3. Using the DEVKIT¶

This chapter provides instructions for using HAIKOU CB-MINI-ITX, such as booting and how to configure and use I/O peripherals (e.g. serial console, Ethernet).

3.1. HAIKOU CB-MINI-ITX Overview¶

An overview of the available connectors and devices on HAIKOU CB-MINI-ITX is shown below.

_images/ringneck-overview.png — Fig. 3.1 HAIKOU CB-MINI-ITX with RINGNECK SOM-PX30-uQ7¶

3.2. Power Supply¶

HAIKOU CB-MINI-ITX can operate with a single 12V DC power supply. The 12V DC connector is highlighted below.

_images/ringneck-power_supply.png — Fig. 3.2 12V Power connector¶

Power can be controlled manually from the board using the Power control buttons and switches, located on the lower right side of the board.

Depending on the setting of Power Mode (Normally On / Normally Off) switch, HAIKOU CB-MINI-ITX will boot as soon as it receives power.

3.3. Control Buttons and Switches¶

The control buttons (see Fig. 3.1 HAIKOU CB-MINI-ITX with RINGNECK SOM-PX30-uQ7) provide the following functionality:

Power toggles the module power supply.
Reset triggers a module reset.
Batlow, Sleep and Wake are routed to GPIOs on the uQ7 module.

Several slider switches are located on the lower left:

LID SW is routed to a GPIO on the module, simulates lid open/close.
Power Mode (Normally On / Normally Off), as described above, sets the state after power loss.
BOOT SW (BIOS Disable / Normal Boot) forces SD card boot or the normal boot order, respectively.

3.4. CPU Fan¶

Operation in high environmental temperatures may require a CPU fan. The fan connector is located next to the bottom right corner of the Q7 expansion area.

_images/ringneck-cpu_fan.png — Fig. 3.3 Fan connector¶

Note

The fan is only necessary in high ambient temperatures. Under normal conditions RINGNECK SOM-PX30-uQ7 operates passively cooled.

3.5. Boot Order¶

The used boot order of RINGNECK SOM-PX30-uQ7 module depends on the value of the BIOS_DISABLE# signal. On HAIKOU CB-MINI-ITX this signal can be set using a slider switch (BOOT SW), with the two positions labeled Normal Boot, and BIOS Disable.

As shown in the table below, the BIOS Disable position disables the eMMC storage device:

	Normal Boot	BIOS Disable
1	eMMC storage	SD card
2	SD card	USB loader
3	USB loader

If no bootloader is found on any storage device, RINGNECK SOM-PX30-uQ7 will go into USB loader mode, showing up as a USB device on the USB-OTG port.

The electrical state of the BIOS_DISABLE# signal for both slider positions is shown below:

Slider Position	`BIOS_DISABLE#` signal
Normal Boot	Floating (on-module pull-up to 3.3V)
BIOS Disable	GND

3.6. USB Serial Console¶

HAIKOU CB-MINI-ITX contains an on-board Silicon Labs CP2102N USB-serial converter. Connect the included Micro-USB cable to the Micro-USB jack labeled USB-UART Bridge:

_images/ringneck-usb_uart.png — Fig. 3.4 USB UART¶

The serial converter does not require additional drivers on Windows and Linux.

For macOS, drivers are available from Silicon Labs: https://www.silabs.com/software-and-tools/usb-to-uart-bridge-vcp-drivers

RINGNECK SOM-PX30-uQ7 has two external UARTs:

UART0 is, by default, used for the serial console for interactive login.
UART1 is unused by default and can be freely used for machine-to-machine communications or other purposes.

The switch UART0 / UART1 cross-switches UART0 and UART1 between the RS232 / RS485 jack and the onboard USB-serial converter:

Switch Position	`RS232 / RS485` jack connected to:	USB-serial converter connected to:
`UART0`	UART0 (interactive console)	UART1
`UART1`	UART1	UART0 (interactive console)

For interactive login through the USB-serial converter, make sure the switch is on the UART1 position.

Note

UART1 is the name of the UART exposed on HAIKOU CB-MINI-ITX. It is actually connected to the UART5 controller on the PX30 SoC.

Incidentially, UART0 on HAIKOU CB-MINI-ITX is connected to the UART0 controller on the PX30 SoC.

Picocom can be used to connect via the serial line (assuming the USB-serial converter is USB0):

picocom -b 115200 /dev/ttyUSB0

Note

Make sure to disable software flow-control (XON/XOFF). Otherwise serial input may not be recognized.

After system boot-up, the login console appears on the terminal:

px30-uq7 login:

You can log in as root with password root.

3.7. RS-232 and RS-485¶

To connect via RS-232 or RS-485, connect to the RS232 / RS485 jack on HAIKOU CB-MINI-ITX.

