de0_nano: Update the tutorial to be step by step

Author: stffrdhrn

de0_nano/index.md

@@ -60,29 +60,53 @@ cd /tmp/or1k-de0nano
 curl -L -O https://openrisc.io/tutorials/sw/hello/hello.c
 curl -L -O https://openrisc.io/tutorials/sw/timer/timer.c
 
+CFLAGS="-mboard=de0_nano -DDE0_NANO"
+or1k-elf-gcc -g -Og $CFLAGS -o hello.elf hello.c
+or1k-elf-gcc -g -Og $CFLAGS -o timer.elf timer.c
+
+# Add IP cores to the environment
+fusesoc library add fusesoc-cores https://github.com/fusesoc/fusesoc-cores
+fusesoc library add elf-loader https://github.com/fusesoc/elf-loader.git
+fusesoc library add openrisc-cores https://github.com/openrisc/openrisc-cores
 fusesoc library add de0_nano https://github.com/olofk/de0_nano.git
+
+# Check the SoC is available
+fusesoc core show de0_nano
 ```
 
 ### Build the FPGA bitstream
 
 ```bash
-fusesoc build de0_nano
+fusesoc run de0_nano
 ```
 
+The FuseSoC `run` command will run the default target, for `de0_nano` this is
+synthesis using the tool `quartus`.  You could also specify this using `fusesoc
+run --target synth --tool quartus de0_nano`.  The `run` command has 3 phases:
+
+  * **setup** - Creates the project directories and project files
+  * **build** - Builds the artifacts, for quartus this means the FPGA bitstream.
+  * **run** - Runs the SoC, this will perform programming, but by default this is disabled.
+
 ### Program the FPGA bitstream
 
-Once the board is setup, you can download the FPGA bitstream by
-running
+Once the board is setup and built, you can download the FPGA bitstream by
+running the following:
 
 ```bash
-fusesoc pgm de0_nano
+fusesoc run --run de0_nano --pgm quartus
 ```
 
+Passing the `--run` argument allows only the run stage to be run. This is useful
+as we do not want to build the entire project again.  Passing `--pgm quartus`
+enables the run stage to use `quartus_pgm` to program the bitstream to fpga
+board.
+
 ### Start the OpenOCD daemon
 
 In one terminal execute the following command:
 
-	openocd -s ${OPENOCD}/share/openocd/scripts/ -f interface/altera-usb-blaster.cfg -f ../or1k-dev.tcl 
+	openocd -s ${OPENOCD}/share/openocd/scripts/ -f interface/altera-usb-blaster.cfg -f ../or1k-dev.tcl
 
 ### Run software with gdb
 
@@ -99,23 +123,3 @@ In gdb execute the following steps:
 	continue
 
 You should see the LEDs counting and UART output once a second.
-
-## (Re-)build the hardware
-
-You can rebuilt the hardware by running:
-
-```bash
-fusesoc build de0_nano
-```
-
-## (Re-)build the software
-
-Some example software is available, that you can (re-)build for the
-DE0 nano board by running
-
-```bash
-CFLAGS=-mboard=de0_nano -DDE0_NANO
-
-or1k-elf-gcc -g -o hello.elf ${CFLAGS} ../sw/hello/hello.c
-or1k-elf-gcc -g -o timer.elf ${CFLAGS} ../sw/timer/timer.c
-```