From 78e2f7bb1cbc48d9fcfb340a3cd9641ac6020760 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?King=20K=C3=A9vin?= <kingkevin@cuvoodoo.info>
Date: Mon, 25 Jan 2016 00:39:29 +0100
Subject: [PATCH] combine the driver data for digits and matrix

---
 global.h  |  3 ++
 lib/vfd.c | 88 ++++++++++++++++++++++++++++---------------------------
 main.c    |  3 --
 3 files changed, 48 insertions(+), 46 deletions(-)

diff --git a/global.h b/global.h
index 297b35a..559ae06 100644
--- a/global.h
+++ b/global.h
@@ -14,6 +14,9 @@
  */
 /* Copyright (c) 2016 King Kévin <kingkevin@cuvoodoo.info> */
 
+/* get the length of an array */
+#define LENGTH(x) (sizeof(x) / sizeof((x)[0]))
+
 /* system clock frequency in Hz */
 #define SYSTEM_CLOCK_FREQ 72000000
 
diff --git a/lib/vfd.c b/lib/vfd.c
index 32d73ab..d44275d 100644
--- a/lib/vfd.c
+++ b/lib/vfd.c
@@ -30,9 +30,6 @@
 #include "global.h" // global definitions
 #include "vfd.h" // VFD library API
 
-/* get the length of an array */
-#define LENGTH(x) (sizeof(x) / sizeof((x)[0]))
-
 /* supertex HV518 VFD driver pins */
 /* port on which the pins to control the supertex HV518 VFD driver are
  * we use port A because of the SPI interface */
@@ -304,10 +301,14 @@ static const uint8_t pict5x7[][5] = {
 };
 
 /* the 32 bits values to be shifted out to the VFD driver
- * split into 16 bit for SPI transfer */
-static uint16_t vfd_spi[VFD_DIGITS+VFD_MATRIX][VFD_DRIVERS*2] = {0};
-static volatile uint8_t vfd_spi_i = 0; // which driver data is being transmitted
+ * split into 16 bit for SPI transfer
+ * since the bits for digits and matrix are independant, they can be conbined
+ * we have more matrix (12) than digits (10)
+ */
+static uint16_t driver_data[VFD_MATRIX][VFD_DRIVERS*2] = {0};
+static volatile uint8_t spi_i = 0; // which driver data is being transmitted
 static volatile uint8_t vfd_mux = 0; // which part to output
+static const uint32_t digit_mask = 0x00fff0; // the bits used for selecting then digit and 7 segment anodes (for the second driver)
 
 /* set digit <nb> to ASCII character <c>
  * use the MSB of <c> to enable the dot */
@@ -317,9 +318,9 @@ void vfd_digit(uint8_t nb, char c)
 		return;
 	}
 
-	uint32_t vfd_data[VFD_DRIVERS] = {0}; // the data to be shifted out for the driver
+	uint32_t digit_data = 0; // the data to be shifted out for the driver (for the second driver)
 	
-	vfd_data[1] = 1<<(4+(9-nb)); // select digit
+	digit_data = 1<<(4+(9-nb)); // select digit
 	/* encode segment
 	 * here the bit order (classic 7 segment + underline and dot)
 	 *   3_
@@ -328,28 +329,27 @@ void vfd_digit(uint8_t nb, char c)
 	 *   0_2,
 	 * */
 	if (false) { // add the underline (not encoded)
-		vfd_data[1] |= (1<<(14));
+		digit_data |= (1<<(14));
 	}
 	if (c&0x80) { // add the dot (encoded in the 8th bit)
-		vfd_data[1] |= (1<<(15));
+		digit_data |= (1<<(15));
 	}
 	if (false) { // add the comma (not encoded)
-		vfd_data[1] |= (1<<(16));
+		digit_data |= (1<<(16));
 	}
 	
 	c &= 0x7f; // only take the ASCII part
 	if (c>=' ') { // only take printable characters
 		uint8_t i = c-' '; // get index for character
 		if (i<LENGTH(ascii_7segments)) {
-			vfd_data[1] |= (ascii_7segments[i]<<(17)); // add encoded segments to memory
+			digit_data |= (ascii_7segments[i]<<(17)); // add encoded segments to memory
 		}
 	}
 
-	// prepare the data for SPI to shift it out
-	for (uint8_t i=0; i<LENGTH(vfd_data); i++) {
-		vfd_spi[nb][i*2] = vfd_data[i];
-		vfd_spi[nb][i*2+1] = vfd_data[i]>>16;
-	}
+	digit_data &= digit_mask; // be sure only the bits for the digit are used
+	digit_data |= (driver_data[nb][2]+(driver_data[nb][3]<<16))&~digit_mask; // get the existing data and add the bits for the digit
+	driver_data[nb][2] = digit_data; // write back data (least significant half)
+	driver_data[nb][3] = (digit_data>>16); // write back data (most significant half)
 }
 
 /* set dot matrix <nb> to ASCII character <c>
@@ -361,39 +361,41 @@ void vfd_matrix(uint8_t nb, char c)
 		return;
 	} 
 	
-	uint32_t vfd_data[VFD_DRIVERS] = {0}; // the data to be shifted out for the driver
+	uint32_t matrix_data[VFD_DRIVERS] = {0}; // the data to be shifted out for the driver
 	
