incomplete sleep sequence causes Vcc shortcut and resets

[qrti]

Arduino Library for Color 2.9 inch e-paper b & c

displays of other sizes and platforms might be concerned as well

original in epd2in9.cpp

void Epd::Sleep() {
  SendCommand(DEEP_SLEEP);
  SendData(0xa5);
}

result

• the display reaches deep sleep but without switching off power beforehand as prescribed,
  the gate of the hat's charge pump MOSFET might be left in an unusable state,
  overriding the gate pulldown and shortcut Vcc, this also might reset the Arduino

proposal

1. change in epd2in9.cpp

void Epd::Sleep()
{
    SendCommand(VCOM_AND_DATA_INTERVAL_SETTING);
    SendData(0xF7);                         // set border floating VDB 1:0 = 11

    SendCommand(POWER_OFF);                 // power off

    SendCommand(DEEP_SLEEP);                // deep sleep
    SendData(0xa5);

    pinMode(CS_PIN, INPUT);                 // prevent parasitic supply
    pinMode(RST_PIN, INPUT);
    pinMode(DC_PIN, INPUT);

    SpiEnd();                               // optional
}

2. add to epdif.cpp (optional)

void EpdIf::SpiEnd(void)
{
    SPI.end();
}

3. add to epdif.h (optional)

static void SpiEnd(void);

I've done a lot of research, reading, testing, measuring to make these displays run as intended

[waveshare]

I will fix this