XFM2: Testing your build

ByRené Ceballos

To assist with debugging XFM2 builds, I have created the following test binary files. They all have to be loaded using Adept, as described in the main XFM2 page.

tests_blinky.bit

Can be run either in a bare CMOD A7 board, or in a complete build.
Upon loading the file, the CMOD board will:

  • Blink the two green LEDs in alternation
  • Blink the tricolor LED in the sequence: red -> blue -> green
  • Flash the UART LED.
  • Send the text “XFM2” to the USB serial port, at low speed (115200, 8, N, 1).

This test tells you :

  • The FPGA board is healthy
  • If the sequence is smooth, the device is not restarting spuriously (signs of bad USB cable, or insufficient USB power).
  • If the text appears in the Terminal application, the serial communication is OK from the XFM2 (the other way around is not tested).
test_memory.bit

This test verifies that the EEPROM memory is properly connected to the CMOD A7.
After loading the test, check at the LD0 led color:

Green = Memory OK (write-then-read test passed)
Red + Blue = Unable to write memory (this is the result with a bare CMOD board)
Red + LD1/LD2 green = Unable to read memory
Red = Memory written and read properly, value doesn’t match (probably a too-slow memory)

test_audio.bit

This test file turns XFM2 into an audio generator. Using the buttons BTN0 and BTN1, a series of audio tones are produced and sent to the SPDIF and I2S outs. This is very helpful when testing the DAC board connections, SPDIF out and measuring and verifying S/N ratio, distortion, channel separation and frequency response.

Tests are selected with subsequent pushes of BTN0, as follows:

0 (initial state): Two-channel single impulse, triggered by BTN1 (ideal to test delay/reverbs).
1: Left channel only single impulse, triggered by BTN1.
2: White noise
3: Frequency sweep, DC to 24kHz
4: 16 Hz tone
5: 31 Hz tone
6: 63 Hz tone
7: 125 Hz tone
8: 250 Hz tone
9: 500 Hz tone
10: 1 kHz tone
11: 2kHz tone
12: 4kHz tone
13: 8kHz tone
14: 16kHz tone

For all continuous sound tests (#2 to #14) BTN1 will select between both channels, left channel or right channel. The audio activity led (green) will indicate the produced sound.

MIDIScope and MIDI indicator led (blue) is also operational during this test.

spectral.PNG

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