MIP405T Frequently Asked Questions

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Question #227: I have bricked my board by accidentally overwriting the U-Boot bootloader. How can I resurrect the board?
Answer: Do you have access to a JTAG debugger or an external EPROM programmer and a 4Mbit (or larger) EPROM suitable for the MPS on the board?
If not, please send the board back to MPL for repair.
If yes, the odds are good that you can fix the problem yourself.

  • Download the "img" version of the U-Boot binary from the MPL homepage.
  • Remove the U-Boot header and decompress the file as follows:
    • dd if=u-boot.img of=u-boot.bin.gz skip=64 bs=1
    • gunzip u-boot.bin.gz
  • The result should be a file called "u-boot.bin" with a file size of 524288 bytes.
MPS way (PIP405/MIP405 only):
  1. Program the EPROM with the content of the "u-boot.bin" file using the external EPROM programmer. If the EPROM size is larger than 4Mbit, remember to align the binary to the top of the EPROM address space.
  2. Insert the EPROM into the MPS of the board.
  3. Select the correct EPROM type and enable "Boot from MPS" mode by setting the DIP switches accordingly. Please check the "External Bootloader" chapter of the "User Manual" for details.
  4. Power-up the board, the board should start up normally.
  5. Download and program the U-Boot code into the on-board flash like this:
    • tftpb 400000 u-boot.img
    • mip405 flash mem
  6. Remove the power.
  7. Set the DIP switches back to "Boot from Boot Flash" mode.
  8. Remove the EPROM from the MPS.
  9. Re-apply the power, the board should start up normally.

JTAG way:
As there are many different JTAG debuggers (with many different features) available and the precise way of reprogramming the on-board flash is highly debugger specific, no detailed "step-by-step" instructions can be given, only a rough sketch of what needs to be done. Please see your JTAG debugger's manual for more details regarding the points listed below:
  • Make sure the communication between JTAG debugger and board is working reliable.
  • Configure the JTAG debugger to enable a data path from the CPU to the on-board flash (CS0, 4MB@0xFFC00000, r/w, 16bit width) and to select/use the proper flash type.
  • Make sure the on-board flash is properly "unlocked".
  • Program the on-board flash with the content of the raw "u-boot.bin" file @0xFFF80000.

Question #340: I observe power-up problems or sudden, unmotivated resets of the MIP board during normal operation. It seems to get worse if an additional add-on card is installed and/or the CPU and/or GPU load is increased.
Answer: Chances are that this is a power supply problem. In contrast to the PIP boards, the MIP boards expect their 5V system input voltage to be provided in a "suitable, clean" form, especially relating to short power transients. Please check the following points:

  • make sure there is a low impedance connection between the external power supply and the MIP board (wire length as short as possible / wire cross section as wide as possible).
  • supply 5.25V  instead of 5V to the system.
  • use a better power supply.
  • solder the power supply wires directly to the pads of the power supply connector on the MIP board.

Question #329: I have attached a PC/104 or PC/104-Plus card to the [PIP | MIP] and I am sure that the card is configured correctly both from the hardware and the software side. Nevertheless the card does not work as expected, but shows erratic behaviour.
Answer: Does the card need +12V, -12V or -5V from the PC104/PC104-Plus bus? If the answer is yes, chances are that the I/O drivers and/or some A/D or D/A circuitry are not properly powered.
By default the [PIP | MIP] does NOT provide the voltages mentioned above on the PC/104 or PC/104-Plus bus.
Please check the corresponding "User Manual" and/or "Technical Reference Manual" for details.

Question #285: Under Linux, I would like to use a card and/or driver using ISA interrupts, but it doesn't seem to work. Is there anything special about ISA interrupts?
Answer: As the [PIP405 | MIP405 | MIP405T] supports more than 16 interrupt sources, the ISA interrupts are remapped to a non PC-like position as described in the table below:

PPC405 Interrupt Number
0 - 24
used by PPC405 internal devices
interrupt from PIIX4 (Master PIC)
interrupt from DUART ([PIP405 | MIP405]) / unused (MIP405T)
external IRQ2
28 - 31
32 - 47
standard PC ISA interrupts

So, if you want to use ISA IRQ5 for example, you have to request interrupt 37 (32 + 5) in your driver.
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