From 94664bafad83dc22d78f66ce7535b331bdc97042 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?King=20K=C3=A9vin?= <kingkevin@cuvoodoo.info>
Date: Sun, 24 Jan 2016 21:54:42 +0100
Subject: [PATCH] precalculate all spi data

---
 lib/vfd.c | 124 ++++++++++++++++--------------------------------------
 lib/vfd.h |   4 --
 main.c    |  19 +++++----
 3 files changed, 47 insertions(+), 100 deletions(-)

diff --git a/lib/vfd.c b/lib/vfd.c
index 8a7a8ec..32d73ab 100644
--- a/lib/vfd.c
+++ b/lib/vfd.c
@@ -305,12 +305,9 @@ 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 uint32_t vfd_data[VFD_DRIVERS] = {0};
-static uint16_t vfd_spi[VFD_DRIVERS*2] = {0};
-static volatile uint8_t vfd_spi_i = 0;
-
-char vfd_digits[VFD_DIGITS] = {0};
-char vfd_matrixs[VFD_MATRIX] = {0};
+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
+static volatile uint8_t vfd_mux = 0; // which part to output
 
 /* set digit <nb> to ASCII character <c>
  * use the MSB of <c> to enable the dot */
@@ -319,11 +316,8 @@ void vfd_digit(uint8_t nb, char c)
 	if (!(nb<VFD_DIGITS)) { // check the digit exists
 		return;
 	}
-	
-	// clear data
-	for (uint8_t i=0; i<LENGTH(vfd_data); i++) {
-		vfd_data[i] = 0;
-	}
+
+	uint32_t vfd_data[VFD_DRIVERS] = {0}; // the data to be shifted out for the driver
 	
 	vfd_data[1] = 1<<(4+(9-nb)); // select digit
 	/* encode segment
@@ -350,6 +344,12 @@ void vfd_digit(uint8_t nb, char c)
 			vfd_data[1] |= (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;
+	}
 }
 
 /* set dot matrix <nb> to ASCII character <c>
@@ -361,10 +361,7 @@ void vfd_matrix(uint8_t nb, char c)
 		return;
 	} 
 	
-	// clear data
-	for (uint8_t i=0; i<LENGTH(vfd_data); i++) {
-		vfd_data[i] = 0;
-	}
+	uint32_t vfd_data[VFD_DRIVERS] = {0}; // the data to be shifted out for the driver
 	
 	// select matrix
 	if (nb<4) {
@@ -392,46 +389,11 @@ void vfd_matrix(uint8_t nb, char c)
 			vfd_data[2] |= pict5x7[i][4]<<24;
 		}
 	}
-}
 
-/* shift out the VFD data */
-void vfd_shift(void)
-{
-	// prepare SPI data
-	for (uint8_t i=0; i<LENGTH(vfd_data) && (uint8_t)(i*2+1)<LENGTH(vfd_spi); i++) {
-		vfd_spi[i*2] = vfd_data[i];
-		vfd_spi[i*2+1] = vfd_data[i]>>16;
-	}
-	vfd_spi_i = 0;
-	
-	// enable SPI (the tx empty interrupt will trigger)
-	spi_enable(VFD_SPI);
-}
-
-/* transmit every digit and matrix */
-void vfd_transmit(void)
-{
-	for (uint8_t i=0; i<LENGTH(vfd_digits); i++) {
-		if (vfd_digits[i]==0) {
-			continue; // skip unused digits
-		}
-		vfd_digit(i,vfd_digits[i]); // set digit
-		vfd_shift(); // shift out data
-		// let the fluorescence glow up a bit
-		for (uint32_t j = 0; j < 0x2000; j++) {
-			__asm__("nop");
-		}
-	}
-	for (uint8_t i=0; i<LENGTH(vfd_matrixs); i++) {
-		if (vfd_matrixs[i]==0) {
-			continue; // skip unused matrix
-		}
-		vfd_matrix(i,vfd_matrixs[i]); // set matrix
-		vfd_shift(); // shift out data
-		// let the fluorescence glow up a bit
-		for (uint32_t j = 0; j < 0x2000; j++) {
-			__asm__("nop");
-		}
+	// 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;
 	}
 }
 
@@ -439,14 +401,10 @@ void vfd_transmit(void)
  * the data has to be transmitted separately */
 void vfd_clear(void)
 {
-	for (uint8_t i=0; i<LENGTH(vfd_digits); i++) {
-		vfd_digits[i] = 0;
-	}
-	for (uint8_t i=0; i<LENGTH(vfd_matrixs); i++) {
-		vfd_matrixs[i] = 0;
-	}
-	for (uint8_t i=0; i<LENGTH(vfd_data); i++) {
-		vfd_data[i] = 0;
+	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;
+		}
 	}
 }
 
@@ -454,14 +412,10 @@ void vfd_clear(void)
  * the data has to be transmitted separately */
 void vfd_test(void)
 {
-	for (uint8_t i=0; i<LENGTH(vfd_digits); i++) {
-		vfd_digits[i] = '8';
-	}
-	for (uint8_t i=0; i<LENGTH(vfd_matrixs); i++) {
-		vfd_matrixs[i] = 0x80+LENGTH(pict5x7)-1;
-	}
-	for (uint8_t i=0; i<LENGTH(vfd_data); i++) {
-		vfd_data[i] = ~0;
+	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;
+		}
 	}
 }
 
