add support for 4.2 inch epaper display from WeAct Studio (partial up… (#21717)

* add support for 4.2 inch epaper display from WeAct Studio (partial update)

* make ep_mode=3 decision more clear, reinserted an mistakenly removed comment

---------

Co-authored-by: timehlers <>

lib/lib_display/UDisplay/uDisplay.cpp

@@ -707,6 +707,11 @@ void UfsCheckSDCardInit(void);
   }
 #endif
 
+  if ((epcoffs_full || epcoffs_part) && !(lutfsize || lutpsize)) {
+    // no lutfsize or lutpsize, but epcoffs_full or epcoffs_part
+    ep_mode = 3;
+  }
+
 #ifdef UDSP_DEBUG
   Serial.printf("Device : %s\n", dname);
   Serial.printf("xs : %d\n", gxs);
@@ -907,7 +912,7 @@ uint16_t index = 0;
     SPI_CS_LOW
     iob = dsp_cmds[cmd_offset++];
     index++;
-    if (ep_mode == 1 && iob >= EP_RESET) {
+    if ((ep_mode == 1 || ep_mode == 3) && iob >= EP_RESET) {
       // epaper pseudo opcodes
       uint8_t args = dsp_cmds[cmd_offset++];
       index++;
@@ -3429,6 +3434,9 @@ void uDisplay::Init_EPD(int8_t p) {
   if (ep_mode == 1) {
     ClearFrameMemory(0xFF);
     Updateframe_EPD();
+  } else if (ep_mode == 3) {
+    ClearFrameMemory(0xFF);
+    Updateframe_EPD();
   } else {
     ClearFrame_42();
   }
@@ -3518,7 +3526,7 @@ void uDisplay::SetLut(const unsigned char* lut) {
 }
 
 void uDisplay::Updateframe_EPD(void) {
-  if (ep_mode == 1) {
+  if (ep_mode == 1 || ep_mode == 3) {
     switch (ep_update_mode) {
       case DISPLAY_INIT_PARTIAL:
         if (epc_part_cnt) {
@@ -3547,15 +3555,33 @@ void uDisplay::DisplayFrame_29(void) {
 }
 
 void uDisplay::SetMemoryArea(int x_start, int y_start, int x_end, int y_end) {
-    spi_command_EPD(SET_RAM_X_ADDRESS_START_END_POSITION);
+    int x_start1 = (x_start >> 3) & 0xFF;
+    int x_end1 = (x_end >> 3) & 0xFF;
+    int y_start1 = y_start & 0xFF;
+    int y_start2 = (y_start >> 8) & 0xFF;
+    int y_end1 = y_end & 0xFF;
+    int y_end2 = (y_end >> 8) & 0xFF;
     /* x point must be the multiple of 8 or the last 3 bits will be ignored */
-    spi_data8_EPD((x_start >> 3) & 0xFF);
-    spi_data8_EPD((x_end >> 3) & 0xFF);
-    spi_command_EPD(SET_RAM_Y_ADDRESS_START_END_POSITION);
-    spi_data8_EPD(y_start & 0xFF);
-    spi_data8_EPD((y_start >> 8) & 0xFF);
-    spi_data8_EPD(y_end & 0xFF);
-    spi_data8_EPD((y_end >> 8) & 0xFF);
+
+    if (ep_mode == 3) {
+        spi_command_EPD(SET_RAM_X_ADDRESS_START_END_POSITION);
+        spi_data8_EPD(x_start1);
+        spi_data8_EPD(x_end1);
+        spi_command_EPD(SET_RAM_Y_ADDRESS_START_END_POSITION);
+        spi_data8_EPD(y_end1);
+        spi_data8_EPD(y_end2);
+        spi_data8_EPD(y_start1);
+        spi_data8_EPD(y_start2);
+    } else {
+        spi_command_EPD(SET_RAM_X_ADDRESS_START_END_POSITION);
+        spi_data8_EPD(x_start1);
+        spi_data8_EPD(x_end1);
+        spi_command_EPD(SET_RAM_Y_ADDRESS_START_END_POSITION);
+        spi_data8_EPD(y_start1);
+        spi_data8_EPD(y_start2);
+        spi_data8_EPD(y_end1);
+        spi_data8_EPD(y_end2);
+    }
 }
 
 void uDisplay::SetFrameMemory(const unsigned char* image_buffer) {
@@ -3569,12 +3595,27 @@ void uDisplay::SetFrameMemory(const unsigned char* image_buffer) {
 }
 
 void uDisplay::SetMemoryPointer(int x, int y) {
+    int x1;
+    int y1;
+    int y2;
+
+    if (ep_mode == 3) {
+        x1 = (x >> 3) & 0xFF;
+        y--;
+        y1 = y & 0xFF;
+        y2 = (y >> 8) & 0xFF;
+    } else {
+        x1 = (x >> 3) & 0xFF;
+        y1 = y & 0xFF;
+        y2 = (y >> 8) & 0xFF;
+    }
+
     spi_command_EPD(SET_RAM_X_ADDRESS_COUNTER);
     /* x point must be the multiple of 8 or the last 3 bits will be ignored */
-    spi_data8_EPD((x >> 3) & 0xFF);
+    spi_data8_EPD(x1);
     spi_command_EPD(SET_RAM_Y_ADDRESS_COUNTER);
-    spi_data8_EPD(y & 0xFF);
-    spi_data8_EPD((y >> 8) & 0xFF);
+    spi_data8_EPD(y1);
+    spi_data8_EPD(y2);
 }
 
 #if 0

tasmota/displaydesc/WeAct_epaper42_display.ini

@@ -0,0 +1,41 @@
+:H,E-PAPER-42-WeAct,400,300,1,SPI,4,*,*,*,*,*,*,*,10
+:S,1,1,1,0,10,10
+:I
+12,0
+63,1,80
+01,3,2b,01,01
+3c,1,01
+67,0;
+20,0
+63,1,80
+24,0
+66,0
+20,0
+63,1,80
+62,0
+:f
+64,0
+65,0
+24,0
+66,0
+21,2,40,00
+22,1,f7
+20,0
+63,1,80
+:p
+62,0
+22,1,c0
+20,0
+63,1,80
+64,0
+65,0
+24,0
+66,0
+21,2,00,00
+22,1,fc
+20,0
+63,1,80
+62,0
+
+:T,350,35,10
+#