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TMS570LS1227: IOMM I/O loopback mechanism in safety manual

Benjamin Zhou
Expert 4000 points
Part Number: TMS570LS1227

Hi Team,

  As TMS570LS1227 safety manual IOMM I/O mentioned：

• Boot Time Software Test of Function Using I/O Loopback
• Periodic Software Test of Function Using I/O Loopback 

for the I/O loopback, Could you kindly share more information for the mechanism to realize this feature? is using the the internal connection IOMM  or should using external connection for write/read the I/O status?   

   What's the means of "Boot Time Software Test"? is it means in 1227 internal bootloader execute time-slot or customer side bootloader software code?   and what's the frequency for periodic software test and which prototype should called for the periodic software test of I/O loopback?

Expect for your reply, thanks.

Best Regards

Benjamin

  

  • 0
    TI__Guru**** 196836 points
    Hello Benjamin,

    There is no IOMM specific loopback test. This loopback diagnostic is listed under the section for IOMM. This is just listed in IOMM for completeness sake. Practically speaking, IOMM does not have any dedicated pin associated with it. If you are testing the respective peripheral pins that are associated to each peripheral (for example CAN loopback, SPI loopback, etc), you are fulfilling this diagnostic.

    At reset, I/O loopback is not enabled. SW needs to enable the analog loopback and execute the diagnostic.
  • 0 in reply to QJ Wang
    Prodigy 30 points

    hello QJ Wang

     what is  the analog loopback ? how to use the analog loopback ?

  • 0 in reply to tao hong
    TI__Guru**** 196836 points

    Hello Tao,

    The analog loopback is the loopback through the pin-level input and output buffers.

    In the following diagram (use SPI as example):

    The blue is the digital loopback path. The black line with yellow highlight is the analog loopback path through the TX pin buffers:

  • 0 in reply to QJ Wang
    TI__Guru**** 196836 points
    You can enable/disable the I/O analog loopback by setting/clearing the LPBK TYPE bit of IOLPBKSTCR (I/O-Loopback Test Control Register) register for SPI module.
  • 0 in reply to QJ Wang
    Prodigy 30 points

    Hi QJ Wang

    whether GPIO(General-Purpose Input/Output (GIO) Module) have I/O Loopback function?

    we don't find  Corresponding configuration register in GPIO Module chapter of datasheet.

    Safety Manual for TMS570LS12x mention :

    6.13 I/O Multiplexing Module (IOMM)
    The I/O multiplexing module (IOMM) provides software configurable mapping of internal module I/O
    functionality to device pins.
    The following tests can be applied as diagnostics for this module (to provide diagnostic coverage on a
    specific function):
    • Locking Mechanism For Control Registers
    • Master ID Filtering
    • Error Trapping
    • Periodic Software Readback of Static Configuration Registers
    • Boot Time Software Test of Function Using I/O Loopback
    • Periodic Software Test of Function Using I/O Loopback
    • Software Readback of Written Configuration
    The following tests can be applied as a test-for-diagnostic on this module, and could be used to meet
    Latent Fault Metric Requirements of ISO26262 (in combination with other diagnostics on the primary
    function):
    • Internal Watchdog
    • External Watchdog
    • CPU Lockstep Compare
    • Flash Data ECC
    • SRAM Data ECC

  • 0 in reply to tao hong
    TI__Guru**** 196836 points
    Hello Tao,

    For GIO, whenever you write a value (1 or 1) to DOUT register, you can read this value back from DIN register.