7 files changed, 147 insertions, 0 deletions
diff --git a/software/first/delay.S b/software/first/delay.S
new file mode 100644
index 0000000..cb49ba1
--- /dev/null
+++ b/software/first/delay.S
@@ -0,0 +1,26 @@
+.section .text
+.align 2
+.global delay
+.include "memory_map.inc"
+
+
+# a0 is delay in milliseconds argument
+
+delay:
+	addi sp, sp, -16 # Allocate stack frame
+	sw ra, 12(sp)    # save return address to the stack
+
+	li t0, MTIME     # load the timer register
+	lw t1, 0(t0)     # load value of the timer
+
+	li t2, MTIME_FREQUENCY # get clock freq (approx.)
+	mul t2, t2, a0         # multiply milliseconds with freq
+  add t2, t1, t2         # target mtime is now in t2
+
+1:
+  lw t1, 0(t0)      # load value of the timer
+	blt t1, t2, 1b    # keep looping until target mtime has been reached
+
+  lw ra, 12(sp)   # load return address
+  addi sp, sp, 16 # deallocate stack frame
+	ret
diff --git a/software/first/first.c b/software/first/first.c
new file mode 100644
index 0000000..ed6e91b
--- /dev/null
+++ b/software/first/first.c
@@ -0,0 +1,33 @@
+/* Copyright 2019 SiFive, Inc */
+/* SPDX-License-Identifier: Apache-2.0 */
+
+#include <stdio.h>
+#include "super_blink.h"
+
+int main() {
+    printf("Hello, cute waffle!\n");
+
+		int error = 0;
+		int ledNum = 0;
+		int colours[NUM_LEDS] = {
+			GREEN_LED,
+			RED_LED,
+			BLUE_LED,
+		};
+
+		setup_GPIO();
+
+		while (!error) {
+			set_LED(colours[ledNum], ON);
+			delay(DELAY);
+
+			error = set_LED(colours[ledNum], OFF);
+			delay(DELAY);
+
+			ledNum++;
+
+			if (ledNum >= NUM_LEDS) {
+				ledNum = 0;
+			}
+		}
+}
diff --git a/software/first/gpio.inc b/software/first/gpio.inc
new file mode 100644
index 0000000..37caeba
--- /dev/null
+++ b/software/first/gpio.inc
@@ -0,0 +1,8 @@
+.equ GPIO_OUTPUT_EN,  0x08
+.equ GPIO_OUTPUT_VAL, 0x0C
+.equ GPIO_OUTPUT_XOR, 0x40
+
+.equ  GPIO_RGB_PINS,  0x680000
+.equ  GPIO_RED_LED,   0x400000
+.equ  GPIO_BLUE_LED,   0x200000
+.equ  GPIO_GREEN_LED,  0x080000
diff --git a/software/first/memory_map.inc b/software/first/memory_map.inc
new file mode 100644
index 0000000..e28af43
--- /dev/null
+++ b/software/first/memory_map.inc
@@ -0,0 +1,3 @@
+.equ GPIO_CTRL_ADDR,  0x10012000
+.equ MTIME,           0x0200BFF8
+.equ MTIME_FREQUENCY, 33
diff --git a/software/first/set_LED.S b/software/first/set_LED.S
new file mode 100644
index 0000000..e436615
--- /dev/null
+++ b/software/first/set_LED.S
@@ -0,0 +1,46 @@
+.section .text
+.align 2
+.global set_LED
+.include "memory_map.inc"
+.include "gpio.inc"
+
+.equ  NOERROR,  0x0
+.equ  ERROR,    0x1
+.equ  LEDON,    0x1
+
+# a0 contains LED to set, desired LED state in a1
+# a0 is also the return value...
+
+set_LED:
+	addi sp, sp, -16 # Allocate stack frame
+	sw ra, 12(sp)    # save return address to the stack
+
+	li t0, GPIO_CTRL_ADDR      # load base GPIO address 
+	lw t1, GPIO_OUTPUT_VAL(t0) # load state
+
+	beqz a1, ledOff   # branch if == 0
+	li t2, LEDON      # load up on val into t2
+
+	beq a1, t2, ledOn # branch if on requested
+	li  a0, ERROR     # bad status request, return error
+  j exit
+
+
+ledOn:
+  or t1, t1, a0               # only change the value of the requested LED (xor in the video)
+  sw t1, GPIO_OUTPUT_VAL(t0)  # write new LED values to the right address
+	li a0, NOERROR              # success
+  j exit
+
+
+ledOff:
+  xor a0, a0, 0xffffffff       # invert bits so off bits are off
+  and t1, t1, a0               # turn of LEDs
+  sw t1, GPIO_OUTPUT_VAL(t0)   # write new LED values to the right address
+	li  a0, NOERROR              # success
+
+
+exit:
+  lw ra, 12(sp)   # load return address
+  addi sp, sp, 16 # deallocate stack frame
+	ret
diff --git a/software/first/setup_gpio.S b/software/first/setup_gpio.S
new file mode 100644
index 0000000..39003b4
--- /dev/null
+++ b/software/first/setup_gpio.S
@@ -0,0 +1,19 @@
+.section .text
+.align 2
+.global setup_GPIO
+.include "memory_map.inc"
+.include "gpio.inc"
+
+setup_GPIO:
+	addi sp, sp, -16 # Allocate stack frame
+	sw ra, 12(sp)    # save return address to the stack
+
+	li t0, GPIO_CTRL_ADDR      # load base GPIO address 
+	li t1, GPIO_RGB_PINS       # get RGB offsets
+	sw t1, GPIO_OUTPUT_EN(t0)  # enable output on the RGB pins
+	sw t1, GPIO_OUTPUT_XOR(t0) # set the RGB pins to active high
+	sw x0, GPIO_OUTPUT_VAL(t0) # set all pins to 0
+
+  lw ra, 12(sp)   # load return address
+  addi sp, sp, 16 # deallocate stack frame
+	ret
diff --git a/software/first/super_blink.h b/software/first/super_blink.h
new file mode 100644
index 0000000..74cc00a
--- /dev/null
+++ b/software/first/super_blink.h
@@ -0,0 +1,12 @@
+#define  DELAY     200
+#define  ON        0x01
+#define  OFF       0x00
+#define  NUM_LEDS  0x03
+
+#define  RED_LED    0x400000
+#define  BLUE_LED   0x200000
+#define  GREEN_LED  0x080000
+
+void setup_GPIO();
+int set_LED(int color, int state);
+void delay(int milliseconds);