Added support for Waveshare 3color 7.5inch display by SBajonczak · Pull Request #272 · usetrmnl/trmnl-firmware

SBajonczak · 2026-01-09T20:41:49Z

As I mentioned I got hte problem with ghosting and scanlines in using the waveshare 7.5inch Display.

I figured out that theacutal implementation is only suitable for the B/W variant and not for the three colors variant.

I added the missing start sequence in this PR to support the three colors waveshare display.

Referencing this issue for the initial bug: #270

Copilot

Pull request overview

This pull request adds support for the Waveshare 3-color 7.5inch e-paper display to fix ghosting and scanlines issues experienced with the 3-color variant. The changes introduce new initialization sequences for the SSD1675B controller chip and modify display handling logic.

Key changes:

Adds new panel type WAVESHARE_3COLOR_800x480 with SSD1675B-specific initialization sequences
Modifies display refresh logic to force full refresh for 3-color SSD16xx displays
Includes extensive formatting changes and unrelated modifications to bl.cpp

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 19 comments.

File	Description
src/display.cpp	Changes global display type to WAVESHARE_3COLOR_800x480 and adds hardcoded refresh behavior overrides
src/bl.cpp	Contains formatting changes, NTP server change to IP addresses, and GPIO wakeup logic modifications
lib/bb_epaper/src/bb_epaper.h	Adds WAVESHARE_3COLOR_800x480 enum value and new public method declaration
lib/bb_epaper/src/bb_ep.inl	Adds SSD1675B initialization sequences, new panel definition, and conditional refresh logic

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Copilot · 2026-01-09T20:55:22Z

    if (!bWait) iRefreshMode = REFRESH_PARTIAL; // fast update when showing loading screen
+
+
+    iRefreshMode =REFRESH_FULL;


The refresh mode is being hardcoded to REFRESH_FULL, which overrides all the logic above that carefully determines the appropriate refresh mode based on conditions (lines 986-1001). This negates the benefits of fast and partial refresh modes. If the 3-color display requires full refresh, this should be handled conditionally based on the panel type rather than forcing it for all displays.

Suggested change

iRefreshMode =REFRESH_FULL;

Copilot · 2026-01-09T20:55:22Z

    {EP75_800x480, EP75_800x480_4GRAY_V2}, // b = darker grays
 };
-BBEPAPER bbep(EP75_800x480);
+BBEPAPER bbep(WAVESHARE_3COLOR_800x480);


The global display type is being changed from EP75_800x480 to WAVESHARE_3COLOR_800x480 which affects all users of this firmware, not just those with the 3-color display. This should be determined at runtime based on configuration or auto-detection, rather than being hardcoded.

Suggested change

BBEPAPER bbep(WAVESHARE_3COLOR_800x480);

BBEPAPER bbep(EP75_800x480);

Copilot · 2026-01-09T20:55:23Z

+// Minimaler SSD1675B (B/W/R) Init-Template für 800x480
+const uint8_t epd75r_ssd1675b_init_sequence_full[] PROGMEM = {
+    0x01, 0x12,            // SWRESET
+    BUSY_WAIT,
+    // Power Setting (Werte laut PDF/Modul)
+    0x06, 0x01, 0x07, 0x07, 0x3f, 0x3f, 0x03,
+    0x01, 0x04,            // Power on
+    BUSY_WAIT,
+    0x02, 0x11, 0x03,      // Data entry mode (Inkrement, Bitrichtung)
+    // RAM window
+    0x03, 0x44, 0x00, 0x0F,      // X start/end (Bytes für 800px → 0..0x0F)
+    0x05, 0x45, 0x00, 0x00, 0xDF, 0x01, // Y start/end (0..479 → 0x01DF)
+    0x02, 0x4E, 0x00,      // RAM X counter
+    0x03, 0x4F, 0x00, 0x00,// RAM Y counter
+    // Panel/Resolution/VCOM/Data Interval
+    0x05, 0x61, 0x03, 0x20, 0x01, 0xE0, // 800x480
+    0x03, 0x50, 0x11, 0x07, // VCOM & data interval (anpassen)
+    0x02, 0x3C, 0x80,       // Border (optional)
+    0x00
+};
+// // Schnelle Initialisierung (Fast) – vor dem Refresh ausgeführt
+// // Hinweis: Tri-Color-EPDs unterstützen „Fast“ nur sehr eingeschränkt. Diese Sequenz
+// // setzt die wesentlichen Register für einen schnelleren Update, ohne eigene LUTs.
+// const uint8_t epd75r_ssd1675b_init_sequence_fast[] PROGMEM = {
+//     0x01, 0x12,                          // SWRESET
+//     BUSY_WAIT,
+
+//     0x02, 0x11, 0x03,                    // Data Entry Mode
+
+//     // RAM-Fenster


