Added GPIO example and block design docs.

README.md

@@ -0,0 +1,18 @@
+# Hello world example for Flute
+
+This project contains a working project for Bluespec's open source 'Flute' processor.
+
+## How to build?
+
+```bash
+mkdir build && cd build
+TOOLCHAIN_PATH=${MY_RV_TOOLCHAIN_PATH} cmake DCMAKE_TOOLCHAIN_FILE=riscv64-unknown-eabi.cmake ..
+make
+
+```
+
+## Hardware
+
+The Vivado project and bluespec bsv sources will be uploaded in a few days.
+
+![Vivado block design](assets/images/block_design.png)

src/main.c

@@ -22,10 +22,13 @@ int main(int argc, char *argv[]) {
 
     printf("System clock frequency: %luHz\r\n", SYS_CLK_FREQ);
 
+    xilinx_gpio_pinmode(&soc_gpio, 0, 1);
+
     for(;;) {
-        System_Delay(10000);
+        System_Delay(500);
         __csrr("mcycle", csr);
         printf("mcycle: 0x%016llx\r\n", csr);
+        xilinx_gpio_toggle(&soc_gpio, 0);
     }
 
     return 0;