Added offset method, offsets for 240x240, new firware.bin

README.md

@@ -9,8 +9,18 @@ display rotation, scrolling and drawing text using 8 and 16 bit wide bitmap
 fonts. Included are 12 bitmap fonts derived from classic pc text mode fonts
 and a couple of example programs that run on the TTGO T-Display.
 
+A firmware.bin file containing MicroPython v1.12-464-gcae77daf0 compiled
+using ESP IDF v3 with the st7789 C driver and the frozen python font files is
+available in the firmware directory.
+
 This is a work in progress.
 
+Thanks go out to:
+
+- https://github.com/devbis for the original driver this is based on.
+- https://github.com/hklang10 for letting me know of the new mp_raise_ValueError().
+- https://github.com/aleggon for finding the correct offsets for a 240x240 display.
+
 -- Russ
 
 Overview
@@ -184,7 +194,33 @@ This driver supports only 16bit colors in RGB565 notation.
   (0 degrees), 1-Landscape (90 degrees), 2-Inverse Portrait (180 degrees),
   3-Inverse Landscape (270 degrees)
 
-Also, the module exposes predefined colors:
+- `ST7789.offset(x_start, y_start)` The memory in the ST7789 controller is
+  configured for a 240x320 display. When using a smaller display like a
+  240x240 or 135x240 an offset needs to added to the x and y parameters so
+  that the pixels are written to the memory area that corresponds to the
+  visible display.  The offsets may need to be adjusted when rotating the
+  display.
+
+  For example the TTGO-TDisplay is 135x240 and uses the following offsets.
+  | Rotation | x_start | y_start |
+  |----------|---------|---------|
+  | 0        | 52      | 40      |
+  | 1        | 40      | 53      |
+  | 2        | 53      | 40      |
+  | 3        | 40      | 52      |
+
+  When the rotation method is called the driver will adjust the offsets for a
+  135x240 or 240x240 display. Your display may require using different offset
+  values, if so, use the `offset` method after `rotation` to set the offset
+  values.
+
+  The values needed for particular display may not be documented and may
+  require some experimentation to determine the correct values. One technique
+  is to draw a box the same size as the display and then make small changes
+  to the offsets until the display looks correct.
+
+
+The module exposes predefined colors:
   `BLACK`, `BLUE`, `RED`, `GREEN`, `CYAN`, `MAGENTA`, `YELLOW`, and `WHITE`
 
 

firmware/README.md

@@ -18,3 +18,13 @@ with the st7789 C driver and the frozen python font files:
 
 - vga1_bold_16x32.py
 - vga2_bold_16x32.py
+
+When using this firmware you can use the VGA fonts directly from flash to
+save RAM. For example, in the ttgo_hello.py program change the font import
+line from:
+
+`from fonts import vga2_bold_16x32 as font`
+
+to:
+
+`import vga2_bold_16x32 as font`

st7789/st7789.c

@@ -468,6 +468,11 @@ STATIC void set_rotation(st7789_ST7789_obj_t *self) {
                 self->xstart = 52;
                 self->ystart = 40;
         }
+        else if (self->display_width == 240) {
+                self->xstart = 0;
+                self->ystart = 0;
+
+        }
     }
     else if (self->rotation == 1) {         // Landscape
         madctl_value |= ST7789_MADCTL_MX | ST7789_MADCTL_MV;
@@ -477,6 +482,11 @@ STATIC void set_rotation(st7789_ST7789_obj_t *self) {
             self->xstart = 40;
             self->ystart = 53;
         }
+        else if (self->display_width == 240) {
+            self->xstart = 0;
+            self->ystart = 0;
+        }
+
     }
     else if (self->rotation == 2) {        // Inverted Portrait
         madctl_value |= ST7789_MADCTL_MX | ST7789_MADCTL_MY;
@@ -486,6 +496,11 @@ STATIC void set_rotation(st7789_ST7789_obj_t *self) {
             self->xstart = 53;
             self->ystart = 40;
         }
+        else if (self->display_width == 240) {
+            self->xstart = 0;
+            self->ystart = 80;
+        }
+
     }
     else if (self->rotation == 3) {         // Inverted Landscape
         madctl_value |= ST7789_MADCTL_MV | ST7789_MADCTL_MY;
@@ -495,6 +510,10 @@ STATIC void set_rotation(st7789_ST7789_obj_t *self) {
             self->xstart = 40;
             self->ystart = 52;
         }
+        else if (self->display_width == 240) {
+            self->xstart = 80;
+            self->ystart = 0;
+        }
     }
     const uint8_t madctl[] = { madctl_value };
     write_cmd(self, ST7789_MADCTL, madctl, 1);
@@ -638,6 +657,18 @@ STATIC mp_obj_t st7789_ST7789_rect(size_t n_args, const mp_obj_t *args) {
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(st7789_ST7789_rect_obj, 6, 6, st7789_ST7789_rect);
 
+STATIC mp_obj_t st7789_ST7789_offset(size_t n_args, const mp_obj_t *args) {
+    st7789_ST7789_obj_t *self = MP_OBJ_TO_PTR(args[0]);
+    mp_int_t xstart = mp_obj_get_int(args[1]);
+    mp_int_t ystart = mp_obj_get_int(args[2]);
+
+    self->xstart = xstart;
+    self->ystart = ystart;
+
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(st7789_ST7789_offset_obj, 3, 3, st7789_ST7789_offset);
+
 
 STATIC const mp_rom_map_elem_t st7789_ST7789_locals_dict_table[] = {
     // Do not expose internal functions to fit iram_0 section
@@ -664,6 +695,7 @@ STATIC const mp_rom_map_elem_t st7789_ST7789_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_height), MP_ROM_PTR(&st7789_ST7789_height_obj) },
     { MP_ROM_QSTR(MP_QSTR_vscrdef), MP_ROM_PTR(&st7789_ST7789_vscrdef_obj) },
     { MP_ROM_QSTR(MP_QSTR_vscsad), MP_ROM_PTR(&st7789_ST7789_vscsad_obj) },
+    { MP_ROM_QSTR(MP_QSTR_offset), MP_ROM_PTR(&st7789_ST7789_offset_obj) },
 
 };