[Cryptech Tech] FMC Arbiter

[Павел Шатов]

On 31.08.2015 0:36, Павел Шатов wrote:
>>>> Demo program for STM32 keeps writing "random" stuff in FPGA, reading it
>>>> back and comparing. As long as everything is fine, green LED should be
>>>> on and yellow LED will blink after every batch of tests. In case of
>>>> readback mismatch, red LED will be turned on.
>>
>> I haven't seen the red light at all yet, but the status indicated by the
>> steady green + blinking yellow is a bit unclear to me. That seems to
>> be what
>> happens both with the Novena FMC bitstream running, but also with the
>> dev-
>> bridge unconnected? Just a slightly different frequency?
>
> Hmmm, the green light is turned on at the very beginning, the yellow
> light toggles after every 100000 rounds of testing or so. It blinks to
> indicate, that the board is alive and doing something. The red light
> should be turned on as soon as mismatch in read back data is detected.
> When dev-bridge is unconnected, the red light should be turned on
> immediately. I will investigate.

Oops, Fredrik, you need to uncomment breaks in the main loop, I 
occasionally forgot to enable them.

Change
if (test_ok < TEST_NUM_ROUNDS) /*break*/;
to
if (test_ok < TEST_NUM_ROUNDS) break;

If you've taken a look at the demo program, you've most probably seen, 
that the main loop repeatedly calls test_fpga_data_bus() and then 
test_fpga_address_bus(). Each of these test functions runs many rounds 
of testing and then returns number of successfully passed tests. Main 
loop checks, whether these numbers are smaller, than TEST_NUM_ROUNDS. If 
that is true, then there was an error, so main loop breaks and red light 
turns on.

> --
> With best regards,
> Pavel Shatov