microwatt_tutorial: Added section on Micropython.

diff --git a/HDL_workflow/microwatt_tutorial.mdwn b/HDL_workflow/microwatt_tutorial.mdwn
index bba65aecbbdaf9a5710355190a583741373b420f..d12d3b4cfccefe29a0a7f5dd15f24e2582c30744 100644 (file)
--- a/HDL_workflow/microwatt_tutorial.mdwn
+++ b/HDL_workflow/microwatt_tutorial.mdwn
@@ -177,6 +177,37 @@ allowing you to look at processor signals and transitions during simulation.
     (microwatt):$ vcd2fst --vcdname=microwatt-verilator.vcd --fstname=microwatt-verilator.fst
     (microwatt):$ gtkwave microwatt-verilator.fst
 
+## Micropython
+
+The microwatt repo comes witha pre-compiled micropython binary (version 1.12),
+which you can try out after confirming 'hello world' works. Bear in mind, not
+all features of python will be available. Such as floating-point numbers.
+
+For micropython to work, you'll need to increase the RAM size in the makefile.
+Go to the microwatt-verilator makefile, and comment out the following lines:
+
+    MEMORY_SIZE=8192
+    RAM_INIT_FILE=hello_world/hello_world.hex
+
+And uncomment the following:
+
+    MEMORY_SIZE=393216
+    RAM_INIT_FILE=micropython/firmware.hex
+
+This will increase the RAM size from 8KiB to 384KiB. The `RAM_INIT_FILE` in
+these examples isn't doing anything, however good practice to follow.
+
+Clean up generated files, and recompile:
+
+    make clean
+    make microwatt-verilator
+
+Once the binary has been built, run the same way as before, but point to the
+micropython firmware binary:
+
+    microwatt-verilator micropython/firmware.bin
+
+
 
 ## Verilator runtime commands
 A few examples: