Support for EPDIY Hardware #77

Lukas-Heiligenbrunner · 2025-03-06T17:07:22Z

EPDIY is a open hardware project for epaper displays:
https://github.com/vroland/epdiy

I've ported your firmware to this platform.
I tried to be as non-intrusive as possible.
All of the changes are only compiled if you target the epdiy platformio target.
Display size + display type are configureable with an env variable.
Text rendering is still missing and I'll add this later.

I've used this for the last several weeks and it works great so far.
Please review my code. If you guys are not interested in this I'll continue it in a soft-fork. :)

And should i add documentation somewhere? ;)

I've emailed @ryanckulp if you guys are interested in porting this back.
Thanks for your time.
-Lukas

read height/width from bmp header

…mp header

…thout custom compile

don't require a flashing refresh when painting on white

Lukas-Heiligenbrunner · 2025-03-08T11:24:56Z

Sry, overlooked the var name change. should be fine now. :)

ryanckulp · 2025-03-11T01:11:02Z

thanks @Lukas-Heiligenbrunner ! i think we're OK folding this in, just wanna get a few other outstanding PRs merged first, push a new release, then can review this independently. adding some docs in the meantime would be nice, even if just a link to a Gist. we could add them to the official DIY docs: https://docs.usetrmnl.com/go/diy/introduction

furkanmustafa

I have made a basic review (just by reading code, I haven't tested anything, including my suggestions).

It seems to me that this PR achieves non-intrusion of defaults perfectly, when added, it would not break or change any current behavior with TRMNL devices. It can be merged as-is. ✔️

My (partly incomplete) suggestions point towards a direction of more generalization of arbitrary device support, with having TRMNL specifics as defaults everywhere possible.

And if possible, the following would be even better;

much less mentions of #ifdef EPDIY
use something like DEVICE_TYPE=EPDIY instead of EPDIY
use feature toggling instead, wherever possible, like #if PIN_INTERRUPT >= 0
- (and use PIN_INTERRUPT=-1 to disable it for a device configuration)
define even more system specifics as device configuration variables,
- like ADC_DIVIDER=64.000 (/128)*2) (and ADC_DIVIDER=91.2981 (/128)*1.402)) for EPDIY)
Allow downloading display native bpp images, and skip bpp conversion if the remote image is like that.

PS. My review itself might require a review.

furkanmustafa · 2025-07-29T05:37:39Z

src/display.cpp

+#ifdef EPDIY
+#else


Suggested change

#ifdef EPDIY

#else

#ifndef EPDIY

furkanmustafa · 2025-07-29T05:38:04Z

src/display.cpp

 {
    Log.info("%s [%d]: Goto Sleep...\r\n", __FILE__, __LINE__);
+#ifdef EPDIY
+     epd_poweroff();


Suggested change

epd_poweroff();

epd_poweroff();

furkanmustafa · 2025-07-29T05:38:21Z

src/display.cpp

    BlackImage = NULL;
+#endif
+    Log.info("%s [%d]: display\r\n", __FILE__, __LINE__);
+


Suggested change

furkanmustafa · 2025-07-29T05:51:10Z

src/bl.cpp

+#ifdef EPDIY
+// image buffer (62 bytes for metadata
+uint8_t buffer[((uint32_t) EPDIY_WIDTH * EPDIY_HEIGHT / 8) + 62];
+#else
 uint8_t buffer[48062];    // image buffer
+#endif


(does not need to be addressed in this PR, but could be a general improvement)

48062 could also be expanded into meaningful constant calculation,
and EPDIY specifics can be eliminated here that way.

eg;

Suggested change

#ifdef EPDIY

// image buffer (62 bytes for metadata

uint8_t buffer[((uint32_t) EPDIY_WIDTH * EPDIY_HEIGHT / 8) + 62];

#else

uint8_t buffer[48062]; // image buffer

#endif

// in build settings:

// TODO: define DISPLAY_WIDTH, DISPLAY_HEIGHT, DISPLAY_BPP with TRMNL defaults (800x480 1bpp)

// TODO: define IMAGE_BPP (default = DISPLAY_BPP)

// in `bl.h`:

