Merge pull request #44 from sifive/led_fade_demo

Add the led_fade demo which ships on HiFive1 boards

1 files changed, 160 insertions, 0 deletions

diff --git a/software/led_fade/led_fade.c b/software/led_fade/led_fade.c
new file mode 100644
index 0000000..775647a
--- /dev/null
+++ b/software/led_fade/led_fade.c
@@ -0,0 +1,160 @@
+// See LICENSE for license details.
+
+// This is the program which ships on the HiFive1
+// board, executing out of SPI Flash at 0x20400000.
+
+#include <stdint.h>
+#include "platform.h"
+
+static const char led_msg[] = "\a\n\r\n\r\
+55555555555555555555555555555555555555555555555\n\r\
+5555555 Are the LEDs Changing? [y/n]  555555555\n\r\
+55555555555555555555555555555555555555555555555\n\r";
+
+static const char sifive_msg[] = "\n\r\
+\n\r\
+                SIFIVE, INC.\n\r\
+\n\r\
+         5555555555555555555555555\n\r\
+        5555                   5555\n\r\
+       5555                     5555\n\r\
+      5555                       5555\n\r\
+     5555       5555555555555555555555\n\r\
+    5555       555555555555555555555555\n\r\
+   5555                             5555\n\r\
+  5555                               5555\n\r\
+ 5555                                 5555\n\r\
+5555555555555555555555555555          55555\n\r\
+ 55555           555555555           55555\n\r\
+   55555           55555           55555\n\r\
+     55555           5           55555\n\r\
+       55555                   55555\n\r\
+         55555               55555\n\r\
+           55555           55555\n\r\
+             55555       55555\n\r\
+               55555   55555\n\r\
+                 555555555\n\r\
+                   55555\n\r\
+                     5\n\r\
+\n\r\
+               'led_fade' Demo \n\r\
+\n\r";
+
+static void _putc(char c) {
+  while ((int32_t) UART0_REG(UART_REG_TXFIFO) < 0);
+  UART0_REG(UART_REG_TXFIFO) = c;
+}
+
+int _getc(char * c){
+  int32_t val = (int32_t) UART0_REG(UART_REG_RXFIFO);
+  if (val > 0) {
+    *c =  val & 0xFF;
+    return 1;
+  }
+  return 0;
+}
+
+
+static void _puts(const char * s) {
+  while (*s != '\0'){
+    _putc(*s++);
+  }
+}
+
+
+int main (void){
+
+  // Run off 16 MHz Crystal for accuracy.
+  PRCI_REG(PRCI_PLLCFG) = (PLL_REFSEL(1) | PLL_BYPASS(1));
+  PRCI_REG(PRCI_PLLCFG) |= (PLL_SEL(1));
+  // Turn off HFROSC to save power
+  PRCI_REG(PRCI_HFROSCCFG) = 0;
+  
+  // Configure UART to print
+  GPIO_REG(GPIO_OUTPUT_VAL) |= IOF0_UART0_MASK;
+  GPIO_REG(GPIO_OUTPUT_EN)  |= IOF0_UART0_MASK;
+  GPIO_REG(GPIO_IOF_SEL)    &= ~IOF0_UART0_MASK;
+  GPIO_REG(GPIO_IOF_EN)     |= IOF0_UART0_MASK;
+
+  // 115200 Baud Rate
+  UART0_REG(UART_REG_DIV) = 138;
+  UART0_REG(UART_REG_TXCTRL) = UART_TXEN;
+  UART0_REG(UART_REG_RXCTRL) = UART_RXEN;
+
+  // Wait a bit to avoid corruption on the UART.
+  // (In some cases, switching to the IOF can lead
+  // to output glitches, so need to let the UART
+  // reciever time out and resynchronize to the real 
+  // start of the stream.
+  volatile int i=0;
+  while(i < 10000){i++;}
+
+  _puts(sifive_msg);
+  //_puts("Config String:\n\r");
+  //_puts(*((const char **) 0x100C));
+  //_puts("\n\r");
+  _puts(led_msg);
+  
+  uint16_t r=0xFF;
+  uint16_t g=0;
+  uint16_t b=0;
+  char c = 0;
+  
+  // Set up RGB PWM
+  
+  PWM1_REG(PWM_CFG)   = 0;
+  // To balance the power consumption, make one left, one right, and one center aligned.
+  PWM1_REG(PWM_CFG)   = (PWM_CFG_ENALWAYS) | (PWM_CFG_CMP2CENTER);
+  PWM1_REG(PWM_COUNT) = 0;
+  
+  // Period is approximately 244 Hz
+  // the LEDs are intentionally left somewhat dim, 
+  // as the full brightness can be painful to look at.
+  PWM1_REG(PWM_CMP0)  = 0;
+
+  GPIO_REG(GPIO_IOF_SEL)    |= ( (1 << GREEN_LED_OFFSET) | (1 << BLUE_LED_OFFSET) | (1 << RED_LED_OFFSET));
+  GPIO_REG(GPIO_IOF_EN )    |= ( (1 << GREEN_LED_OFFSET) | (1 << BLUE_LED_OFFSET) | (1 << RED_LED_OFFSET));
+  GPIO_REG(GPIO_OUTPUT_XOR) &= ~( (1 << GREEN_LED_OFFSET) | (1 << BLUE_LED_OFFSET));
+  GPIO_REG(GPIO_OUTPUT_XOR) |= (1 << RED_LED_OFFSET);
+
+  while(1){
+    volatile uint64_t *  now = (volatile uint64_t*)(CLINT_BASE_ADDR + CLINT_MTIME);
+    volatile uint64_t then = *now + 100;
+    while (*now < then) { }
+  
+    if(r > 0 && b == 0){
+      r--;
+      g++;
+    }
+    if(g > 0 && r == 0){
+      g--;
+      b++;
+    }
+    if(b > 0 && g == 0){
+      r++;
+      b--;
+    }
+    
+    uint32_t G = g;
+    uint32_t R = r;
+    uint32_t B = b;
+    
+    PWM1_REG(PWM_CMP1)  = G << 4;            // PWM is low on the left, GPIO is low on the left side, LED is ON on the left.
+    PWM1_REG(PWM_CMP2)  = (B << 1) << 4;     // PWM is high on the middle, GPIO is low in the middle, LED is ON in the middle.
+    PWM1_REG(PWM_CMP3)  = 0xFFFF - (R << 4); // PWM is low on the left, GPIO is low on the right, LED is on on the right.
+  
+    // Check for user input
+    if (c == 0){
+      if (_getc(&c) != 0){
+        _putc(c);
+        _puts("\n\r");
+        
+        if ((c == 'y') || (c == 'Y')){
+          _puts("PASS\n\r");
+        } else{
+          _puts("FAIL\n\r");
+        }
+      }
+    }
+  }
+}