_images/ringneck-rs232_rs485.png — Fig. 3.5 RS-232 connector¶

The switch labeled RS-232 / RS-485 selects between RS-232 and RS-485 mode on the jack.

In RS-485 mode, the switch labeled Full Duplex / Half Duplex selects full- or half-duplex mode, respectively. It has no effect in RS-232 mode, which is always full-duplex.

3.8. TTL UART¶

UART0 and UART1 are also available through the pin headers P12 UART0 and P30 UART1 next to the RS232 / RS485 jack. The signal level is 3.3V.

3.9. Ethernet¶

RINGNECK SOM-PX30-uQ7 has built-in Fast Ethernet (100Mbit/s) routed to a standard RJ-45 jack on HAIKOU CB-MINI-ITX.

The SD card that is shipped with the DEVKIT is configured to automatically retrieve an IP address via DHCP and provides SSH login on port 22.

3.10. SD-Card¶

RINGNECK SOM-PX30-uQ7 supports UHS SD cards and maximum writing speed on the SD card is 50MB/s. The practical writing and reading speeds depend on the capabilities of the inserted SD card.

3.11. USB Interfaces¶

RINGNECK SOM-PX30-uQ7 provides four USB ports:

1x USB 2.0 OTG
3x USB 2.0 Host

_images/ringneck-usb_otg.png — Fig. 3.6 USB 2.0 OTG port (dual-role port: can be used as a host or device interface)¶

_images/ringneck-usb_host.png — Fig. 3.7 USB 2.0 host ports¶

3.11.1. Connecting an External USB Drive¶

To connect a USB drive, plug it into one of the USB ports. The system should recognize the drive immediately. Check the kernel log to find the device name:

dmesg -f

You will be able to mount its partitions (assuming mapping to /dev/sdb1):

mkdir /mnt/usb1
mount /dev/sdb1 /mnt/usb1
ls /mnt/usb1

3.12. Display and Camera¶

RINGNECK SOM-PX30-uQ7 supports display output on the LVDS A interface and the camera on the LVDS B interface.

For MIPI-DSI and MIPI-CSI, the Qseven LVDS pins are used. Those pins are routed to the Video connector. This expansion slot uses a PCIe connector as mechanical connection, which allows easy development of adapter boards for various different display types.

Qseven Port	Function	Alternate Function
LVDS A	MIPI-DSI	LVDS
LVDS B	MIPI-CSI

_images/ringneck-video_connector.png — Fig. 3.8 Video connector pinout¶

The kernel devicetree defines the used display configuration. Example device trees for various output configurations are provided with the Board Support Package.

To specify which devicetree should be loaded on boot, edit the configuration variable FDT in the file /boot/extlinux/extlinux.conf. For example to enable support for DEVKIT ADDON CAM-TS-A01 write:

FDT /boot/px30-ringneck-haikou-video-demo.dtb

Filename	Functions
px30-ringneck-haikou.dtb
px30-ringneck-haikou-video-demo.dtb	Touchscreen display, camera Requires DEVKIT ADDON CAM-TS-A01

Filename

Functions

px30-ringneck-haikou.dtb

px30-ringneck-haikou-video-demo.dtb

Touchscreen display, camera

Requires DEVKIT ADDON CAM-TS-A01

3.13. RTC¶

RINGNECK SOM-PX30-uQ7 contains a real-time clock (RTC) on-module.

Note

This functionality is implemented in the optional Mule companion controller (see Section 12.4.4 Companion Controller 1 and Section 12.4.5 Companion Controller 2).

The RTC is read by the kernel on boot-up and used to set the system clock.

To check the RTC value, use hwclock:

$ hwclock
Thu 22 Oct 2022 01:49:20 PM CEST  -0.826662 seconds

The RTC will be automatically set to the system clock on shutdown, so you can set the system clock using the date command and reboot to update the RTC:

date --set 2022-10-22
date --set 04:12:33

You can also update the RTC immediately, again with hwclock:

hwclock -w

3.14. SPI and I2C¶

SPI and I2C interfaces are both available on the pin header labeled SPI+I2C+1-Wire. RINGNECK SOM-PX30-uQ7 does not support 1-Wire.

Additional I2C buses are available on the SMBUS header. Note that SMB_DAT, SMB_CLK, SMB_ALERT# are not supported by RINGNECK SOM-PX30-uQ7.

_images/ringneck-spi_i2c.png — Fig. 3.9 I2C and SPI header¶

_images/ringneck-smbus.png — Fig. 3.10 SMBUS header¶

For I2C, the i2c-tools package is available in Debian:

apt-get install i2c-tools

3.14.1. Linux I2C Bus Numbering¶

Linux identifies each I2C bus by a bus number. The table below shows the mapping between Q7 names, Linux bus number and HAIKOU CB-MINI-ITX header.

