Fix SSD1306 driver and board files to allow for seamless transfer of the command byte with the page line data without copying the data on to the stack.

4 files changed, 32 insertions, 18 deletions

diff --git a/drivers/gdisp/SSD1306/board_SSD1306_i2c.h b/drivers/gdisp/SSD1306/board_SSD1306_i2c.h
index 69c054f5..449d47ba 100644
--- a/drivers/gdisp/SSD1306/board_SSD1306_i2c.h
+++ b/drivers/gdisp/SSD1306/board_SSD1306_i2c.h
@@ -13,7 +13,8 @@
 #ifndef _GDISP_LLD_BOARD_H
 #define _GDISP_LLD_BOARD_H
 
-#define GDISP_BUS_MAX_TRANSFER_SIZE		64
+// The command byte to put on the front of each page line
+#define SSD1306_PAGE_PREFIX		0x40			 		// Co = 0, D/C = 1
 
 // For a multiple display configuration we would put all this in a structure and then
 //	set g->board to that structure.
@@ -116,14 +117,10 @@ static inline void write_cmd(GDisplay *g, uint8_t cmd) {
 }
 
 static inline void write_data(GDisplay *g, uint8_t* data, uint16_t length) {
-	uint8_t command[1];
 	(void) g;
 
-	command[0] = 0x40; 		// Co = 0, D/C = 1
-
 	i2cStart(&I2CD1, &i2cconfig);
-	i2cMasterTransmitTimeout(&I2CD1, SSD1306_I2C_ADDRESS, command, 1, NULL, 0, MS2ST(10));
-	i2cMasterTransmitTimeout(&I2CD1, SSD1306_I2C_ADDRESS, command, data, NULL, length, MS2ST(10));
+	i2cMasterTransmitTimeout(&I2CD1, SSD1306_I2C_ADDRESS, data, length, NULL, 0, MS2ST(10));
 	i2cStop(&I2CD1);
 }
 
diff --git a/drivers/gdisp/SSD1306/board_SSD1306_spi.h b/drivers/gdisp/SSD1306/board_SSD1306_spi.h
index 476c51bf..5b481630 100644
--- a/drivers/gdisp/SSD1306/board_SSD1306_spi.h
+++ b/drivers/gdisp/SSD1306/board_SSD1306_spi.h
@@ -13,7 +13,8 @@
 #ifndef _GDISP_LLD_BOARD_H
 #define _GDISP_LLD_BOARD_H
 
-#define GDISP_BUS_MAX_TRANSFER_SIZE		64
+// The command byte to put on the front of each page line
+#define SSD1306_PAGE_PREFIX		0x40			 		// Co = 0, D/C = 1
 
 // For a multiple display configuration we would put all this in a structure and then
 //	set g->board to that structure.
@@ -49,10 +50,12 @@ static const SPIConfig spi1config = {
 #endif
 
 static inline void init_board(GDisplay *g) {
+	unsigned	i;
 
 	// As we are not using multiple displays we set g->board to NULL as we don't use it.
 	g->board = 0;
 
+
 	switch(g->controllerdisplay) {
 	case 0:											// Set up for Display 0
 		// RESET pin.
@@ -115,14 +118,10 @@ static inline void write_cmd(GDisplay *g, uint8_t cmd) {
 }
 
 static inline void write_data(GDisplay *g, uint8_t* data, uint16_t length) {
-	uint8_t command[1];
 	(void) g;
 
-	command[0] = 0x40; 		// Co = 0, D/C = 1
-
 	spiStart(&SPID1, &spi1config);
 	spiSelect(&SPID1);
-	spiStartSend(&SPID1, 1, command);
 	spiStartSend(&SPID1, length, data);
 	spiUnselect(&SPID1);
 	spiStop(&SPID1);
diff --git a/drivers/gdisp/SSD1306/board_SSD1306_template.h b/drivers/gdisp/SSD1306/board_SSD1306_template.h
index ec7f44f5..5b4bd05c 100644
--- a/drivers/gdisp/SSD1306/board_SSD1306_template.h
+++ b/drivers/gdisp/SSD1306/board_SSD1306_template.h
@@ -17,12 +17,12 @@
 #define _GDISP_LLD_BOARD_H
 