// in bytes - 62 bytes - header; 48000 bytes - bitmap (480*800 1bpp) / 8

#define DISPLAY_BMP_IMAGE_SIZE (((uint32_t)DISPLAY_WIDTH * DISPLAY_HEIGHT * IMAGE_BPP / 8) + 62)

uint8_t buffer[DISPLAY_BMP_IMAGE_SIZE];

furkanmustafa · 2025-07-29T05:54:38Z

lib/trmnl/src/bmp.cpp

+#ifndef EPDIY
  if (width != 800 || height != 480 || bitsPerPixel != 1 || imageDataSize != 48000 || colorTableEntries != 2)
    return BMP_BAD_SIZE;
+#endif


Suggested change

#ifndef EPDIY

if (width != 800 || height != 480 || bitsPerPixel != 1 || imageDataSize != 48000 || colorTableEntries != 2)

return BMP_BAD_SIZE;

#endif

if (width != DISPLAY_WIDTH ||

height != DISPLAY_HEIGHT ||

bitsPerPixel != IMAGE_BPP ||

imageDataSize != (DISPLAY_WIDTH*DISPLAY_HEIGHT*IMAGE_BPP/8) ||

colorTableEntries != (1<<IMAGE_BPP))

return BMP_BAD_SIZE;

furkanmustafa · 2025-07-29T05:58:02Z

src/display.cpp

+#ifdef EPDIY
+void convert_1bit_to_4bit(const uint8_t *fb_1bit, uint8_t *fb_4bit, int width, int height) {
+    int byte_width = ((width + 31) / 32) * 4;  // Each byte in 1-bit framebuffer stores 8 pixels
+    int row_size_out = width / 2; // Each row in the 4-bit framebuffer (2 pixels per byte)
+
+    for (int y = 0; y < height; y++) {
+        int out_row_index = (height - 1 - y) * row_size_out; // Flip Y-axis
+
+        for (int x = 0; x < width; x += 2) {
+            int byte_index = (y * byte_width) + (x / 8);
+            int bit_index1 = 7 - (x % 8);
+            int bit_index2 = 7 - ((x + 1) % 8);
+
+            uint8_t pixel1 = (fb_1bit[byte_index] >> bit_index1) & 1;
+            uint8_t pixel2 = (fb_1bit[byte_index] >> bit_index2) & 1;
+
+            fb_4bit[out_row_index++] = (pixel1 ? 0x0F : 0x00) << 4 | (pixel2 ? 0x0F : 0x00);
+        }
+    }
 }
+#endif


Conditional is not necessary. Compiler would eliminate dead code if unused anyway.

Suggested change

#ifdef EPDIY

void convert_1bit_to_4bit(const uint8_t *fb_1bit, uint8_t *fb_4bit, int width, int height) {

int byte_width = ((width + 31) / 32) * 4; // Each byte in 1-bit framebuffer stores 8 pixels

int row_size_out = width / 2; // Each row in the 4-bit framebuffer (2 pixels per byte)

for (int y = 0; y < height; y++) {

int out_row_index = (height - 1 - y) * row_size_out; // Flip Y-axis

for (int x = 0; x < width; x += 2) {

int byte_index = (y * byte_width) + (x / 8);

int bit_index1 = 7 - (x % 8);

int bit_index2 = 7 - ((x + 1) % 8);

uint8_t pixel1 = (fb_1bit[byte_index] >> bit_index1) & 1;

uint8_t pixel2 = (fb_1bit[byte_index] >> bit_index2) & 1;

fb_4bit[out_row_index++] = (pixel1 ? 0x0F : 0x00) << 4 | (pixel2 ? 0x0F : 0x00);

}

}

}

#endif

void convert_1bit_to_4bit(const uint8_t *fb_1bit, uint8_t *fb_4bit, int width, int height) {

int byte_width = ((width + 31) / 32) * 4; // Each byte in 1-bit framebuffer stores 8 pixels

int row_size_out = width / 2; // Each row in the 4-bit framebuffer (2 pixels per byte)

for (int y = 0; y < height; y++) {

int out_row_index = (height - 1 - y) * row_size_out; // Flip Y-axis

for (int x = 0; x < width; x += 2) {

int byte_index = (y * byte_width) + (x / 8);

int bit_index1 = 7 - (x % 8);

int bit_index2 = 7 - ((x + 1) % 8);

uint8_t pixel1 = (fb_1bit[byte_index] >> bit_index1) & 1;

uint8_t pixel2 = (fb_1bit[byte_index] >> bit_index2) & 1;

fb_4bit[out_row_index++] = (pixel1 ? 0x0F : 0x00) << 4 | (pixel2 ? 0x0F : 0x00);

