N64Digital `System`->`Debug / Self Test`

N64Digital's Self Test can help identifing issues with the flex install.

In order to perform a test for the audio signals (BCLK, LRCLK and SDATA) make sure you run a game outputting audio.

The Everdrive menu does not output any audio!

Clock Test

Clock Source

This is the clock source of the HDMI output. In normal operation, this shows CLKIN
Clock Input

An X here points to a problem with the VID_CLK connection.
PLL_A Lock

If you get an X here, N64Digital gets a clock signal, but the PLL cannot lock. This might be related to a weak/intermittent VID_CLK connection.
PLL_B Lock

PLL_B is connected to the N64Digital's onboard crystal oscillator.

The test accumulates data read from the FPGA and marks the pins according to this:

X signal always has the same value as it's adjacent pins (possible bridge to adjacent pin)
L signal value differs from it's adjacent pin, but is always low (possible bridge to ground)
H signal value differs from it's adjacent pin, but is always high (possible bridge to 3.3V)
❤️ signal does not match any of the above conditions -> good!

The test can be reset with controller button R. After a test reset, it's normal to see signals testing bad for some time.

Main-Flex

This shows the amount of lag introduced by N64Digital's scaler in milliseconds (ms)

The lag depends on the configuration of the Advanced Video->Frame Lock setting:

minimal (lowest lag) Output buffer (and therefore output lag) is calculated for lowest possible lag. It changes depending on the following settings:
- Output Resolution
- Scaler -> Zoom
- Scaler -> Vert. Adjust
- Scaler -> PAL Input Height
- Video Standard (PAL / NTSC)
normal Output buffer is calculated based on the highest possible lag for a given resolution. This prevents an output resync to occur, when setting different Zoom values.
off (triple buffered) you should see a lag value constantly changing as input and output frame rate are not locked.