diff --git a/Marlin/src/HAL/HAL_LPC1768/u8g/u8g_com_HAL_LPC1768_st7920_sw_spi.cpp b/Marlin/src/HAL/HAL_LPC1768/u8g/u8g_com_HAL_LPC1768_st7920_sw_spi.cpp
index ec0ddc90fb..0931f7858a 100644
--- a/Marlin/src/HAL/HAL_LPC1768/u8g/u8g_com_HAL_LPC1768_st7920_sw_spi.cpp
+++ b/Marlin/src/HAL/HAL_LPC1768/u8g/u8g_com_HAL_LPC1768_st7920_sw_spi.cpp
@@ -68,23 +68,15 @@
static pin_t SCK_pin_ST7920_HAL, MOSI_pin_ST7920_HAL_HAL;
static uint8_t SPI_speed = 0;
-static uint8_t rs_last_state = 255;
static void u8g_com_LPC1768_st7920_write_byte_sw_spi(uint8_t rs, uint8_t val) {
-
- if (rs != rs_last_state) { // time to send a command/data byte
+ static uint8_t rs_last_state = 255;
+ if (rs != rs_last_state) {
+ // Transfer Data (FA) or Command (F8)
+ swSpiTransfer(rs ? 0x0FA : 0x0F8, SPI_speed, SCK_pin_ST7920_HAL, -1, MOSI_pin_ST7920_HAL_HAL);
rs_last_state = rs;
-
- if (rs == 0)
- /* command */
- swSpiTransfer(0x0F8, SPI_speed, SCK_pin_ST7920_HAL, -1, MOSI_pin_ST7920_HAL_HAL);
- else
- /* data */
- swSpiTransfer(0x0FA, SPI_speed, SCK_pin_ST7920_HAL, -1, MOSI_pin_ST7920_HAL_HAL);
-
- DELAY_US(40); // give the controller some time to process the data: 20 is bad, 30 is OK, 40 is safe
+ DELAY_US(40); // Give the controller time to process the data: 20 is bad, 30 is OK, 40 is safe
}
-
swSpiTransfer(val & 0x0F0, SPI_speed, SCK_pin_ST7920_HAL, -1, MOSI_pin_ST7920_HAL_HAL);
swSpiTransfer(val << 4, SPI_speed, SCK_pin_ST7920_HAL, -1, MOSI_pin_ST7920_HAL_HAL);
}
diff --git a/Marlin/src/lcd/dogm/ultralcd_st7920_u8glib_rrd_AVR.cpp b/Marlin/src/lcd/dogm/ultralcd_st7920_u8glib_rrd_AVR.cpp
index e736110188..c99a7085a1 100644
--- a/Marlin/src/lcd/dogm/ultralcd_st7920_u8glib_rrd_AVR.cpp
+++ b/Marlin/src/lcd/dogm/ultralcd_st7920_u8glib_rrd_AVR.cpp
@@ -71,23 +71,23 @@ uint8_t u8g_dev_rrd_st7920_128x64_fn(u8g_t *u8g, u8g_dev_t *dev, uint8_t msg, vo
OUT_WRITE(ST7920_CLK_PIN, HIGH);
ST7920_CS();
- u8g_Delay(120); //initial delay for boot up
+ u8g_Delay(120); // Initial delay for boot up
ST7920_SET_CMD();
- ST7920_WRITE_BYTE(0x20); //non-extended mode
- ST7920_WRITE_BYTE(0x08); //display off, cursor+blink off
- ST7920_WRITE_BYTE(0x01); //clear DDRAM ram
- u8g_Delay(15); //delay for DDRAM clear
- ST7920_WRITE_BYTE(0x24); //extended mode
- ST7920_WRITE_BYTE(0x26); //extended mode + GDRAM active
- for (y = 0; y < (LCD_PIXEL_HEIGHT) / 2; y++) { //clear GDRAM
- ST7920_WRITE_BYTE(0x80 | y); //set y
- ST7920_WRITE_BYTE(0x80); //set x = 0
+ ST7920_WRITE_BYTE(0x20); // Non-extended mode
+ ST7920_WRITE_BYTE(0x08); // Display off, cursor+blink off
+ ST7920_WRITE_BYTE(0x01); // Clear DDRAM ram
+ u8g_Delay(15); // Delay for DDRAM clear
+ ST7920_WRITE_BYTE(0x24); // Extended mode
+ ST7920_WRITE_BYTE(0x26); // Extended mode + GDRAM active
+ for (y = 0; y < (LCD_PIXEL_HEIGHT) / 2; y++) { // Clear GDRAM
+ ST7920_WRITE_BYTE(0x80 | y); // Set y
+ ST7920_WRITE_BYTE(0x80); // Set x = 0
ST7920_SET_DAT();
- for (i = 0; i < 2 * (LCD_PIXEL_WIDTH) / 8; i++) //2x width clears both segments
+ for (i = 0; i < 2 * (LCD_PIXEL_WIDTH) / 8; i++) // 2x width clears both segments
ST7920_WRITE_BYTE(0);
ST7920_SET_CMD();
}
- ST7920_WRITE_BYTE(0x0C); //display on, cursor+blink off
+ ST7920_WRITE_BYTE(0x0C); // Display on, cursor+blink off
ST7920_NCS();
}
break;
@@ -104,15 +104,15 @@ uint8_t u8g_dev_rrd_st7920_128x64_fn(u8g_t *u8g, u8g_dev_t *dev, uint8_t msg, vo
for (i = 0; i < PAGE_HEIGHT; i ++) {
ST7920_SET_CMD();
if (y < 32) {
- ST7920_WRITE_BYTE(0x80 | y); //y
- ST7920_WRITE_BYTE(0x80); //x=0
+ ST7920_WRITE_BYTE(0x80 | y); // y
+ ST7920_WRITE_BYTE(0x80); // x = 0
}
else {
- ST7920_WRITE_BYTE(0x80 | (y - 32)); //y
- ST7920_WRITE_BYTE(0x80 | 8); //x=64
+ ST7920_WRITE_BYTE(0x80 | (y - 32)); // y
+ ST7920_WRITE_BYTE(0x80 | 8); // x = 64
}
ST7920_SET_DAT();
- ST7920_WRITE_BYTES(ptr, (LCD_PIXEL_WIDTH) / 8); //ptr is incremented inside of macro
+ ST7920_WRITE_BYTES(ptr, (LCD_PIXEL_WIDTH) / 8); // ptr incremented inside of macro!
y++;
}
ST7920_NCS();