this disables the “kill-feature” entirely. Therefore, after a shutdown, the main supplies are not turned off. For turning off the main power rails, the power button needs to be pressed for >7s. Besides this inconvenience, the modification is compatible with all Verdin module versions.
HAR-3351	Known Issue	Cypress USB-C PD detection chip does not behave as expected on Type-A to Type-C cables	Dahlia Carrier Board V1.0A Dahlia Carrier Board V1.0B Dahlia Carrier Board V1.0C	Dahlia Carrier Board V1.1A
Customer Impact: Depending on the cable used, the board can be turned on, even though the USB power source is not capable of delivering enough power. This may cause the power source USB port to trigger overcurrent protection. The power supplies on the carrier board may trigger undervoltage protection at higher current consumption (e.g., during booting of the module). Description: Because of the unexpected behaviour of the Cypress USB-C PD detection chip, the Dahlia board is turning on even with an improper USB power source. Workaround: Use the Dahlia Carrier board only with suitable USB power sources. Alternatively, USB Type-A to Type-C cables or adapters without a pull-up resistor on CC line can be used.
HAR-3302	Known Issue	System doesn't boot with Verdin DSI to LVDS Adapter attached	Dahlia Carrier Board V1.0A Dahlia Carrier Board V1.0B Dahlia Carrier Board V1.0C	Dahlia Carrier Board V1.1A
Customer Impact: When using the Dahlia in combination with a Verdin DSI to LVDS Adapter (connected to X17) and a 10.1” LVDS display (attached to the adapter), the carrier board won't turn on or will shut down if the power supply input voltage is < 7V. Description: When using the Dahlia in combination with a Verdin DSI to LVDS Adapter (connected to X17) and a 10.1” LVDS display (attached to the adapter), the carrier board won't turn on or will shut down if the power supply input voltage is < 7V. Workaround: Use USB-C PD power supplies with at least 9V or power the board over the barrel connector with at least 7V. Use a good USB cable. The quality of the cables has an impact on the +V_SUPPLY_FILT voltage stability.