bbb hardware spec - victronenergy/venus GitHub Wiki

Victron version of the BeagleBone Enhanced

For the software / driver related notes on the bbe see the bbe related page.

Sancloud is making a custom beaglebone for us based on their Beaglebone Enhanced, but then:

  • Removing the sensors (accel/gyro and barometer)
  • Removing HDMI
  • Reducing the memory back to 512MB (CCGX has 256MB)
  • Putting the network port back to 10/100Mb
  • Removing all associated discrete components for deleted features
  • Removed NOR boot flash

Compared to a normal bbb, the bbe and therefore the Victron product, will have:

  • one extra USB port (total = two)
  • no 5V power jack
  • 4GB instead of 2GB (might be reduced back to 2GB, for cost reasons. CCGX has ~500MB)
  • add wifi and ble (RTL8723BU USB WIFI+BT module)

Similar to this BeagleBone Enhanced, there are also these products available on the market:

  • BBB stands for BeagleBone Black.
  • Seeedsudio's BeagleBone Green has no HDMI, and is therefore about $10 cheaper. It has 2 Grove connectors: one is on UART2, so takes out a VE.Direct port if wanted. The other Grove connector uses I2C2, so it can be used instead of the secondary CAN bus.
  • Seeedsudio's BeagleBone Green Wireless is similar to the BeagleBone Green. However, it has no ethernet, 4 USB ports, wifi and ble.

CAN bus

CAN Bus Port isolation
VE.Can CAN1 YES
CAN-BUS CAN0 (3rd party devices: e.g. LG Chem battery) NO
(Bus driver: SN65HVD1050 (recommend a 3.3V driver instead) (MPPT, CCGX...))

VE.Can port will be isolated, and includes a small isolated power supply for the can-transceiver. An alternative to the ADµM isolators must be found because they are $5,32 each. Using the ISO1050 with a separate dc/dc will probably be most economic. The port will not power any other nodes on the canbus network.

The second port is not isolated.

UARTS

Function Port Isolation tty
Debugging Console UART0 NO /dev/ttyO0
VE.Direct1 UART2 YES /dev/ttyO2
VE.Direct2 UART4 YES /dev/ttyO4
VE.Bus UART5 (with MK3 µC) YES /dev/ttyO5
UART3 (=TX only) conflicts with SPI_1 CS1 (NOT USED)

VE.Bus UART details

  • Galvanic isolation between BBB and MK3. No isolation between MK3 and VE.Bus, only an RS485 transceiver
  • VE.Bus Panel and VE.Bus remote standby pins are wired conforming to the new MK3 wiring spec.
  • MK3 PIC microcontroller powered from BBB cape
  • MK3 RST driven by BBB
  • MK3 BRK driven by BBB (Provisional, expected not to be needed in future)

RTC

PCF8523T on I2C2.

eeprom

... on I2C2. Currently not populated. Could be used to identify cape type and version.

USB

There’s only 1 USB port on the BBB. But there is one more on the custom beaglebone. Use an external 3rd party USB hub. Users that need only 1 port don’t need the HUB. Hub can be powered from the Cape.

Wifi and BLE

We'll use a custom beaglebone, that has both Wifi and BLE onboard.

Digital inputs / Pulse counters

5 Digital inputs on an RJ12 jack. These digital inputs operate at 3V3 levels, and also withstand 5V input. Each input has an internal 10k pull-up resistor to 3V3, so it can be connected to potential free relays or open collector/optocoupler outputs.

####Can be readily used as pulse counter inputs:####

  • S0 counter: for kWh, Heating, gas and water metering.
  • S0 is standardized acc. EN 62053-31
  • Minimum pulse/pause length is 30ms, so the maximum pulse frequency at 50% duty is about 17Hz

Tank monitor inputs

  • 3 tank level sensors, e.g. fresh water, black water, fuel.
  • connects to standard tank senders, 0...300

Battery Voltage

  • 1 input, 0...70V

Dropped because it won't be accurate since not differential, and no sense wires. Customers can better install a BMV or use battery voltage measured by connected solar charger or something else.

Temperature Measurement

  • 2 inputs, both for LM335Z sensors (the exact same sensors that the Multi's use)

PSU

8-70V power input. Output 5V 2500mA. The BBB needs 1A for the board only + 500mA for the USB port. To power an external HUB + USB devices an extra 500mA...1A is required.

At room temperature and 60V input, the user can draw a combined 2A out of the USB and 5V output connector in addition to the BeagleBones power consumption. If the ambient temperature rises, either the supply voltage or the output current should be lowered accordingly. An external 5V supply such as a powered USB hub may be used in such cases.

BeagleBone power requirements: The BBB needs a 4.3...5.8V supply. (=VDD_5V on the expansion headers). Rise time from 100mV to 4.3V needs to be <50ms. The power input is 20V tolerant, but the BBB's SOC is not powered outside the VDD range.

Relay

  • 1 user programmable relay.
  • Space for a second relay.
  • Must maintain position during reboot (For example when updating), but must drop when power fails (to avoid unwanted generator starts when power returns)

LCD

An LCD will not be included: the system will only run headless.

Buzzer

Depending on cost and space, a buzzer may be included.

Cape size

The board would ideally be the same size as the BBB. But with all the connectors that has not been possible to do. So it is larger.

Enclosure

See powerpoint containing photos of recent proto type

###Buttons on cape One button: the boot button

Future work

  • PWM output: e.g. to allow power control of a water heater to exactly match supply and demand