}

}

}

furkanmustafa · 2025-07-29T05:58:59Z

src/display.cpp

+    if(width == 0 || height == 0) {
+      width = 800;
+      height = 480;
+    }


Suggested change

if(width == 0 || height == 0) {

width = 800;

height = 480;

}

if(width_b == 0 || height_b == 0) {

width_b = width;

height_b = height;

}

furkanmustafa · 2025-07-29T06:04:36Z

src/display.cpp

+    uint16_t width = display_width();
+    uint16_t height = display_height();
+
+#ifdef EPDIY


Suggested change

#ifdef EPDIY

#if IMAGE_BPP == 1 && DISPLAY_BPP == 4

furkanmustafa · 2025-07-29T06:06:21Z

src/display.cpp

+    Log.info("%s [%d]: Paint_NewImage %s\r\n", __FILE__, __LINE__, _err);
+    delete[] image_buffer_4bpp;
+    epd_poweroff();
+#else


Suggested change

#else

#elseif IMAGE_BPP != DISPLAY_BPP

#error Unsupported display configuration for BPP conversion

#else

furkanmustafa · 2025-07-29T06:08:03Z

src/display.cpp

+#ifdef EPDIY
+#else


Suggested change

#ifdef EPDIY

#else

#ifndef EPDIY

Lukas-Heiligenbrunner and others added 12 commits February 11, 2025 23:00

add support for epdiy board with esp32s3

81eefbe

convert image to 4bit framebuffer before switching buffers

6c7946f

read height/width from bmp header

disable size check in bmp.cpp and determine data jump position from b…

e670db4

…mp header

Set API URL via Captive Portal Setup and allow http/https API URLs wi…

15f57e0

…thout custom compile

Don't save the default API URL, fall back to API_BASE_URL

138534a

allow larger images to be displayed

8af7c91

don't require a flashing refresh when painting on white

define device size and type as env variable

b618db1

add support for bat voltage readings

321ac04

Merge branch 'usetrmnl:main' into main

4539057

cleanup var names and ifdefs

2fd31d5

rename platformio env name to epdiy

5f51611

fix invalid var names for other targets

46dc2ec

yankobogdan requested a review from GoReNeY June 25, 2025 11:20

furkanmustafa approved these changes Jul 29, 2025

View reviewed changes

-#ifdef EPDIY
-// image buffer (62 bytes for metadata
-uint8_t buffer[((uint32_t) EPDIY_WIDTH * EPDIY_HEIGHT / 8) + 62];
-#else
-uint8_t buffer[48062];    // image buffer
-#endif
+// in build settings:
+// TODO: define DISPLAY_WIDTH, DISPLAY_HEIGHT, DISPLAY_BPP with TRMNL defaults (800x480 1bpp)
+// TODO: define IMAGE_BPP (default = DISPLAY_BPP)
+// in `bl.h`:
+// in bytes - 62 bytes - header; 48000 bytes - bitmap (480*800 1bpp) / 8
+#define DISPLAY_BMP_IMAGE_SIZE (((uint32_t)DISPLAY_WIDTH * DISPLAY_HEIGHT * IMAGE_BPP / 8) + 62)
+uint8_t buffer[DISPLAY_BMP_IMAGE_SIZE];

-#ifndef EPDIY
-  if (width != 800 || height != 480 || bitsPerPixel != 1 || imageDataSize != 48000 || colorTableEntries != 2)
-    return BMP_BAD_SIZE;
-#endif
+  if (width != DISPLAY_WIDTH ||
+      height != DISPLAY_HEIGHT ||
+      bitsPerPixel != IMAGE_BPP ||
+      imageDataSize != (DISPLAY_WIDTH*DISPLAY_HEIGHT*IMAGE_BPP/8) ||
+      colorTableEntries != (1<<IMAGE_BPP))
+    return BMP_BAD_SIZE;

-#else
+#elseif IMAGE_BPP != DISPLAY_BPP
+#error Unsupported display configuration for BPP conversion
+#else

Support for EPDIY Hardware #77

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Support for EPDIY Hardware #77

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Lukas-Heiligenbrunner commented Mar 6, 2025

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Lukas-Heiligenbrunner commented Mar 8, 2025

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ryanckulp commented Mar 11, 2025 •

edited

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