Comments in the code are written in German (e.g., "Minimaler SSD1675B", "Werte laut PDF/Modul", "Schnelle Initialisierung"). For maintainability and accessibility to the broader development community, code comments should be in English, consistent with the rest of the codebase.

Suggested change

// Minimaler SSD1675B (B/W/R) Init-Template für 800x480

const uint8_t epd75r_ssd1675b_init_sequence_full[] PROGMEM = {

0x01, 0x12, // SWRESET

BUSY_WAIT,

// Power Setting (Werte laut PDF/Modul)

0x06, 0x01, 0x07, 0x07, 0x3f, 0x3f, 0x03,

0x01, 0x04, // Power on

BUSY_WAIT,

0x02, 0x11, 0x03, // Data entry mode (Inkrement, Bitrichtung)

// RAM window

0x03, 0x44, 0x00, 0x0F, // X start/end (Bytes für 800px → 0..0x0F)

0x05, 0x45, 0x00, 0x00, 0xDF, 0x01, // Y start/end (0..479 → 0x01DF)

0x02, 0x4E, 0x00, // RAM X counter

0x03, 0x4F, 0x00, 0x00,// RAM Y counter

// Panel/Resolution/VCOM/Data Interval

0x05, 0x61, 0x03, 0x20, 0x01, 0xE0, // 800x480

0x03, 0x50, 0x11, 0x07, // VCOM & data interval (anpassen)

0x02, 0x3C, 0x80, // Border (optional)

0x00

};

// // Schnelle Initialisierung (Fast) – vor dem Refresh ausgeführt

// // Hinweis: Tri-Color-EPDs unterstützen „Fast“ nur sehr eingeschränkt. Diese Sequenz

// // setzt die wesentlichen Register für einen schnelleren Update, ohne eigene LUTs.

// const uint8_t epd75r_ssd1675b_init_sequence_fast[] PROGMEM = {

// 0x01, 0x12, // SWRESET

// BUSY_WAIT,

// 0x02, 0x11, 0x03, // Data Entry Mode

// // RAM-Fenster

// Minimal SSD1675B (B/W/R) init template for 800x480

const uint8_t epd75r_ssd1675b_init_sequence_full[] PROGMEM = {

0x01, 0x12, // SWRESET

BUSY_WAIT,

// Power setting (values from datasheet/module)

0x06, 0x01, 0x07, 0x07, 0x3f, 0x3f, 0x03,

0x01, 0x04, // Power on

BUSY_WAIT,

0x02, 0x11, 0x03, // Data entry mode (increment, bit order)

// RAM window

0x03, 0x44, 0x00, 0x0F, // X start/end (bytes for 800px → 0..0x0F)

0x05, 0x45, 0x00, 0x00, 0xDF, 0x01, // Y start/end (0..479 → 0x01DF)

0x02, 0x4E, 0x00, // RAM X counter

0x03, 0x4F, 0x00, 0x00,// RAM Y counter

// Panel/resolution/VCOM/data interval

0x05, 0x61, 0x03, 0x20, 0x01, 0xE0, // 800x480

0x03, 0x50, 0x11, 0x07, // VCOM & data interval (adjust if needed)

0x02, 0x3C, 0x80, // Border (optional)

0x00

};

// // Fast initialization – executed before the refresh

// // Note: tri-color EPDs support "fast" mode only in a very limited way. This sequence

// // configures the essential registers for a faster update without custom LUTs.

