AMEPD Active Matrix Electrophoretic Display, active matrix electrophoretic display.

It is the screen of electronic paper books, and the debugging effect is similar to that of my Kindle.

screen parameters

Screen IC is SSD1680

122*250, single bit control, 1 is white, 0 is black

Progressive refresh, one byte 8bit, control horizontal 8 pixels

Built-in temperature sensor (IIC interface, not used this time)

Built-in OTP (10Byte, not used this time)

The screen controller is On-Chip package

SPI rate setting 4M is enough

Show Effect Features

The refresh rate is low, and the data is updated in seconds

Updating a piece of data alone may cause afterimages.

Update the entire screen data, there will be a lot of flickering fluctuations

Power failure, hardware reset, and software reset will not affect the display, but the configuration needs to be re-sent until the next time new display data is written.

Debugging Notes

The logic communication voltage 2 of the whole screen is 3.3v.

spi is mode 0, clk is idle low, sampled on the first rising edge

BSI pin: configured as 3-wire 9data SPI (H) or 4-wire SPI communication mode (L) by pulling high and low

CS chip select pin: low effective, can be read and written when pulled low

DC pin: data/command indication pin. (L, command; H, write data)

BUSY pin: When the screen IC refreshes data or resets, it outputs high: it does not respond to external read and write operations at this time. Pay special attention to this in the reading and writing logic of the screen. (idle low, busy high)

RST pin: low level reset, keep high during operation

VGL, VGH pins: the bias voltage required for the screen to flip the liquid crystal particles, software configurable, 16-20v. Through its own GDR and RESE and peripheral circuits, it forms a boost circuit

SPI communication timing

4-Wire SPI

3-Wire 9Bit SPI

code demo

register configuration

static void my_amepd_RegInit(void)
{
    AMEPD_SSD1680_WriteCmd(0x12);  // SW Reset
    my_sleep(20);
    my_amepd_ReadBusy();          // wait busy
    my_test_cli_echo("my_amepd_RegInit 0x12 \r\n");

    AMEPD_SSD1680_WriteCmd(0x01);
    AMEPD_SSD1680_WriteData(0xF9);
    AMEPD_SSD1680_WriteData(0x00);
    AMEPD_SSD1680_WriteData(0x00);

    AMEPD_SSD1680_WriteCmd(0x11);  // data enter mode
    AMEPD_SSD1680_WriteData(0x01);

    AMEPD_SSD1680_WriteCmd(0x44);  // set RAM x address
    AMEPD_SSD1680_WriteData(0x00); // set x start, range: 0-15
    AMEPD_SSD1680_WriteData(0x0F); // set x end

    AMEPD_SSD1680_WriteCmd(0x45);  // set RAM y address
    AMEPD_SSD1680_WriteData(0xF9); // RAM y address start, range: 0-249
    AMEPD_SSD1680_WriteData(0x00);
    AMEPD_SSD1680_WriteData(0x00); // RAM y address end
    AMEPD_SSD1680_WriteData(0x00);

    AMEPD_SSD1680_WriteCmd(0x3C);  // Border
    AMEPD_SSD1680_WriteData(0x05);

    AMEPD_SSD1680_WriteCmd(0x21);  // Display update control
    AMEPD_SSD1680_WriteData(0x00);
    AMEPD_SSD1680_WriteData(0x80); // S8-S167 for 1675 type panel

    // use internal temperature sernsor
    AMEPD_SSD1680_WriteCmd(0x18);
    AMEPD_SSD1680_WriteData(0x80);

    my_amepd_ReadBusy();          // wait busy
    my_test_cli_echo("my_amepd_RegInit 0x18 \r\n");
}

set display coordinates

static void my_amepd_SetPosition(int x_start, int x_end, int y_start, int y_end)
{
    my_test_cli_echo("%d \r\n", x_start);
    my_test_cli_echo("%d \r\n", x_end);
    my_test_cli_echo("%d \r\n", y_start);
    my_test_cli_echo("%d \r\n", y_end);

    my_amepd_RegInit();
    my_test_cli_echo("my_amepd_SetPosition X \r\n");

    AMEPD_SSD1680_WriteCmd(0x44);
    AMEPD_SSD1680_WriteData(x_start);
    AMEPD_SSD1680_WriteData(x_end);

    AMEPD_SSD1680_WriteCmd(0x45);
    AMEPD_SSD1680_WriteData(y_start);
    AMEPD_SSD1680_WriteData(0x00);
    AMEPD_SSD1680_WriteData(y_end);
    AMEPD_SSD1680_WriteData(0x00);

    AMEPD_SSD1680_WriteCmd(0x4E);
    AMEPD_SSD1680_WriteData(x_start);

    AMEPD_SSD1680_WriteCmd(0x4F);
    AMEPD_SSD1680_WriteData(y_start);
    AMEPD_SSD1680_WriteData(0x00);
    AMEPD_SSD1680_WriteCmd(0x24);
}

send display data

    for(col=0; col<max_col; col++) // send 122x250bits ram 2D13
    {
        for(row=0; row<max_row; row++)
        {
            AMEPD_SSD1680_WriteData(Image_demo[pcnt]);
            pcnt++;
        }
    }

update display data

    // 在发送显示数据之后调用
    AMEPD_SSD1680_WriteCmd(0x22);
    AMEPD_SSD1680_WriteData(0xF7);
    AMEPD_SSD1680_WriteCmd(0x20);

X/Y axis mirror display

You can set the start and end addresses of the RAMX and Y axes to make the display effect mirror X, mirror Y, or mirror X and Y together.

normal refresh

    AMEPD_SSD1680_WriteCmd(0x44);
    AMEPD_SSD1680_WriteData(0);  // x start
    AMEPD_SSD1680_WriteData(15); // x end

    AMEPD_SSD1680_WriteCmd(0x45);
    AMEPD_SSD1680_WriteData(0);  // y start
    AMEPD_SSD1680_WriteData(0x00);
    AMEPD_SSD1680_WriteData(249); // y end
    AMEPD_SSD1680_WriteData(0x00);

X-axis mirror display

    AMEPD_SSD1680_WriteCmd(0x44);
    AMEPD_SSD1680_WriteData(16);  // x start
    AMEPD_SSD1680_WriteData(10); // x end

    AMEPD_SSD1680_WriteCmd(0x45);
    AMEPD_SSD1680_WriteData(0);  // y start
    AMEPD_SSD1680_WriteData(0x00);
    AMEPD_SSD1680_WriteData(249); // y end
    AMEPD_SSD1680_WriteData(0x00);

Y-axis mirror display

    AMEPD_SSD1680_WriteCmd(0x44);
    AMEPD_SSD1680_WriteData(0);  // x start
    AMEPD_SSD1680_WriteData(15); // x end

    AMEPD_SSD1680_WriteCmd(0x45);
    AMEPD_SSD1680_WriteData(249);  // y start
    AMEPD_SSD1680_WriteData(0x00);
    AMEPD_SSD1680_WriteData(0); // y end
    AMEPD_SSD1680_WriteData(0x00);

XY axis mirroring is the same

The dead are like gentlemen, day and night

AMEPD SSD1680 debug record