Author: Lukas Wunner
The password of user "pi" is "nmwone" on all prototypes.
Each prototype has a sticker with the MAC address of the LAN interface,
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LAN switch and WLAN interface. IP addresses are configured with DHCP.
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Attach the protoype to a LAN with a DHCP server, scan the LAN with
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a tool such as "nmap" or "Advanced IP Scanner", then determine the
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prototype's IP address by searching the scan output for the MAC address
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on the sticker.
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Log in with ssh.
By default, RS485-0 (/dev/ttyAMA0) is used as console. So So if you are
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unable to log in over the LAN, try logging in via serial console by
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attaching an RS-485 USB serial adapter between your PC and the RS485-0
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port.
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Set the baud rate to 115200.
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If you need the RS485-0 port for a
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different purpose or would like to prevent tampering with the prototype,
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disable its use as a console by removing the "console=ttyAMA0" parameter
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from /boot/cmdline.txt.
RS485-1 is available as /dev/ttyS0 and can likewise be configured as
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console.
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The RS485 signals are on the two innermost pins (3 & 4) of
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the RJ-11 plug.
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The adjacent pins (2 & 5) are connected to ground.
There is a simple script called "hwtest.sh" in the home directory of
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user "pi" which we've used to test each prototype.
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The commands used
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in the script show how to access each of the prototype's functions and
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may serve as a template or inspiration for your application.
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Feel free
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to re-execute the script using "sudo bash hwtest.sh".
The WLAN interface currently doesn't use the MAC address on the sticker,
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but rather the permanent MAC address assigned by the chip manufacturer.
The Bluetooth interface currently needs to be set up manually using
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"hciattach /dev/ttyUSB0 any". We'll see to it that in the future
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it gets set up automatically using the kernel's serdev infrastructure.
The LAN switch works but is currently not configurable through its
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Linux driver.
The ADC and DAC are exposed in /sys/bus/iio/devices/. Note that the
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numbering of the devices (0 and 1) is arbitrary and may change on
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every reboot.
Convert the raw value read from the ADC in "in_voltage0-voltage1_raw"
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using the formula (($raw * 12500) >> 20) + 12500 to get the voltage in mV.
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The ADC has high precision but is relatively slow with up to 80 ms
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for each conversion.
Write a value between 0 and 4095 to the DAC in "out_voltage0_raw"
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to output a voltage between 0 and 10 V.
LEDs are exposed in /sys/class/leds, turn them on or off by writing
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255 or 0 to their "brightness" file.
The electromagnetic relais can be toggled by accessing GPIO pin 9 from
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user space.
The watchdog can be enabled with:
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gpio mode 4 out ; gpio write 4 1
The RTC is powered by a supercap which allows it to maintain the time
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and date for a few hours even if no power source is attached. If the
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prototype is disconnected from a power source for a longer period,
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then the time and date needs to be resynchronized using NTP.
The TPM currently doesn't use its interrupt. It shouldn't impact the
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chip's function in any way, aside from a minor performance penalty.
Currently no kernel driver is compiled in for the MBUS RF-module.
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It can be accessed from user space with spidev:
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The kernel used on the prototypes was generated from the following branches:
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https://github.com/RevolutionPi/kernelbakery/commits/connect-flat
The device tree overlay for the Connect Flat Prototype is located in the
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linux repository at:
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arch/arm/boot/dts/overlays/revpi-connect-flat-overlay.dts
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It provides you with an overview of the chips present on the prototype.
The image used on the prototypes was generated using our regular
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imagebakery tool available on GitHub, with a few small manual tweaks
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to add basic support for the prototypes.
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