// const uint8_t epd75r_ssd1675b_init_sequence_fast[] PROGMEM = {

// 0x01, 0x12, // SWRESET

// BUSY_WAIT,

// 0x02, 0x11, 0x03, // Data entry mode

// // RAM window

Copilot · 2026-01-09T20:55:23Z

+// // Schnelle Initialisierung (Fast) – vor dem Refresh ausgeführt
+// // Hinweis: Tri-Color-EPDs unterstützen „Fast“ nur sehr eingeschränkt. Diese Sequenz
+// // setzt die wesentlichen Register für einen schnelleren Update, ohne eigene LUTs.
+// const uint8_t epd75r_ssd1675b_init_sequence_fast[] PROGMEM = {
+//     0x01, 0x12,                          // SWRESET
+//     BUSY_WAIT,
+
+//     0x02, 0x11, 0x03,                    // Data Entry Mode
+
+//     // RAM-Fenster
+//     0x03, 0x44, 0x00, 0x63,              // RAM X start/end (0..99)
+//     0x05, 0x45, 0x00, 0x00, 0xDF, 0x01,  // RAM Y start/end (0..479)
+
+//     // RAM Counter
+//     0x02, 0x4E, 0x00,                    // RAM X counter
+//     0x03, 0x4F, 0x00, 0x00,              // RAM Y counter
+
+//     // Auflösung & Anzeigeparameter (ggf. für schnellere Intervalle anpassen)
+//     0x05, 0x61, 0x03, 0x20, 0x01, 0xE0,  // 800x480
+//     0x03, 0x50, 0x11, 0x07,              // VCOM & Data Interval (schnellere Intervalle je nach Spez.)
+//     0x02, 0x3C, 0x80,                    // Border
+
+//     0x00
+// };


Comments in the code are written in German (e.g., "Schnelle Initialisierung (Fast)", "vor dem Refresh ausgeführt", "Tri-Color-EPDs unterstützen"). For maintainability and accessibility to the broader development community, code comments should be in English, consistent with the rest of the codebase.

Copilot · 2026-01-09T20:55:26Z

@@ -426,6 +429,7 @@ class BBEPAPER
 {
  public:
    BBEPAPER(int iPanel);


The new public method bbepPrepareImageSSD1675B is added to the BBEPAPER class but is never called in the codebase. If this is intended as a utility function for future use or external callers, it should be documented. Otherwise, if it's not needed, it should be removed to avoid confusion.

Suggested change

BBEPAPER(int iPanel);

BBEPAPER(int iPanel);

// Utility method for advanced/external callers to prepare the image buffer

// for SSD1675B-based panels. This function is not invoked internally by

// the library but is exposed for applications that need fine-grained

// control over image preparation.

Copilot · 2026-01-09T20:55:26Z

+        memset(bbep.getBuffer(), 0xFF, 48000);
+        bbep.writePlane(PLANE_1);
+        Log_info("Image written to EPD buffer PLANE_1");
        iRefreshMode = REFRESH_PARTIAL;
 #endif
        iUpdateCount = 1; // use partial update
    }
+    Log_info("Image size = %d vs excepted ", data_size,48000);


The magic number 48000 is hardcoded without explanation. This appears to be the buffer size calculation (800 * 480 / 8 = 48000 bytes for 1-bit display), but should be calculated dynamically based on display dimensions or defined as a named constant with clear documentation.

Suggested change

memset(bbep.getBuffer(), 0xFF, 48000);

bbep.writePlane(PLANE_1);

Log_info("Image written to EPD buffer PLANE_1");

iRefreshMode = REFRESH_PARTIAL;

#endif

iUpdateCount = 1; // use partial update

}

Log_info("Image size = %d vs excepted ", data_size,48000);

const size_t displayBufferSize = (static_cast<size_t>(bbep.width()) * bbep.height()) / 8;

memset(bbep.getBuffer(), 0xFF, displayBufferSize);

bbep.writePlane(PLANE_1);

Log_info("Image written to EPD buffer PLANE_1");

iRefreshMode = REFRESH_PARTIAL;

#endif

iUpdateCount = 1; // use partial update

}

Log_info("Image size = %d vs excepted ", data_size, displayBufferSize);

Copilot · 2026-01-09T20:55:26Z

    {
+        bbep.fillScreen(BBEP_WHITE);


The fillScreen call with BBEP_WHITE is being added unconditionally before PNG drawing. This changes the behavior for all PNG images, not just those on the 3-color display. If this is needed specifically for the 3-color display to initialize the red plane, it should be conditional based on the panel type.

