TIP
Unlike C300, the Series C I/O modules do not have an alphanumeric display for displaying
test codes.
Series C I/O modules run the following self-tests (transparent to the user) every time the module
boots up following a power-on, reset, or reboot.
l After the hardware and memory initializations AI, AO, and LLMUX IOMs reload the FPGA (fieldprogrammable gate array) image from the flash memory to the FPGA.
l All IOMs check the validity of the application image by computing the CRC (Cyclic Redundancy
Check) of the flash memory where application image is stored. If the CRC comparison is valid,
the module transfers to the application mode. Otherwise, the module stays in the boot mode
waiting for a firmware download operation.
l In the application mode hardware and memory is re-initialized for application operation and
module ID set by the address jumpers is checked.
Modules then execute a series of self-diagnostics as listed below (any failure-detected results
in hard fail of the IOM.)
o CPU: Checks the CPU registers by writing and reading back specific patterns and
execution of a set of logical operations.
o RAM contents: Test patterns are written and read back to all RAM locations. This test
ensures that each RAM bit can store and retrieve 0 and 1 without any error.
o Address lines: CPU address lines are tested by walking 1's and 0's. This test ensures
that each address lines can be changed independent of others.
o Flash contents: CRC of the application image is checked again.
o Stack: A test pattern is written to the top of the stack, which is confirmed read back.
This pattern is used for the background stack diagnostics during normal operation of
the module.
