Venice Digital IO

The intent of this page is to provide information about Venice single board computers general purpose off-board digital IO signals.

DIO and Pin Function Mapping

Venice baseboards provide multiple digital IO signals to a connector. The IMX8MM has 5 GPIO blocks having 32 GPIO's each which typically get mapped to gpio 0 - through gpio 159 in the Linux kernel. Note that this mapping is not guaranteed to stay the same across kernel versions - you can look at the debugfs /sys/kernel/debug/gpio file to see where the IMX8MM GPIO controller is mapped.

The various Venice product hardware manuals contain a table of what pins on the Digital IO connector routes to what IMX8MM GPIO. In some cases these signals can be pinmux'd internally to other functions as indicated in the table.

See the operating manual "Specifications", "Electrical" section for information on DIO max and min driving strength.

Note on Termination

Most of the standard DIO lines below (labeled DIO0,DIO1,DIO2,etc) which are connected to the i.MX8M SoC:

• Operate on 3.3V logic
• Have a 332-ohm series resistor for limiting current.
• Have a 390 pF capacitor for debounce
• Have a ESD TVS Diode
• Have a 4.75k ohm pull up resistor to 3.3
• Have an internal weak pulldown at approximately 30-40k ohm.
• Exceptions:
  • GW71xx only has a series limiting resistor (no cap or TVS or pullup)

Please contact Gateworks support if more information is required about a specific SBC.

Venice DIO Mapping:

