Waveform

[nicolamas]

Hi everyone, I recently started looking at EPD displays which are really fantastic, by chance I came across the very interesting EPDIY.
I started by looking at the source code but no matter how hard I try I can't understand how the implementation works to use the waveforms, because looking at the header files of the various displays, I thought I was faced with a LUT that accepts the temperature and as output the necessary duration of the +V or -V voltage to go from white to black or from black to white, in order to generate the right gray in a scale of 16.
Instead there are 3-dimensional arrays, in which the content is mostly 0x00
I'm completely confused!
I see:
`
typedef struct {
int phases;
const uint8_t* luts;
const int* phase_times;
} EpdWaveformPhases;

typedef struct {
uint8_t type;
uint8_t temp_ranges;
EpdWaveformPhases const** range_data;
} EpdWaveformMode;

typedef struct {
int min;
int max;
} EpdWaveformTempInterval;
typedef struct {
uint8_t num_modes;
uint8_t num_temp_ranges;
EpdWaveformMode const** mode_data;
EpdWaveformTempInterval const* temp_intervals;
} EpdWaveform;
`
Can someone explain to me how it works?
I would be enormously grateful!

[martinberlin]

I recommend you reading this Issue to understand waveforms better.
Most of the waveforms here where done adjusting the timings manually. Adding temperature support is contemplated but I'm not really sure if implemented by @vroland
I also will take a look at the code in the next weeks so I might tell more. But in that issue I referenced there is more valuable information than my lines here.

[nicolamas]

Hello Martin,
I will read the exchange of messages carefully!
Many Thanks,
Nicola

[martinberlin]

Additionally I've started writing a Wiki article about this. As soon as I research more, will add code snippets and examples there:

https://github.com/vroland/epdiy/wiki/How-pixels-are-driven-in-a-parallel-epaper-with-epdiy