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50 lines
2.1 KiB
Text
50 lines
2.1 KiB
Text
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mx6memcal - a tool for calibrating DDR on i.MX6 boards.
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The mx6memcal board isn't a real board, but a tool for use in bring-up of
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new i.MX6 board designs.
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It provides a similar function to the tool from NXP([1]) with a number
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of advantages:
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1. It's open-source, so it's easier to change if needed.
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Typical reasons for needing to change include the use of alternate
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UARTs and PMIC initialization.
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2. It produces an image that's directly loadable with imx_usb [2] or
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SB_LOADER.exe [3].
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The NXP tool requires either a cumbersome JTAG connection that
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makes running the DDR very slow or a working U-Boot image that
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suffers from a chicken-and-egg problem (i.e. where do you get the
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DDR parameters for U-Boot?).
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3. It doesn't prompt for parameters, so it's much faster to gather
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data from multiple boards.
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4. Parameters to the calibration process can be chosen through
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'make menuconfig'.
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When booted, the mx6memcal board will run the DDR calibration
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routines and display the result in a form suitable for cut and
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paste into struct mx6_mmdc_calibration. It can also optionally
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produce output in a form usable in a DCD-style .cfg file.
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Selections in Kconfig allow most system design settings to be chosen:
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1. The UART number and pad configuration for the UART. Options
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include support for the most frequent reference designs on
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i.MX6DQ/SDL (SABRE Lite and SABRESD designs).
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2. The memory bus width (64 and 32-bit)
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3. The number of chip-selects in use
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4. The type of DDR (DDR3 or LPDDR2). Note that LPDDR2 support
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is incomplete as of this writing.
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5. The type of DDR chips in use. This selection allows re-use of common
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parts and four DDR3 and two LPDDR2 parts are currently defined
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6. The On-die termination value for the DRAM lines
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7. The DRAM drive strength
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8. The RTT_NOM and RTT_WR termination settings
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9. RALAT/WALAT latency values
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References:
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[1] - NXP DDR Stress Test Tool - https://community.nxp.com/docs/DOC-105652
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[2] - Boundary Devices imx_usb_loader
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https://github.com/boundarydevices/imx_usb_loader
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[3] - Use of SB_Loader.exe
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https://boundarydevices.com/windows-users-and-unbricking
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