 /**
- * @brief   How many bytes to write in one operation when updating the display.
- * @note	The screen size (in bytes) must evenly divide by this number.
+ * @brief   Optional: A byte to prefix on each display page line.
+ * @note	If not defined then no byte is prefixed on each page line.
  *
  * @notapi
  */
-#define GDISP_BUS_MAX_TRANSFER_SIZE		64
+//#define SSD1306_PAGE_PREFIX		0x40
 
 /**
  * @brief   Initialise the board for the display.
diff --git a/drivers/gdisp/SSD1306/gdisp_lld.c b/drivers/gdisp/SSD1306/gdisp_lld.c
index 81b3b692..390a9282 100644
--- a/drivers/gdisp/SSD1306/gdisp_lld.c
+++ b/drivers/gdisp/SSD1306/gdisp_lld.c
@@ -36,6 +36,13 @@
 #ifndef GDISP_INITIAL_BACKLIGHT

 	#define GDISP_INITIAL_BACKLIGHT	100

 #endif

+#ifdef SSD1306_PAGE_PREFIX

+	#define SSD1306_PAGE_WIDTH		(GDISP_SCREEN_WIDTH+1)

+	#define SSD1306_PAGE_OFFSET		1

+#else

+	#define SSD1306_PAGE_WIDTH		GDISP_SCREEN_WIDTH

+	#define SSD1306_PAGE_OFFSET		0

+#endif

 

 #define GDISP_FLG_NEEDFLUSH			(GDISP_FLG_DRIVER<<0)

 

@@ -54,7 +61,7 @@
 #define delay(us)			gfxSleepMicroseconds(us)

 #define delayms(ms)			gfxSleepMilliseconds(ms)

 

-#define xyaddr(x, y)		((x) + ((y)>>3)*GDISP_SCREEN_WIDTH)

+#define xyaddr(x, y)		(SSD1306_PAGE_OFFSET + (x) + ((y)>>3)*SSD1306_PAGE_WIDTH)

 #define xybit(y)			(1<<((y)&7))

 

 /*===========================================================================*/

@@ -70,7 +77,18 @@
 

 LLDSPEC bool_t gdisp_lld_init(GDisplay *g) {

 	// The private area is the display surface.

-	g->priv = gfxAlloc(GDISP_SCREEN_HEIGHT * GDISP_SCREEN_WIDTH / 8);

+	g->priv = gfxAlloc(GDISP_SCREEN_HEIGHT/8 * SSD1306_PAGE_WIDTH);

+

+	// Fill in the prefix command byte on each page line of the display buffer

+	// We can do it during initialisation as this byte is never overwritten.

+	#ifdef SSD1306_PAGE_PREFIX

+		{

+			unsigned	i;

+

+			for(i=0; i < GDISP_SCREEN_HEIGHT/8 * SSD1306_PAGE_WIDTH; i+=SSD1306_PAGE_WIDTH)

+				RAM(g)[i] = SSD1306_PAGE_PREFIX;

+		}

+	#endif

 

 	// Initialise the board interface

 	init_board(g);

@@ -131,8 +149,8 @@ LLDSPEC bool_t gdisp_lld_init(GDisplay *g) {
 

 		write_cmd(g, SSD1306_SETSTARTLINE | 0);

 

-		for(i=0; i < GDISP_SCREEN_WIDTH * GDISP_SCREEN_HEIGHT/8; i+=GDISP_BUS_MAX_TRANSFER_SIZE)

-			write_data(g, RAM(g)+i, GDISP_BUS_MAX_TRANSFER_SIZE);

+		for(i=0; i < GDISP_SCREEN_HEIGHT/8 * SSD1306_PAGE_WIDTH; i+=SSD1306_PAGE_WIDTH)

+			write_data(g, RAM(g)+i, SSD1306_PAGE_WIDTH);

 	}

 #endif