Board	Connector1	Primary Function2	IMX8MM_PAD	U-Boot3	Linux4	Notes
GW740x	J14.1	DIO0	GPIO1_9	GPIO1_IO9	dio0
	J14.2	DIO1	GPIO1_11	GPIO1_IO11	dio1
	J14.3	UART1_RX	input		/dev/ttymxc0	shared with GPS
	J14.4	UART1_TX	output		/dev/ttymxc0	shared with GPS
	J14.5	I2C4_SCL	output		/dev/i2c-3
	J14.6	I2C4_SDA	output		/dev/i2c-3
	J14.7	GSC_ADC1	input			Can measure 0 to 5V
	J14.8	GSC_ADC2	input			Can measure 0 to 5V
	J14.9	VDD_3P3
	J14.10	GND
GW730x	J9.1	DIO0	GPIO1_IO07	GPIO1_7	dio0
	J9.2	DIO1	GPIO1_IO09	GPIO1_9	dio1	can be ENET1_1588_EVENT0_OUT5
	J9.3	UART1_RX	GPIO5_IO24	GPIO5_24	managed by UART driver	shared with GPS RX
	J9.4	UART1_TX	GPIO5_IO23	GPIO5_23	managed by UART driver	shared with GPS TX
	J9.5 / J17.34	I2C3_SCL	I2C3_SCL	GPIO5_17	managed by I2C driver	shared with MIPI connector
	J9.6 / J17.36	I2C3_SDA	I2C3_SDA	GPIO5_19	managed by I2C driver	shared with MIPI connector
	J9.7	GSC_ADC1	-	vdd_adc1	vdd_adc1	Can measure 0 to 5V
	J9.8	GSC_ADC2	-	vdd_adc2	vdd_adc2	Can measure 0 to 5V
	J9.9	VDD_3P3	-	-	-
	J9.10	GND	-	-	-
	J17.43	MIPI_GPIO1	GPIO4_IO04	GPIO4_4	mipi_gpio1
	J17.45	MIPI_GPIO2	GPIO4_IO03	GPIO4_3	mipi_gpio2
	J17.47	MIPI_GPIO3	GPIO4_IO01	GPIO4_1	mipi_gpio3
	J17.48	MIPI_GPIO4	GPIO1_IO01	GPIO1_1	mipi_gpio4
	J14.22 / J12.22	PCI_WDIS#	SAI1_RXD5	GPIO4_7	pci_wdis#	set in U-Boot / Linux
	J14.20 / J12/20	PCI_RST#	SAI1_RXD4	GPIO4_6	managed by PCI driver
GW720x	J5.1	DIO0	GPIO1_IO07	GPIO1_7	dio0
	J5.2	DIO1	GPIO1_IO09	GPIO1_9	dio1	can be ENET1_1588_EVENT0_OUT5
	J5.3	UART1_RX	GPIO5_IO24	GPIO5_24	managed by UART driver	shared with GPS RX
	J5.4	UART1_TX	GPIO5_IO23	GPIO5_23	managed by UART driver	shared with GPS TX
	J5.5 / J4.34	I2C3_SCL	I2C3_SCL	GPIO5_17	managed by I2C driver	shared with MIPI connector
	J5.6 / J4.36	I2C3_SDA	I2C3_SDA	GPIO5_19	managed by I2C driver	shared with MIPI connector
	J5.7	GSC_ADC1	-	vdd_adc1	vdd_adc1	Can measure 0 to 5V
	J5.8	GSC_ADC2	-	vdd_adc2	vdd_adc2	Can measure 0 to 5V
	J5.9	VDD_3P3	-	-	-
	J5.10	GND	-	-	-
	J4.43	MIPI_GPIO1	GPIO4_IO04	GPIO4_4	mipi_gpio1
	J4.45	MIPI_GPIO2	GPIO4_IO03	GPIO4_3	mipi_gpio2
	J4.47	MIPI_GPIO3	GPIO4_IO01	GPIO4_1	mipi_gpio3
	J4.48	MIPI_GPIO4	GPIO1_IO01	GPIO1_1	mipi_gpio4
	J8.22 / J10.22	PCI_WDIS#	SAI1_RXD5	GPIO4_7	pci_wdis#	set in U-Boot / Linux
	J8.20 / J10/20	PCI_RST#	SAI1_RXD4	GPIO4_6	managed by PCI driver
GW710x	J4.1	VDD_5P0	-	-	-
	J4.2	GND	-	-	-
	J4.3	VDD_5P0	-	-	-
	J4.4	GND	-	-	-
	J4.5	VDD_3P3	-	-	-
	J4.6	GND	-	-	-
	J4.7	SPI_MOSI	ECSPI2_MOSI	GPIO5_11	managed by SPI driver	can be UART4_TX5
	J4.8	SPI_MISO	ECSPI2_MISO	GPIO5_12	managed by SPI driver
	J4.9	SPI_SCLK	ECSPI2_SCLK	GPIO5_10	managed by SPI driver	can be UART4_RX5
	J4.10	SPI_SS0	ECSPI2_SS0	GPIO5_13	managed by SPI driver
	J4.11	I2C3_SCL	I2C3_SCL	GPIO5_18	managed by I2C driver	can be PWM4_OUT5
	J4.12	I2C3_SDA	I2C3_SDA	GPIO5_19	managed by I2C driver	can be PWM3_OUT5
	J4.13	UART3_RX	UART3_RXD	GPIO5_26	managed by UART driver
	J4.14	UART3_TX	UART3_TXD	GPIO5_27	managed by UART driver
	J4.15	GSC_PB#	-	-	user_pb	Connect pushbutton to GND
	J4.16	GSC_ADC1	-	vdd_adc2	vdd_adc1	Can measure 0 to 5V
	J4.17	DIO0	GPIO1_IO07	GPIO1_7	dio0
	J4.18	DIO1	GPIO1_IO09	GPIO1_9	dio1	can be ENET1_1588_EVENT0_OUT5
	J4.19	DIO2	SAI1_RXD1	GPIO4_3	dio2
	J4.20	DIO3	SAI1_RXD2	GPIO4_4	dio3

1. This is the connector pinout.
2. This is the signal name from the ​Venice hardware manuals
3. This is the bank_pin name that can be used in U-Boot (see here)
4. This is the name provided to Linux via gpio-line-names in the device-tree (see here)
5. Any of the above pin function assignments can be altered by changing the device-tree to change the pinmux which is also where you can specify drive strength, pull-up, pull-down etc.

Note that all signals (unless noted in notes) are 3.3V tolerant.

Note that any GPIO can be used for the following:

• an additional SPI chip-select for those boards that have a SPI bus connector
• a 'bit-banged' PWM (using CPU timers)
• a 'bit-banged' I2C bus (using CPU timers)
• a 'bit-banged' MDIO bus (using CPU timers)

GPIO Mapping Table

Please see the generic Linux GPIO conversion here: gpio

Useful links

• Linux GPIO and GPIO basics
  • Linux GPIO usage
  • U-Boot GPIO usage
• Configuring PWM Hardware
• Linux I2C