Q7 signals	Linux bus #	Header(s)	Label on Header
GP2_I2C_DAT/LVDS_DID_DAT GP2_I2C_CLK/LVDS_DID_CLK	1	`SMBus` & `Video connector`	`DID_DAT` `DID_CLK`
GP0_I2C_DAT GP0_I2C_CLK	2	`SPI+I2C+1-Wire`	`I2C_DAT` `I2C_CLK`
eDP0_HPD#/LVDS_BLC_DAT eDP1_HPD#/LVDS_BLC_CLK	3	`SMBus` & `Video connector`	`BLC_DAT` `BLC_CLK`

Q7 signals

Linux bus #

Header(s)

Label on Header

GP2_I2C_DAT/LVDS_DID_DAT

GP2_I2C_CLK/LVDS_DID_CLK

SMBus & Video connector

DID_DAT

DID_CLK

GP0_I2C_DAT

GP0_I2C_CLK

SPI+I2C+1-Wire

I2C_DAT

I2C_CLK

eDP0_HPD#/LVDS_BLC_DAT

eDP1_HPD#/LVDS_BLC_CLK

SMBus & Video connector

BLC_DAT

BLC_CLK

The other I2C buses (as reported by i2cdetect -l) are internal to the module and not routed to the Q7 connector.

3.15. GPIOs¶

Eight GPIOs are provided on the pin header labeled GPIO.

The location on HAIKOU CB-MINI-ITX is displayed below:

_images/ringneck-gpio.png — Fig. 3.11 GPIO header¶

The GPIO numbers printed on the board refer to numbers used in the Qseven specification. They are different than the ones used in Linux via /sys/class/gpio.

The mapping is shown in the following table:

Q7 signal	CPU pin	Linux GPIO #
GPIO0	GPIO3_C6	118
GPIO1	GPIO3_D0	120
GPIO2	GPIO3_C7	119
GPIO3	GPIO3_D1	121
GPIO4	GPIO3_C0	112
GPIO5	GPIO3_A2	98
GPIO6	GPIO3_A1	97
GPIO7	GPIO2_B6	78

To calculate the Linux GPIO # for CPU pins that are not listed in this table, use the following formula:

n = (block_number * 32) + (sub_block_number * 8) + index

Where:

block_number … index of the block number
sub_block_number … the alphabetical index of the block name, minus 1
index … the pin number within the block

Example:

GPIO3_C6 -> (3 * 32) + (2 * 8) + 6 = 118

To enable a GPIO, write the Linux GPIO # to the special export file:

$ echo 118 > /sys/class/gpio/export
$ cat /sys/class/gpio/gpio118/direction
in
$ cat /sys/class/gpio/gpio118/value
0

To set the direction to output, write out in the GPIO’s direction file:

echo out > /sys/class/gpio/gpio118/direction
echo 1 > /sys/class/gpio/gpio118/value

The GPIO will be set to a value of 1 (high at 3.3V).

3.16. Audio¶

HAIKOU CB-MINI-ITX provides two audio connectors for input and output. Line-in is on top and Headphones is on bottom of the audio connector.

Note

The codec on HAIKOU CB-MINI-ITX only supports a sample rate 48kHz. This restriction only applies to this specific codec on HAIKOU CB-MINI-ITX.

The I2S bus on RINGNECK SOM-PX30-uQ7 module supports a sample rate up to 192kHz.

Additionally, an expansion connector for I2S audio is available on the bottom row of the carrier board:

_images/ringneck-i2s.png — Fig. 3.12 Audio jacks and I2S header¶

3.17. CAN Bus¶

HAIKOU CB-MINI-ITX provides a CAN connector on the bottom row.

_images/ringneck-can.png — Fig. 3.13 CAN header¶

Note

CAN feature is only available on RINGNECK SOM-PX30-uQ7 with an STM32, see (Section 12.4.4 Companion Controller 1).

3.18. CTRL I/O Connector¶

HAIKOU CB-MINI-ITX provides signals for watchdog trigger in- and output, SoM PMIC power-on input, reset and external display power enable.

_images/ringneck-ctrl_io.png — Fig. 3.14 CTRL I/O header¶

3.19. MISC Connector¶

HAIKOU CB-MINI-ITX provides signals for thermal overheat of external hardware and the processor, utility signals for SD and GPO0.

_images/ringneck-misc_io.png — Fig. 3.15 MISC header¶

3.20. JTAG Connector¶

The board provides UPDI signals on the JTAG connector. RINGNECK SOM-PX30-uQ7 does not support JTAG, but the ATtiny (see Section 12.4.5 Companion Controller 2) can be flashed over JTAG connector pins.

_images/ringneck-jtag.png — Fig. 3.16 JTAG header¶

JTAG header	Function
TDI	UPDI-TX
TDO	UPDI-RX