241 lines
9.2 KiB
ReStructuredText
241 lines
9.2 KiB
ReStructuredText
.. _pico_pi_m4:
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Pico-Pi i.MX7D - Android Things IoT Development Platform
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#############################################################
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Overview
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********
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The i.MX7D SoC is a Hybrid multi-core processor composed of Single Cortex A7
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core and Single Cortex M4 core.
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Zephyr was ported to run on the M4 core. In a later release, it will also
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communicate with the A7 core (running Linux) via RPmsg.
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.. image:: ./pico_pi_m4.png
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:width: 470px
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:align: center
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:alt: Pico-Pi i.MX7D
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Hardware
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********
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The Pico-Pi Platform is composed of a CPU and IO board.
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Pico-Pi IO Board
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================
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- S1 - On/Off (MX7_ONOFF signal)
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- Board to board connector : Edison compatible connector (70 configurable pins)
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- mikroBUS expansion connector ADC, GPIO, I²C, PWM, SPI, UART)
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- 10-pin needle JTAG Connector
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- Debug USB exposing One UART
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- MIPI DSI 1 lane Connector
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- LCD Touch Connector
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- Audio Jack: Mic and Stereo Headphone
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Pico-Pi CPU Board
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=================
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- CPU i.MX7 Dual with a Single Cortex A7 (1 GHz) core and
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Single Cortex M4 (200MHz) core
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- Memory
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- RAM -> A7: 4GB
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- RAM -> M4: 3x32KB (TCML, TCMU, OCRAM_S), 1x128KB (OCRAM) and 1x256MB (DDR)
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- Flash -> A7: 8GB eMMC
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For more information about the i.MX7 SoC and Pico-Pi i.MX7D, see these references:
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- `i.MX 7 Series Website`_
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- `i.MX 7 Dual Datasheet`_
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- `i.MX 7 Dual Reference Manual`_
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Supported Features
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==================
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The Pico-Pi i.MX7D configuration supports the following hardware features on the
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Cortex M4 Core:
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+-----------+------------+-------------------------------------+
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| Interface | Controller | Driver/Component |
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+===========+============+=====================================+
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| NVIC | on-chip | nested vector interrupt controller |
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+-----------+------------+-------------------------------------+
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| SYSTICK | on-chip | systick |
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+-----------+------------+-------------------------------------+
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| GPIO | on-chip | gpio |
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+-----------+------------+-------------------------------------+
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| I2C | on-chip | i2c |
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+-----------+------------+-------------------------------------+
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| UART | on-chip | serial port-polling; |
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| | | serial port-interrupt |
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+-----------+------------+-------------------------------------+
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The default configuration can be found in the defconfig file:
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``boards/arm/pico_pi_m4/pico_pi_m4_defconfig``
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Other hardware features are not currently supported by the port.
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Connections and IOs
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===================
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The Pico-Pi board Board was tested with the following pinmux controller
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configuration.
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+---------------+---------------------+--------------------------------+
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| Board Name | SoC Name | Usage |
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+===============+=====================+================================+
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| UART_TX232 | UART1_TX | UART Console |
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+---------------+---------------------+--------------------------------+
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| UART_RX232 | UART1_RX | UART Console |
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+---------------+---------------------+--------------------------------+
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| RX_E | UART6_TX | UART (mikroBUS and Edison) |
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+---------------+---------------------+--------------------------------+
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| TX_E | UART6_RX | UART (mikroBUS and Edison) |
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+---------------+---------------------+--------------------------------+
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| I2CX_SDA_3V | I2C1_SDA | I2C (mikroBUS and Edison) |
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+---------------+---------------------+--------------------------------+
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| I2CX_SCL_3V | I2C1_SCL | I2C (mikroBUS and Edison) |
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+---------------+---------------------+--------------------------------+
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System Clock
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============
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The M4 Core is configured to run at a 200 MHz clock speed.
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Serial Port
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===========
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The iMX7D SoC has seven UARTs. The number 6 is configured for the console and
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the number 2 is used in the mikroBUS connector.
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Programming and Debugging
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*************************
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The Pico-Pi i.MX7D doesn't have QSPI flash for the M4 and it needs to be started by
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the A7 core. The A7 core is responsible to load the M4 binary application into
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the RAM, put the M4 in reset, set the M4 Program Counter and Stack Pointer, and
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get the M4 out of reset.
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The A7 can perform these steps at bootloader level or after the Linux system
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has booted.
