Add a target to the Makefile to directly program the FPGA (#450)

Makefile

@@ -201,6 +201,9 @@ vivado-fpga:
 vivado-fpga-nobuild:
 	$(FUSESOC) --cores-root . run --no-export --target=$(FPGA_BOARD) $(FUSESOC_FLAGS) --setup openhwgroup.org:systems:core-v-mini-mcu ${FUSESOC_PARAM} 2>&1 | tee buildvivado.log
 
+vivado-fpga-pgm:
+	$(MAKE) -C build/openhwgroup.org_systems_core-v-mini-mcu_0/$(FPGA_BOARD)-vivado pgm
+
 ## @section ASIC
 ## Note that for this step you need to provide technology-dependent files (e.g., libs, constraints)
 asic:

README.md

@@ -524,7 +524,19 @@ To program the bitstream, open Vivado,
 open --> Hardware Manager --> Open Target --> Autoconnect --> Program Device
 ```
 
-and choose the file `openhwgroup.org_systems_core-v-mini-mcu_0.bit`
+and choose the file `openhwgroup.org_systems_core-v-mini-mcu_0.bit`.
+
+Or simply type:
+
+```
+bash vivado-fpga-pgm FPGA_BOARD=pynq-z2
+```
+
+or
+
+```
+make vivado-fpga-pgm FPGA_BOARD=nexys-a7-100t
+```
 
 To run SW, follow the [Debug](./Debug.md) guide
 to load the binaries with the HS2 cable over JTAG,