Embedded module TQMa53 - PTXdist Linux BSP documentation

RS485 bus block in half-duplex mode
Affects RS485 via UARTx
Issue During i.MX53 reset the UARTx.CTS# pin is low by default (CPU internal pull down)
Effect Using the MBa53x RS485 circuitry in a half-duplex slave device or half-duplex multi-master environment may block the RS485 bus during i.MX53 reset.
The bus is released as soon as the UARTx.CTS# pin is properly configured by software (e.g. U-Boot, Linux, etc.)
Solution / Workaround Add a 10k pull up to the UARTx.CTS# signal on carrier board

  • Affected Hardware: TQMa53 Rev. 0400
  • Impact:
    eMMC drive strength (card to host) is too high in card default configuration. This degrades signal integrity and has the potential to decrease the lifetime
  • Solution:
    use only new linux / u-boot from BSP rev. 0108 or port the required changes to your bootloader / operating system.
  • Details:

    Starting with TQMa53 rev. 0400 a new eMMC type with better performance characteristics is used. This eMMC features a configurable drive strength (MMC CMD4 – SET_DSR, see JEDEC Standard No. 84-A441, Table 22)

    To keep signal integrity and prevent decreasing the lifetime of the processor the following configuration step for the eMMC must be implemented:

    • Write 0x0100 + 16 Stuff bits using CMD4 to the card everytime the card is selected using CMD7

    The current state of the changes needed in BSP Rev.0109 for:

    • u-boot 2013.01: all versions of the TQMa53 modifies device tree before booting linux to incorporate the correct dsr value for eMMC
    • linux 3.9 (TQMa53 + MBa53): value for dsr parsed from device tree property
    • linux 3.11 (TQMa53 + TBa53): value for dsr parsed from device tree property
    • barebox: 2012.07: (TQMa53 + MBa53): DSR support implemented, modifies device tree before booting linux to incorporate the correct dsr value for eMMC

    To boot linux from barebox or an older u-boot version, you need to modify device tree to forward the dsr information to the kernel. Add property “tq,dsr” to the node “/soc/aips@50000000/spba@50000000/esdhc@50020000” with u32 value 0x0100

    ATTENTION: the usage of SET_DSR is strongly encouraged for TQMa53 Rev. 0400.


  • Affected Revisions: 0102
  • Issue: DVI support works not as expected out of the box
  • Solution:
    1) BSP Revision 0103 fixes the issue. Update
    2) The files from this archive have to be copied to your BSP project. After the files are in the right place the following steps have to be executed:
    ptxdist menuconfig
    -> select "Enable DVI on startup"
    -> Exit
    -> Save Configuration
    ptxdist go
    ptxdist images
  • Affected Revisions: up to 0104
  • Issue: dd applet does not support all options (for instance conv=fsync)
  • Solution:
    1) update BSP
    2) configure busybox and recompile
    ptxdist menuconfig
    -> select "Shell an Console Tools"
    -> select "busybox"
    -> select "Coreutils"
    -> select "Enable ibs, obs and conv options"
    -> Exit
    -> Save Configuration
    ptxdist go
    ptxdist images
  • Affected Revisions: 0105
  • Issue: u-boot freezes when using command autocompletion
  • Solution: compile BSP only with configured toolchain
  • Affected Revisions: 0102 / 0103
  • Issue: sporadic timeout errors when writing update to eMMC / SD-Card
  • Solution:
    1) update Barebox. Barebox in BSP Revision 0104 fixes the issue
    2) try to repeat the failed update
  • Affected Revisions: up to 0104
  • Issue: Pixelclock not working as set up in device tree
  • Solution: i.MX53 needs to have the serialize clock and the pixel clock with a fixed divider
    Serializer clock is 7 x pixelclock for single channel LVDS (cf. table 8-5 of the i.MX53 Reference Manual), set up device tree accordingly or use newer BSP where kernel sets this automatically
  • Affected Revisions: up to 0104
  • Issue: USB Host loose devices if Ethernet in LAN9514 is active or external USB-to ethernet is used
  • Solution: update BSP
  • Affected Revisions: all
  • Issue: Audio chip SGTL5000 is not detected during boot up
  • Solution: The chip needs a clean power on reset. When booting via watchdog reset and switching / disabling the clock the chip locks sometimes. Under investigation.
  • Affected Revisions: all
  • Issue: only one SSI interface can be enabled and used
  • Solution: Limitation in device driver. Under investigation. please contact us
  • Affected Revisions: 0103 - 0104
  • Issue: no sound with linux 3.5 on an Rev. 0300 module
  • Solution: update BSP
  • Affected Revisions: 0105
  • Issue: no sound with linux 3.9 on an Rev. 0200 module
  • Affected Revisions: 0105
  • Issue: not all videos can be played smoothly
  • Solution: under investigation, see here for further explanation
  • Affected Revisions: all
  • Issue: LVDS shows wrong color mapping with 18Bit / SPWG configuration
  • Solution: patch prepared for next revision
  • Affected Revisions: 0105, others unknown
  • Issue: NULL pointer exceptions from MMC driver stack and kernel panic during power up
  • Solution: patch prepared for next revision


  • Issue: Toolchain compilation fails in install-libs due to empty variable SHAREDLIBV in host-zlib Makefile
  • Solution: Always use the same PTXdist version as the toolchain project to compile a toolchain. (You can install multiple PTXdist versions parallel. Good way is to setup a link to the PTXdist version to use in the project)
  • Issue When installing ptxdist 2012.12.0 configure script gives the error configure: error: we need at least GNU sed 4.x
  • Solution Version string of sed has been changed. To fix this overwrite line 3800 in the configure file with the following line :
SED_VERSION=`$SED --version 2>/dev/null | $SED -ne "1 s/.*GNU.*\s\([0-9\+\.]\+\).*/\1/p"`


If you have compiler / compilation errors please contact us using our web formular.

The following issues are known with OSELAS.Toolchains:

  • GCC version: 4.6.2: internal compiler error in package DirectFB (should be fixed in gcc 4.6.3)
  • Last modified: 2022/08/04 15:02