bricks/nxt: Run an .mpy file from flash.

Similar to how it is done on the other hubs.

Allow basic debugging in one step:
Make, flash, boot, run mpy, reset, repeat.

Author: laurensvalk

bricks/nxt/Makefile

@@ -39,6 +39,8 @@ QSTR_GLOBAL_DEPENDENCIES =
 # MicroPython feature configurations
 MICROPY_ROM_TEXT_COMPRESSION ?= 1
 
+MPY_CROSS_FLAGS += -mno-unicode
+
 # include py core make definitions
 include $(TOP)/py/py.mk
 
@@ -230,6 +232,16 @@ OBJ += $(addprefix $(BUILD)/, $(PBIO_SRC_C:.c=.o))
 OBJ += $(addprefix $(BUILD)/, $(PYBRICKS_PYBRICKS_SRC_C:.c=.o))
 OBJ += $(addprefix $(BUILD)/, $(CONTIKI_SRC_C:.c=.o))
 OBJ += $(addprefix $(BUILD)/, $(LIBFIXMATH_SRC_C:.c=.o))
+OBJ += $(BUILD)/main.mpy.o
+
+$(BUILD)/main.mpy: main.py
+	$(ECHO) "MPY $<"
+	$(Q)$(MPY_CROSS) -o $@ $(MPY_CROSS_FLAGS) $<
+	$(ECHO) "`wc -c < $@` bytes"
+
+$(BUILD)/main.mpy.o: $(BUILD)/main.mpy
+	$(Q)$(OBJCOPY) -I binary -O elf32-littlearm -B arm \
+		--rename-section .data=.mpy,alloc,load,readonly,data,contents $^ $@
 
 # List of sources for qstr extraction
 SRC_QSTR += $(SRC_C) $(PYBRICKS_PYBRICKS_SRC_C)
@@ -242,9 +254,10 @@ $(BUILD)/firmware.elf: $(LDSCRIPT) $(OBJ)
 	$(ECHO) "LINK $@"
 	$(Q)$(LD) $(LDFLAGS) -o $@ $(OBJ) $(LIBS)
 
+# firmware blob with main.mpy - can be flashed to hub
 $(BUILD)/firmware.bin: $(BUILD)/firmware.elf
 	$(ECHO) "BIN creating firmware file"
-	$(Q)$(OBJCOPY) -O binary $< $@
+	$(Q)$(OBJCOPY) -O binary -j .isr_vector -j .text -j .data -j .name -j .user $^ $@
 	$(ECHO) "`wc -c < $@` bytes"
 
 include $(TOP)/py/mkrules.mk

bricks/nxt/main.c

@@ -20,6 +20,7 @@
 #include "py/gc.h"
 #include "py/mperrno.h"
 #include "py/persistentcode.h"
+#include "py/stackctrl.h"
 #include "lib/utils/pyexec.h"
 #include "lib/utils/interrupt_char.h"
 
@@ -80,7 +81,7 @@ void nxt_init() {
     udp_init();
     systick_wait_ms(100);
     sound_freq(500, 100, 30);
-    systick_wait_ms(1000);
+    systick_wait_ms(100);
     display_init();
     sp_init();
     display_set_auto_update_period(DEFAULT_UPDATE_PERIOD);
@@ -102,7 +103,10 @@ void nxt_deinit() {
     shutdown(1);
 }
 
-static char *stack_top;
+// defined in linker script
+extern uint32_t _estack;
+extern uint32_t __bss_end__;
+
 #if MICROPY_ENABLE_GC
 static char heap[PYBRICKS_HEAP_KB * 1024];
 #endif
@@ -143,20 +147,21 @@ static const pbsys_user_program_callbacks_t user_program_callbacks = {
     .stdin_event = user_program_stdin_event_func,
 };
 
+// Defined in linker script
+extern uint32_t _pb_user_mpy_size;
+extern uint8_t _pb_user_mpy_data;
+
 int main(int argc, char **argv) {
-    int stack_dummy;
-    stack_top = (char *)&stack_dummy;
 
     pbio_init();
     nxt_init();
 
+    mp_stack_set_top(&_estack);
+    mp_stack_set_limit((char *)&_estack - (char *)&__bss_end__ - 1024);
+
     #if MICROPY_ENABLE_GC
     gc_init(heap, heap + sizeof(heap));
     #endif
-
-    // (re)boot message
-    mp_print_str(&mp_plat_print, "Pybricks\n");
-
     // Get system hardware ready
     pbsys_user_program_prepare(&user_program_callbacks);
     // make sure any pending events are handled before starting MicroPython
@@ -167,11 +172,29 @@ int main(int argc, char **argv) {
     mp_init();
 