@@ -526,8 +480,8 @@ void vfd_setup(void)
 	spi_enable_software_slave_management(VFD_SPI); 
 	spi_set_nss_high(VFD_SPI); // set NSS high
 	
-	spi_enable_tx_buffer_empty_interrupt(VFD_SPI); // enable TX empty interrupt
     nvic_enable_irq(VFD_SPI_IRQ); // enable SPI interrupt
+	spi_enable(VFD_SPI); // enable SPI (the tx empty interrupt will trigger)
 	
 	/* setup timer to refresh display */
 	rcc_periph_clock_enable(VFD_TIMER_RCC); // enable clock for timer block
@@ -548,11 +502,14 @@ void spi2_isr(void)
 #endif
 {
 	if (SPI_SR(VFD_SPI) & SPI_SR_TXE) { // transmission buffer empty
-		if (vfd_spi_i<LENGTH(vfd_spi)) { // check if data is available
+		if (vfd_spi_i<LENGTH(vfd_spi[0])) { // check if data is available
 			gpio_clear(VFD_PORT, VFD_NLE); // slave select to latch data
-			spi_send(VFD_SPI, vfd_spi[vfd_spi_i++]); // send next data
+			spi_send(VFD_SPI, vfd_spi[vfd_mux][vfd_spi_i++]); // send next data
 		} else { // all data transmitted
-			spi_clean_disable(VFD_SPI); // wait for transmission to complete
+			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
+			spi_disable_tx_buffer_empty_interrupt(VFD_SPI); // no need to wait for new data
+			gpio_set(VFD_PORT, VFD_NLE); // output latched data
 		}
 	}
 }
@@ -567,21 +524,12 @@ void tim4_isr(void)
 void tim5_isr(void)
 #endif
 {
-	static uint8_t vfd_mux = 0; // which part to output
-
+	//gpio_toggle(LED_PORT, LED_PIN);
 	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
-		if (vfd_mux<LENGTH(vfd_digits)) {
-			if (vfd_digits[vfd_mux]!=0) { // skip unused digits
-				vfd_digit(vfd_mux,vfd_digits[vfd_mux]); // set digit
-				vfd_shift(); // shift out data
-			}
-		} else if (vfd_mux<LENGTH(vfd_digits)+LENGTH(vfd_matrixs)) {
-			if (vfd_matrixs[vfd_mux-LENGTH(vfd_digits)]!=0) { // skip unused matrix
-				vfd_matrix(vfd_mux-LENGTH(vfd_digits),vfd_matrixs[vfd_mux-LENGTH(vfd_digits)]); // set matrix
-				vfd_shift(); // shift out data
-			}
-		}
-		vfd_mux = (vfd_mux+1)%(LENGTH(vfd_digits)+LENGTH(vfd_matrixs)); // got to next segment
+    	vfd_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
 	}
 }
diff --git a/lib/vfd.h b/lib/vfd.h
index eb438cf..3036e64 100644
--- a/lib/vfd.h
+++ b/lib/vfd.h
@@ -31,8 +31,6 @@ void vfd_digit(uint8_t nb, char c);
 /* set dot matrix <nb> to ASCII character <c>
  * non ASCII characters are used for pictures */
 void vfd_matrix(uint8_t nb, char c);
-/* shift out the VFD data */
-void vfd_shift(void);
 /* clear VFD display
  * the data has to be transmitted separately */
 void vfd_clear(void);
@@ -40,8 +38,6 @@ void vfd_clear(void);
  * the data has to be transmitted separately */
 void vfd_test(void);
 /* transmit every digit and matrix */
-void vfd_transmit(void);
-/* switch VFD display on */
 void vfd_on(void);
 /* switch VFD display off */
 void vfd_off(void);
diff --git a/main.c b/main.c
index 329522b..2e6972b 100644
--- a/main.c
+++ b/main.c
@@ -82,23 +82,20 @@ int main(void)
 
 
 	vfd_on(); // switch on VFD
+	vfd_refresh_on();
 	vfd_test();
-	vfd_shift();
 	for (uint32_t i = 0; i < 0x800000; i++) {
 		__asm__("nop");
 	}
 	vfd_clear();
-	vfd_shift();
-	vfd_digit(0,'0');
-	vfd_shift();
-	
+
 	bool vfd_flag = false;
 	bool refresh = true;
 	for (uint8_t i=0; i<LENGTH(vfd_digits); i++) {
-		vfd_digits[i] = '0'+i;
+		vfd_digit(i,'0'+i);
 	}
 	for (uint8_t i=0; i<LENGTH(vfd_matrixs); i++) {
-		vfd_matrixs[i] = 'A'+i;
+		vfd_matrix(i,'A'+i);
 	}
 	while (true) {
 		while (usart_received) { // echo every received character
@@ -112,7 +109,13 @@ int main(void)
 		while (vfd_flag) {
 			vfd_flag = false;
 			gpio_toggle(LED_PORT, LED_PIN); // toggle LED
-			refresh ? vfd_refresh_on() : vfd_refresh_off();
+			if (refresh) {
+				printf("on\n");
+				vfd_refresh_on();
+			} else {
+				printf("off\n");
+				vfd_refresh_off();
+			}
 			refresh = !refresh;
 		}
 		__WFI(); // go to sleep