 	// select matrix
 	if (nb<4) {
-		vfd_data[1] = 1<<(3-nb); 
+		matrix_data[1] = 1<<(3-nb); 
 	} else {
-		vfd_data[0] = 1<<(35-nb);
+		matrix_data[0] = 1<<(35-nb);
 	}
 	
 	if ((c<0x80) && (c>=' ')) { // only take printable characters
 		uint8_t i = c-' '; // get index for character
 		if (i<LENGTH(font5x7)) {
-			vfd_data[1] |= font5x7[i][0]<<24;
-			vfd_data[2] |= font5x7[i][1]<<0;
-			vfd_data[2] |= font5x7[i][2]<<8;
-			vfd_data[2] |= font5x7[i][3]<<16;
-			vfd_data[2] |= font5x7[i][4]<<24;
+			matrix_data[1] |= font5x7[i][0]<<24;
+			matrix_data[2] |= font5x7[i][1]<<0;
+			matrix_data[2] |= font5x7[i][2]<<8;
+			matrix_data[2] |= font5x7[i][3]<<16;
+			matrix_data[2] |= font5x7[i][4]<<24;
 		}
 	} else if (c>0x7f) { // the non ASCII character are used for pictures
 		uint8_t i = c-0x80; // get index for character
 		if (i<LENGTH(pict5x7)) {
-			vfd_data[1] |= pict5x7[i][0]<<24;
-			vfd_data[2] |= pict5x7[i][1]<<0;
-			vfd_data[2] |= pict5x7[i][2]<<8;
-			vfd_data[2] |= pict5x7[i][3]<<16;
-			vfd_data[2] |= pict5x7[i][4]<<24;
+			matrix_data[1] |= pict5x7[i][0]<<24;
+			matrix_data[2] |= pict5x7[i][1]<<0;
+			matrix_data[2] |= pict5x7[i][2]<<8;
+			matrix_data[2] |= pict5x7[i][3]<<16;
+			matrix_data[2] |= pict5x7[i][4]<<24;
 		}
 	}
 
+	matrix_data[1] &= ~digit_mask; // be sure only the bits for the matrix are used
+	matrix_data[1] |= (driver_data[nb][2]+(driver_data[nb][3]<<16))&digit_mask; // get the existing data for the digit
 	// prepare the data for SPI to shift it out
-	for (uint8_t i=0; i<LENGTH(vfd_data); i++) {
-		vfd_spi[nb+VFD_DIGITS][i*2] = vfd_data[i];
-		vfd_spi[nb+VFD_DIGITS][i*2+1] = vfd_data[i]>>16;
+	for (uint8_t i=0; i<LENGTH(matrix_data); i++) {
+		driver_data[nb][i*2] = matrix_data[i];
+		driver_data[nb][i*2+1] = matrix_data[i]>>16;
 	}
 }
 
@@ -401,9 +403,9 @@ void vfd_matrix(uint8_t nb, char c)
  * the data has to be transmitted separately */
 void vfd_clear(void)
 {
-	for (uint8_t i=0; i<LENGTH(vfd_spi); i++) {
-		for (uint8_t j=0; j<LENGTH(vfd_spi[0]); j++) {
-			vfd_spi[i][j] = 0;
+	for (uint8_t i=0; i<LENGTH(driver_data); i++) {
+		for (uint8_t j=0; j<LENGTH(driver_data[0]); j++) {
+			driver_data[i][j] = 0;
 		}
 	}
 }
@@ -412,9 +414,9 @@ void vfd_clear(void)
  * the data has to be transmitted separately */
 void vfd_test(void)
 {
-	for (uint8_t i=0; i<LENGTH(vfd_spi); i++) {
-		for (uint8_t j=0; j<LENGTH(vfd_spi[0]); j++) {
-			vfd_spi[i][j] = ~0;
+	for (uint8_t i=0; i<LENGTH(driver_data); i++) {
+		for (uint8_t j=0; j<LENGTH(driver_data[0]); j++) {
+			driver_data[i][j] = ~0;
 		}
 	}
 }
@@ -502,9 +504,9 @@ void spi2_isr(void)
 #endif
 {
 	if (SPI_SR(VFD_SPI) & SPI_SR_TXE) { // transmission buffer empty
-		if (vfd_spi_i<LENGTH(vfd_spi[0])) { // check if data is available
+		if (spi_i<LENGTH(driver_data[0])) { // check if data is available
 			gpio_clear(VFD_PORT, VFD_NLE); // slave select to latch data
-			spi_send(VFD_SPI, vfd_spi[vfd_mux][vfd_spi_i++]); // send next data
+			spi_send(VFD_SPI, driver_data[vfd_mux][spi_i++]); // send next data
 		} else { // all data transmitted
 			spi_disable_tx_buffer_empty_interrupt(VFD_SPI); // no need to wait for new data
 			while (SPI_SR(VFD_SPI) & SPI_SR_BSY); // wait for data to be shifted out
@@ -528,8 +530,8 @@ void tim5_isr(void)
 	if (timer_get_flag(VFD_TIMER, TIM_SR_UIF)) { // overflow even happened
 		gpio_toggle(LED_PORT, LED_PIN);
 		timer_clear_flag(VFD_TIMER, TIM_SR_UIF); // clear flag
-    	vfd_spi_i = 0; // set the register to shift out
+    	spi_i = 0; // set the register to shift out
 		spi_enable_tx_buffer_empty_interrupt(VFD_SPI); // enable TX empty interrupt
-		vfd_mux = (vfd_mux+1)%LENGTH(vfd_spi); // got to next segment
+		vfd_mux = (vfd_mux+1)%LENGTH(driver_data); // got to next segment
 	}
 }
diff --git a/main.c b/main.c
index 2e6972b..7f6c791 100644
--- a/main.c
+++ b/main.c
@@ -36,9 +36,6 @@
 #include "usb_cdcacm.h" // USB CDC ACM utilities
 #include "vfd.h" // VFD driver
 
-/* get the length of an array */
-#define LENGTH(x) (sizeof(x) / sizeof((x)[0]))
-
 /* default output (i.e. for printf) */
 int _write(int file, char *ptr, int len)
 {