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The M4 can use up to 5 different RAMs. These are the memory mapping for A7 and
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M4:
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+------------+-----------------------+------------------------+-----------------------+----------------------+
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| Region | Cortex-A7 | Cortex-M4 (System Bus) | Cortex-M4 (Code Bus) | Size |
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+============+=======================+========================+=======================+======================+
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| DDR | 0x80000000-0xFFFFFFFF | 0x80000000-0xDFFFFFFF | 0x10000000-0x1FFEFFFF | 2048MB (less for M4) |
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+------------+-----------------------+------------------------+-----------------------+----------------------+
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| OCRAM | 0x00900000-0x0091FFFF | 0x20200000-0x2021FFFF | 0x00900000-0x0091FFFF | 128KB |
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+------------+-----------------------+------------------------+-----------------------+----------------------+
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| TCMU | 0x00800000-0x00807FFF | 0x20000000-0x20007FFF | | 32KB |
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+------------+-----------------------+------------------------+-----------------------+----------------------+
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| TCML | 0x007F8000-0x007FFFFF | | 0x1FFF8000-0x1FFFFFFF | 32KB |
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+------------+-----------------------+------------------------+-----------------------+----------------------+
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| OCRAM_S | 0x00180000-0x00187FFF | 0x20180000-0x20187FFF | 0x00000000-0x00007FFF | 32KB |
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+------------+-----------------------+------------------------+-----------------------+----------------------+
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References
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==========
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- `i.MX 7 Dual Reference Manual`_ from page 182 (section 2.1.2 and 2.1.3)
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- `Toradex Wiki`_
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At compilation time you have to choose which RAM will be used. This
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configuration is done in the file ``boards/arm/pico_pi_m4/pico_pi_m4.dts`` with
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"zephyr,flash" (when CONFIG_XIP=y) and "zephyr,sram" properties. The available
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configurations are:
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.. code-block:: none
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"zephyr,flash"
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- &ddr_code
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- &tcml_code
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- &ocram_code
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- &ocram_s_code
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- &ocram_pxp_code
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- &ocram_epdc_code
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"zephyr,sram"
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- &ddr_sys
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- &tcmu_sys
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- &ocram_sys
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- &ocram_s_sys
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- &ocram_pxp_sys
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- &ocram_epdc_sys
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Below you will find the instructions to load and run Zephyr on M4 from A7 using
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u-boot.
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Connect both micro USB interfaces into the PC. This is the A7 console and the
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UART6 in the Edison connector is M4 console for Zephyr with both configured to work at 115200 8N1.
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The USB interface is used to power the CPU and IO boards and is connected
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to the USB OTG interface of the i.MX7D.
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After powering up the platform stop the u-boot execution on the A7 core and
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expose the eMMC as mass storage with the following command in the u-boot
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prompt: ``ums 0 mmc 0``. Copy the compiled zephyr.bin to the first FAT
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partition and remove the mounted device on the PC by issuing a "Ctrl+C" in the
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u-boot prompt.
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Set the u-boot environment variables and run the zephyr.bin from the
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appropriated memory configured in the Zephyr compilation:
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.. code-block:: console
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setenv bootm4 'fatload mmc 0:1 $m4addr $m4fw && dcache flush && bootaux $m4addr'
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# TCML
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setenv m4tcml 'setenv m4fw zephyr.bin; setenv m4addr 0x007F8000'
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setenv bootm4tcml 'run m4tcml && run bootm4'
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run bootm4tcml
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# TCMU
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setenv m4tcmu 'setenv m4fw zephyr.bin; setenv m4addr 0x00800000'
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setenv bootm4tcmu 'run m4tcmu && run bootm4'
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run bootm4tcmu
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# OCRAM
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setenv m4ocram 'setenv m4fw zephyr.bin; setenv m4addr 0x00900000'
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setenv bootm4ocram 'run m4ocram && run bootm4'
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run bootm4ocram
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# OCRAM_S
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setenv m4ocrams 'setenv m4fw zephyr.bin; setenv m4addr 0x00180000'
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setenv bootm4ocrams 'run m4ocrams && run bootm4'
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run bootm4ocrams
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# DDR
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setenv m4ddr 'setenv m4fw zephyr.bin; setenv m4addr 0x80000000'
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setenv bootm4ddr 'run m4ddr && run bootm4'
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run bootm4ddr
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:ref:`build_an_application` and :ref:`application_run` for more details).
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References
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==========
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- `Loading Code on Cortex-M4 from Linux for the i.MX 6SoloX and i.MX 7Dual/7Solo Application Processors`_
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- `J-Link iMX7D Instructions`_
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.. _i.MX 7 Series Website:
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https://www.nxp.com/products/processors-and-microcontrollers/applications-processors/i.mx-applications-processors/i.mx-7-processors:IMX7-SERIES?fsrch=1&sr=1&pageNum=1
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.. _i.MX 7 Dual Datasheet:
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https://www.nxp.com/docs/en/data-sheet/IMX7DCEC.pdf
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.. _i.MX 7 Dual Reference Manual:
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https://www.nxp.com/webapp/Download?colCode=IMX7DRM
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.. _J-Link Tools:
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https://www.segger.com/downloads/jlink/#J-LinkSoftwareAndDocumentationPack
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.. _NXP iMX7D Connect CortexM4.JLinkScript:
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https://wiki.segger.com/images/8/86/NXP_iMX7D_Connect_CortexM4.JLinkScript
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.. _Loading Code on Cortex-M4 from Linux for the i.MX 6SoloX and i.MX 7Dual/7Solo Application Processors:
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https://www.nxp.com/docs/en/application-note/AN5317.pdf
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.. _J-Link iMX7D Instructions:
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https://wiki.segger.com/IMX7D
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.. _Toradex Wiki:
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https://developer.toradex.com/knowledge-base/freertos-on-the-cortex-m4-of-a-colibri-imx7#Memory_areas
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