     // Run a program
-    // TODO
+    nlr_buf_t nlr;
+    if (nlr_push(&nlr) == 0) {
+        // run user .mpy file
+        mp_reader_t reader;
+        mp_reader_new_mem(&reader, &_pb_user_mpy_data, _pb_user_mpy_size, 0);
+        mp_raw_code_t *raw_code = mp_raw_code_load(&reader);
+        mp_obj_t module_fun = mp_make_function_from_raw_code(raw_code, MP_OBJ_NULL, MP_OBJ_NULL);
+        mp_hal_set_interrupt_char(3);
+        mp_call_function_0(module_fun);
+        mp_hal_set_interrupt_char(-1);
+        mp_handle_pending(true);
+        nlr_pop();
+    } else {
+        // uncaught exception
+        mp_hal_set_interrupt_char(-1); // disable interrupt
+        mp_handle_pending(false); // clear any pending exceptions (and run any callbacks)
+
+        pbsys_user_program_unprepare();
+        mp_obj_print_exception(&mp_plat_print, (mp_obj_t)nlr.ret_val);
+    }
 
     // Uninitialize MicroPython and the system hardware
     mp_deinit();
-    pbsys_user_program_unprepare();
 
     nxt_deinit();
     return 0;

bricks/nxt/main.py

@@ -0,0 +1,13 @@
+from pybricks.tools import wait
+from pybricks.nxtdevices import Motor
+from pybricks.parameters import Port
+
+motor = Motor(Port.A)
+
+print("1")
+
+motor.dc(50)
+wait(1000)
+motor.stop()
+
+print("2")

bricks/nxt/mpconfigport.h

@@ -19,7 +19,7 @@
 #define PYBRICKS_PY_COMMON_SYSTEM       (1)
 #define PYBRICKS_PY_EXPERIMENTAL        (0)
 #define PYBRICKS_PY_GEOMETRY            (0)
-#define PYBRICKS_PY_HUBS                (1)
+#define PYBRICKS_PY_HUBS                (0)
 #define PYBRICKS_PY_MEDIA               (0)
 #define PYBRICKS_PY_NXTDEVICES          (1)
 #define PYBRICKS_PY_PARAMETERS          (1)
@@ -49,6 +49,7 @@
 #define MICROPY_DEBUG_PRINTERS      (0)
 #define MICROPY_ENABLE_GC           (1)
 #define MICROPY_GC_ALLOC_THRESHOLD  (0)
+#define MICROPY_STACK_CHECK         (1)
 #define MICROPY_REPL_EVENT_DRIVEN   (0)
 #define MICROPY_HELPER_REPL         (1)
 #define MICROPY_HELPER_LEXER_UNIX   (0)
@@ -89,6 +90,9 @@
 #define MICROPY_ENABLE_SCHEDULER    (0)
 #define MICROPY_PY_INSTANCE_ATTRS   (1)
 
+#define MICROPY_PERSISTENT_CODE_LOAD    (1)
+#define MICROPY_ENABLE_EXTERNAL_IMPORT  (0)
+
 // type definitions for the specific machine
 
 #define MICROPY_MAKE_POINTER_CALLABLE(p) ((void *)((mp_uint_t)(p) | 1))

bricks/nxt/nxt.ld

@@ -51,12 +51,24 @@ SECTIONS {
   __bss_start__ = ADDR(.bss);
   __bss_end__   = ADDR(.bss) + SIZEOF(.bss);
 
-  .stack (NOLOAD) : {
-    *(.stack .stack.*)
+  .stack :
+  {
+      . = ALIGN(4);
+      . = . + 4K; /* will cause linker error if there is not enough space for stack. */
+      . = ALIGN(4);
   } >RAM
 
   _estack = ADDR(.stack) + SIZEOF(.stack);
 
+  .user :
+  {
+      . = ALIGN(4);
+      _pb_user_mpy_size = .;
+      LONG(SIZEOF(.user) - (. + 4 - LOADADDR(.user))); /* Size of compiled main.mpy file in bytes */
+      _pb_user_mpy_data = .;
+      KEEP(*(.mpy));       /* Compiled main.mpy file */
+  } >ROM
+
   __free_ram_start__ = ALIGN(ADDR(.stack) + SIZEOF(.stack), 16);
   __free_ram_end__   = ORIGIN(RAM) + LENGTH(RAM);
 }