Suggested change

{

bbep.fillScreen(BBEP_WHITE);

{

#ifdef BB_EPAPER

bbep.fillScreen(BBEP_WHITE);

#endif

Copilot · 2026-01-09T20:55:27Z

+        // WICHTIG: Für Tri-Color SSD16xx auf FULL erzwingen (vermeidet Banding/Scanlines)
+        if (pBBEP->chip_type == BBEP_CHIP_SSD16xx && (pBBEP->iFlags & BBEP_3COLOR)) {
+            iMode = REFRESH_FULL; // statt REFRESH_FAST


Comments in the code are written in German (e.g., "WICHTIG: Für Tri-Color SSD16xx auf FULL erzwingen", "vermeidet Banding/Scanlines"). For maintainability and accessibility to the broader development community, code comments should be in English, consistent with the rest of the codebase.

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

bitbank2 · 2026-01-12T10:38:26Z

I have a Waveshare B/W/R panel on order and hopefully it will arrive later this week. I'll make the necessary changes for it to work in the core firmware.

bitbank2 · 2026-01-15T16:30:34Z

I received the B/W/R Waveshare 7.5" 800x480 V2 panel today. The changes you propose to bb_ep.inl in this PR don't work with this panel. However, the panel works correctly with the existing bb_epaper code. @SBajonczak where did you buy your B/W/R panel? What model number is printed on it?

SBajonczak · 2026-01-16T07:01:00Z

Ho i habe the v3 7.5 inch Paket from waveshare itseöf with their esp32 Module. So they normal inktial implementation did not work correctly.

But this happens only to the B/w/r display not to the b/w display. Because the Red laser was not filled empty in the Code only the b/w laser was filled. So this occurs i scanöines ghosting shadows and so on

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

bitbank2 · 2026-01-16T10:48:08Z

Sorry, I'm not sure what you mean. The B/W and B/W/R updates are exactly the same (at least in my code). The display only has 1 update mode built in. I will be adding a new configuration to trmnl-firmware for the Seeed Studio epaper PCB (ESP32-S3) connected to the B/W/R 7.5" panel. This requires a lot of new code in trmnl-firmware to match color images to B/W/R. Displaying 1-bit B/W content on the B/W/R panel is not much different from the current code.

SBajonczak added 4 commits January 4, 2026 09:32

Playing around with waveshare devcies

25a6e99

New Init sequence for R/B/W Waveshare 7.5 inch

e138db7

Added new enum WAVESHARE_3COLOR_800x480

2e43fb6

Using WAVESHARE_3COLOR_800x480 for th waveshare 3 color 7.5i display

c7c1064

Copilot AI review requested due to automatic review settings January 9, 2026 20:41

Copilot started reviewing on behalf of SBajonczak January 9, 2026 20:42 View session

ryanckulp requested review from bitbank2 and removed request for Copilot January 9, 2026 20:43

Revert to original

3ddf6b4

Copilot AI review requested due to automatic review settings January 9, 2026 20:49

Copilot started reviewing on behalf of SBajonczak January 9, 2026 20:50 View session

Copilot AI reviewed Jan 9, 2026

View reviewed changes

Update src/display.cpp

8f289e2

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Transformed to englisch comment

acce9b4

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

		if (!bWait) iRefreshMode = REFRESH_PARTIAL; // fast update when showing loading screen


		iRefreshMode =REFRESH_FULL;

	BBEPAPER bbep(WAVESHARE_3COLOR_800x480);
	BBEPAPER bbep(EP75_800x480);

-    BBEPAPER(int iPanel);
+    BBEPAPER(int iPanel);
+    // Utility method for advanced/external callers to prepare the image buffer
+    // for SSD1675B-based panels. This function is not invoked internally by
+    // the library but is exposed for applications that need fine-grained
+    // control over image preparation.

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bitbank2 commented Jan 12, 2026

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SBajonczak commented Jan 16, 2026

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