summaryrefslogtreecommitdiff
path: root/bootrom/demo
diff options
context:
space:
mode:
Diffstat (limited to 'bootrom/demo')
-rw-r--r--bootrom/demo/Makefile5
-rw-r--r--bootrom/demo/demo.S71
-rw-r--r--bootrom/demo/hello_msg.txt37
3 files changed, 113 insertions, 0 deletions
diff --git a/bootrom/demo/Makefile b/bootrom/demo/Makefile
new file mode 100644
index 0000000..dfe3663
--- /dev/null
+++ b/bootrom/demo/Makefile
@@ -0,0 +1,5 @@
+PROG := demo
+SRCS := demo.S
+EXTRAS := hello_msg.txt
+
+include ../bram.mk
diff --git a/bootrom/demo/demo.S b/bootrom/demo/demo.S
new file mode 100644
index 0000000..c6f2618
--- /dev/null
+++ b/bootrom/demo/demo.S
@@ -0,0 +1,71 @@
+#define UART_BASE 0x48000000
+#define SPI_BASE 0x48001000
+#define GPIO_BASE 0x48002000
+
+#ifndef CFG_STRING
+#error Must define CFG_STRING
+#endif
+
+ .globl _start
+_start:
+ j uart_init
+ nop
+ nop
+ .word cfgstr
+
+uart_init:
+ // a1 = UART_TX
+ // a2 = hello_msg_end
+ // for (a0 = hello_msg_start; a0 != a2; ++ a0){
+ // while (a3 = TX_READY == 0);
+ // a3 = *a0
+ // *a1 = a3
+ // }
+
+ la a0, hello_msg_start
+ la a2, hello_msg_end
+ li a1, UART_BASE
+
+uart_loop:
+ lw a3, 4(a1) // Wait until non-zero (uart can send data).
+ beqz a3, uart_loop
+
+ lb a3, 0(a0) // read the next character in hello_msg
+ sw a3, 0(a1) // Write the current character.
+ addi a0, a0, 1 // increment the pointer.
+ bne a0, a2, uart_loop
+
+gpio_init:
+ li a0, GPIO_BASE
+ li t0, 0xFFFF0000
+ sw t0, 4(a0)
+
+gpio_loop:
+ // For Red LEDs, increment manually.
+ li t0, 0x1
+ sw t0, (a0)
+ li t0, 0x2
+ sw t0, (a0)
+ li t0, 0x4
+ sw t0, (a0)
+ li t0, 0x8
+ sw t0, (a0)
+
+ // For Blue and Green LEDs, sample the switches & buttons
+
+ lw t0, (a0)
+ srli t0, t0, 16
+ andi t0, t0, 0xFF
+ slli t0, t0, 4
+ sw t0, (a0)
+
+ j gpio_loop
+
+ .section .rodata
+
+hello_msg_start:
+ .incbin "hello_msg.txt"
+hello_msg_end:
+
+cfgstr:
+ .incbin CFG_STRING
diff --git a/bootrom/demo/hello_msg.txt b/bootrom/demo/hello_msg.txt
new file mode 100644
index 0000000..c3cb3f2
--- /dev/null
+++ b/bootrom/demo/hello_msg.txt
@@ -0,0 +1,37 @@
+
+ SIFIVE, INC.
+
+ 5555555555555555555555555
+ 5555 5555
+ 5555 5555
+ 5555 5555
+ 5555 5555555555555555555555
+ 5555 555555555555555555555555
+ 5555 5555
+ 5555 5555
+ 5555 5555
+5555555555555555555555555555 55555
+ 55555 555555555 55555
+ 55555 55555 55555
+ 55555 5 55555
+ 55555 55555
+ 55555 55555
+ 55555 55555
+ 55555 55555
+ 55555 55555
+ 555555555
+ 55555
+ 5
+
+ SiFive RISC-V Coreplex
+
+Welcome to the Arty FPGA Freedom E Dev Kit.
+The red LEDs are blinking very fast and appear
+dim. Try pressing the buttons and switches to control
+the blue and green LEDs. You can try using the
+debugger to step through the boot code.
+
+
+
+
+