© 2014 Digi International Inc.
8
ConnectCore 6 Linux BSP Reference Manual
The Freescale i.MX6 CPU has a documented errata ERR004512 whereby the maximum
performance of Gigabit ENET is limited to 400Mbps (total for Tx and Rx).
GPIO
The CPU has seven GPIO ports, six with 32 GPIOs and one with 14 GPIOs. GPIOs are multiplexed
with different functionalities of the chip. IOMUX of the pins is done at the device tree.
GPIO Device Tree binding is described at
Documentation/devicetree/bindings/gpio/fsl-imx-
gpio.txt
The GPIOs can be easily accessed from the sysfs. For information about how to manage the
GPIOs from sysfs, refer to the Linux kernel documentation at
Documentation/gpio.txt
.
The JSCCWMX53 development board contains two user LEDs and two user buttons that can be
used to test the GPIOs.
A sample application called
gpio_sysfs_test
is available and can be added to the rootfs by adding
“dey-examples” to the EXTRA_IMAGE_FEATURES of your
local.conf
or by adding “dey-
examples-gpio-sysfs” to IMAGE_INSTALL_append.
I2C
The CPU has three I2C ports. I2C2 is connected to the Dialog DA9063 PMIC and the Kinetis CPU
and cannot be used for other peripherals.
I2C3 is connected to the HDMI, LCD touch screen, camera, audio codec, and routed to the
Adapter board for additional peripheral connections on the development board.
I2C Device Tree binding is described at
Documentation/devicetree/bindings/i2c/i2c-imx.txt.
One-Time Programmable (OTP) Bits
The i.MX6 CPU contains several one-time programmable bits (also known as e-fuses).
The OTP bits can be read and programmed through the sysfs, under
/sys/fsl_otp
.
User LED1
User LED2
User Button 1
User Button 2
Port pin
GPIO2_2 GPIO2_3
GPIO2_4
GPIO2_5
Linux gpio #
34
35
36
37
WARNING:
Programming the OTP bits is an irreversible operation that could
potentially brick your module. Please don’t program the OTP bits unless you are
sure of what you are doing
