Comms Cape Gateware for BeagleV-Fire

The comms cape provides an array of communication protocols including

one RS485,
one CAN,
two analog 4-20 mA current loops,
two 3A 50V interfaces allowing the control of high current loads.

Cape schematics, layout, and mechanicals

For the schematics, layout, and mechanicals of the cape, please refer to Beaglebone Industrial Comms Cape.

Usage

Firstly, the comms cape gateware must be compiled and updated on the beagleV-Fire. This can be done by using the build-bitstream.py script in the gateware repository with the cape_comms.yaml build option file.

python3 build-bitstream.py build-options/cape_comms.yaml

CAN

RS485

The RS485 interface is connected to UART4 on the BeagleV-Fire. It can be accessed using /dev/bone/uart/4 in Linux.

Sink drivers

The sink drivers are connected to the P9_15 and P9_23 GPIOs. They can be controlled by writing to the GPIOs by:

echo 425 > /sys/class/gpio/export
echo 431 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio425/direction
echo out > /sys/class/gpio/gpio431/direction
echo 1 > /sys/class/gpio/gpio425/value
echo 1 > /sys/class/gpio/gpio431/value

Current loops

The current loops are connected to the ADC inputs of the BeagleV-Fire at pins P9_35 and P9_36. They can be accessed once QSPI is enabled in the comms cape device tree overlay. The current loops can be read by:

cat /sys/bus/iio/devices/iio:device0/in_voltage5_raw #Current Loop A
cat /sys/bus/iio/devices/iio:device0/in_voltage6_raw #Current Loop B

Voltage to current conversion will have to be done in software.

Pinout

The full pinout for the cape interface spec can be found here . You can also see the pinout below, refer to the last column for comms-cape specific pins.

P8 Header

Signal	Control	Irq #	Description
P8_1	n/a	n/a	GND
P8_2	n/a	n/a	GND
P8_3	MSS GPIO_2[0]	53	User LED 0
P8_4	MSS GPIO_2[1]	53	User LED 1
P8_5	MSS GPIO_2[2]	53	User LED 2
P8_6	MSS GPIO_2[3]	53	User LED 3
P8_7	MSS GPIO_2[4]	53	User LED 4
P8_8	MSS GPIO_2[5]	53	User LED 5
P8_9	MSS GPIO_2[6]	53	User LED 6
P8_10	MSS GPIO_2[7]	53	User LED 7
P8_11	MSS GPIO_2[8]	53	User LED 8
P8_12	MSS GPIO_2[9]	53	User LED 9
P8_13	core_pwm[1] @ 0x41500000	n/a	PWM_2:1
P8_14	MSS GPIO_2[11]	53	User LED 11
P8_15	MSS GPIO_2[12]	53	GPIO
P8_16	MSS GPIO_2[13]	53	GPIO
P8_17	MSS GPIO_2[14]	53	GPIO
P8_18	MSS GPIO_2[15]	53	GPIO
P8_19	core_pwm[0] @ 0x41500000	n/a	PWM_2:0
P8_20	MSS GPIO_2[17]	53	GPIO
P8_21	MSS GPIO_2[18]	53	GPIO
P8_22	MSS GPIO_2[19]	53	GPIO
P8_23	MSS GPIO_2[20]	53	GPIO
P8_24	MSS GPIO_2[21]	53	GPIO
P8_25	MSS GPIO_2[22]	53	GPIO
P8_26	MSS GPIO_2[23]	53	GPIO
P8_27	MSS GPIO_2[24]	53	GPIO
P8_28	MSS GPIO_2[25]	53	GPIO
P8_29	MSS GPIO_2[26]	53	GPIO
P8_30	MSS GPIO_2[27]	53	GPIO
P8_31	core_gpio[0] @ 0x41100000	126	GPIO
P8_32	core_gpio[1] @ 0x41100000	127	GPIO
P8_33	core_gpio[2] @ 0x41100000	128	GPIO
P8_34	core_gpio[3] @ 0x41100000	129	GPIO
P8_35	core_gpio[4] @ 0x41100000	130	GPIO
P8_36	core_gpio[5] @ 0x41100000	131	GPIO
P8_37	core_gpio[6] @ 0x41100000	132	GPIO
P8_38	core_gpio[7] @ 0x41100000	133	GPIO
P8_39	core_gpio[8] @ 0x41100000	134	GPIO
P8_40	core_gpio[9] @ 0x41100000	135	GPIO
P8_41	core_gpio[10] @ 0x41100000	136	GPIO
P8_42	core_gpio[11] @ 0x41100000	137	GPIO
P8_43	core_gpio[12] @ 0x41100000	138	GPIO
P8_44	core_gpio[13] @ 0x41100000	139	GPIO
P8_45	core_gpio[14] @ 0x41100000	140	GPIO
P8_46	core_gpio[15] @ 0x41100000	141	GPIO

P9 Header

Signal	Control	Irq #	Description
P9_1	n/a	n/a	GND
P9_2	n/a	n/a	GND
P9_3	n/a	n/a	VCC 3.3V
P9_4	n/a	n/a	VCC 3.3V
P9_5	n/a	n/a	VDD 5V
P9_6	n/a	n/a	VDD 5V
P9_7	n/a	n/a	SYS 5V
P9_8	n/a	n/a	SYS 5V
P9_9	n/a	n/a	NC
P9_10	n/a	n/a	SYS_RSTN
P9_11	MMUART4	94	UART4 RX <— For RS485
P9_12	core_gpio[1] @ 0x41200000	143	GPIO
P9_13	MMUART4	94	UART4 TX <— For RS485
P9_14	core_pwm[0] @ 0x41400000	n/a	PWM_1:0
P9_15	core_gpio[4] @ 0x41200000	146	GPIO
P9_16	core_pwm[1] @ 0x41400000	n/a	PWM_1:1
P9_17	MSS SPI0	54	SPI0 CS
P9_18	MSS SPI0	54	SPI0 MOSI
P9_19	MSS I2C0	58	I2C0 SCL
P9_20	MSS I2C0	58	I2C0 SDA
P9_21	MSS SPI0	54	SPI0 MISO
P9_22	MSS SPI0	54	SPI0 SCLK
P9_23	core_gpio[10] @ 0x41200000	152	GPIO
P9_24	CAN_1_RXBUS	n/a	CAN RX <— For CAN
P9_25	CAN_1_TX_EBL	154	CAN TX EBL
P9_26	CAN_1_TXBUS	n/a	CAN TX
P9_27	core_gpio[14] @ 0x41200000	156	GPIO
P9_28	MSS SPI1	55	SPI1 CS
P9_29	MSS SPI1	55	SPI1 MISO
P9_30	core_gpio[17] @ 0x41200000	159	GPIO
P9_31	MSS SPI1	55	SPI1 SCLK
P9_32	n/a	n/a	VDD ADC
P9_33	n/a	n/a	ADC input 4
P9_34	n/a	n/a	AGND
P9_35	n/a	n/a	ADC input 6
P9_36	n/a	n/a	ADC input 5
P9_37	n/a	n/a	ADC input 2
P9_38	n/a	n/a	ADC input 3
P9_39	n/a	n/a	ADC input 0
P9_40	n/a	n/a	ADC input 1
P9_41	core_gpio[19] @ 0x41200000	161	GPIO
P9_42	core_pwm[0] @ 0x41000000	n/a	PWM_0:0
P9_43	n/a	n/a	GND
P9_44	n/a	n/a	GND
P9_45	n/a	n/a	GND
P9_46	n/a	n/a	GND