Added PCD8544 to readme, addressed PR comments

Author: mringwal

README.md

@@ -30,6 +30,7 @@ swap of RGB565 color on the LVGL configuration menuconfig (it's not handled auto
 | RA8875                                      | TFT        | SPI                    | 16: RGB565                   | Yes                                    |
 | SH1107                                      | Monochrome | SPI                    | 1: 1byte per pixel           | No                                     |
 | SSD1306                                     | Monochrome | I2C                    | 1: 1byte per pixel           | No                                     |
+| PCD8544                                     | Monochrome | SPI                    | 1: 1byte per pixel           | No                                     |
 | IL3820                                      | e-Paper    | SPI                    | 1: 1byte per pixel           | No                                     |
 | UC8151D/ GoodDisplay GDEW0154M10 DES        | e-Paper    | SPI                    | 1: 1byte per pixel           | No                                     |
 | FitiPower JD79653A/ GoodDisplay GDEW0154M09 | e-Paper    | SPI                    | 1: 1byte per pixel           | No                                     |

lvgl_tft/pcd8544.c

@@ -116,9 +116,12 @@ void pcd8544_flush(lv_disp_drv_t * disp_drv, const lv_area_t * area, lv_color_t
 
     uint8_t * buf = (uint8_t *) color_map;
 
+    // Check if the whole frame buffer can be sent in a single SPI transaction
+
     if ((area->x1 == 0) && (area->y1 == 0) && (area->x2 == (disp_drv->hor_res - 1)) && (area->y2 == (disp_drv->ver_res - 1))){
 
-        // optimize flush of complete frame buffer in a single SPI transaction
+        // send complete frame buffer at once. 
+        // NOTE: disp_spi_send_colors triggers lv_disp_flush_ready
 
         pcd8544_send_cmd(0x40);  /* set Y address */
         pcd8544_send_cmd(0x80);  /* set X address */
@@ -134,13 +137,12 @@ void pcd8544_flush(lv_disp_drv_t * disp_drv, const lv_area_t * area, lv_color_t
         uint16_t bank;
         uint16_t cols_to_update = area->x2 - area->x1 + 1;
         for (bank = bank_start ; bank <= bank_end ; bank++ ){
-            pcd8544_send_cmd(0x40 | bank ); /* set Y address */
+            pcd8544_send_cmd(0x40 | bank );      /* set Y address */
             pcd8544_send_cmd(0x80 | area->x1 );  /* set X address */
             uint16_t offset = bank * disp_drv->hor_res + area->x1;
             pcd8544_send_data(&buf[offset], cols_to_update);
         }
 
         lv_disp_flush_ready(disp_drv);
-
     }
 }

lvgl_tft/pcd8544.h

@@ -11,9 +11,9 @@
 extern "C" {
 #endif
 
-    /*********************
-     *      INCLUDES
-     *********************/
+/*********************
+ *      INCLUDES
+ *********************/
 #include <stdbool.h>
 
 #ifdef LV_LVGL_H_INCLUDE_SIMPLE
@@ -22,32 +22,32 @@ extern "C" {
 #include "lvgl/lvgl.h"
 #endif
 
-    /*********************
-     *      DEFINES
-     *********************/
+/*********************
+ *      DEFINES
+ *********************/
 
 #define PCD8544_DC   CONFIG_LV_DISP_PIN_DC
 #define PCD8544_RST  CONFIG_LV_DISP_PIN_RST
 #define PCD8544_BCKL CONFIG_LV_DISP_PIN_BCKL
 
-    /**********************
-     *      TYPEDEFS
-     **********************/
+/**********************
+ *      TYPEDEFS
+ **********************/
 
-    /**********************
-     * GLOBAL PROTOTYPES
-     **********************/
+/**********************
+ * GLOBAL PROTOTYPES
+ **********************/
 
-    void pcd8544_init(void);
-    void pcd8544_flush(lv_disp_drv_t * drv, const lv_area_t * area, lv_color_t * color_map);
-    void pcd8544_rounder(lv_disp_drv_t * disp_drv, lv_area_t *area);
-    void pcd8544_set_px_cb(lv_disp_drv_t * disp_drv, uint8_t * buf, lv_coord_t buf_w, lv_coord_t x, lv_coord_t y,
-                           lv_color_t color, lv_opa_t opa);
-    void pcd8544_set_contrast(uint8_t contrast);
+void pcd8544_init(void);
+void pcd8544_flush(lv_disp_drv_t * drv, const lv_area_t * area, lv_color_t * color_map);
+void pcd8544_rounder(lv_disp_drv_t * disp_drv, lv_area_t *area);
+void pcd8544_set_px_cb(lv_disp_drv_t * disp_drv, uint8_t * buf, lv_coord_t buf_w, lv_coord_t x, lv_coord_t y,
+                       lv_color_t color, lv_opa_t opa);
+void pcd8544_set_contrast(uint8_t contrast);
 
-    /**********************
-     *      MACROS
-     **********************/
+/**********************
+ *      MACROS
+ **********************/
 
 
 #ifdef __cplusplus