Simple debug logging via USART1

Encapsulates the #define macros and AVR implementation of dumping strings
(RAM and PROGMEM) onto USART1.

src/CMakeLists.txt

@@ -1,4 +1,4 @@
-target_sources(firmware PRIVATE main.cpp)
+target_sources(firmware PRIVATE main.cpp debug.cpp)
 
 target_link_libraries(firmware LUFA)
 

src/debug.cpp

@@ -0,0 +1,36 @@
+#include "debug.h"
+
+#if defined(DEBUG_LOGIC) || defined(DEBUG_MODULES) || defined(DEBUG_HAL)
+
+#include "hal/usart.h"
+#include <avr/pgmspace.h>
+#include <stdio.h>
+#include <string.h>
+
+namespace debug {
+
+#ifdef DEBUG_LOGIC
+const char logic[] PROGMEM = "log:";
+#endif
+
+#ifdef DEBUG_MODULES
+const char modules[] PROGMEM = "mod:";
+#endif
+
+#ifdef DEBUG_HAL
+const char hal[] PROGMEM = "hal:";
+#endif
+
+void dbg_usart(const char *layer_P, const char *s) {
+    hu::usart1.puts_P(layer_P);
+    hu::usart1.puts(s);
+}
+
+void dbg_usart_P(const char *layer_P, const char *s_P) {
+    hu::usart1.puts_P(layer_P);
+    hu::usart1.puts_P(s_P);
+}
+
+} // namespace debug
+
+#endif

src/debug.h

@@ -0,0 +1,55 @@
+#pragma once
+#include <stdint.h>
+
+/// Enable DEBUG_LOGIC to compile debugging and error messages (beware of code base size ;) ) for the logic layer
+#define DEBUG_LOGIC
+
+/// Enable DEBUG_LOGIC to compile debugging and error messages (beware of code base size ;) ) for the logic layer
+#define DEBUG_MODULES
+
+/// Enable DEBUG_HAL to compile debugging and error messages (beware of code base size ;) ) for the logic layer
+#define DEBUG_HAL
+
+/// Debugging macros and tools
+namespace debug {
+
+#ifdef DEBUG_LOGIC
+extern const char logic[];
+#define dbg_logic(x) debug::dbg_usart(debug::logic, x)
+#define dbg_logic_P(x) debug::dbg_usart_P(debug::logic, x)
+#else
+#define dbg_logic(x) /* */
+#define dbg_logic_P(x) /* */
+#endif
+
+#ifdef DEBUG_MODULES
+extern const char modules[];
+#define dbg_modules(x) debug::dbg_usart(debug::modules, x)
+#define dbg_modules_P(x) debug::dbg_usart_P(debug::modules, x)
+#else
+#define dbg_modules(x) /* */
+#define dbg_modules_P(x) /* */
+#endif
+
+#ifdef DEBUG_HAL
+extern const char hal[];
+#define dbg_hal(x) debug::dbg_usart(debug::hal, x)
+#define dbg_hal_P(x) debug::dbg_usart_P(debug::hal, x)
+#else
+#define dbg_hal(x) /* */
+#define dbg_hal_P(x) /* */
+#endif
+
+#if defined(DEBUG_LOGIC) || defined(DEBUG_MODULES) || defined(DEBUG_HAL)
+/// Dump an error message onto the USART
+/// @param layer PROGMEM string
+/// @param s RAM string to be printed
+void dbg_usart(const char *layer_P, const char *s);
+
+/// Dump an error message onto the USART
+/// @param layer PROGMEM string
+/// @param s PROGMEM string to be printed
+void dbg_usart_P(const char *layer_P, const char *s_P);
+#endif
+
+} // namespace debug

src/hal/avr/usart.cpp

@@ -1,5 +1,6 @@
 #include "../usart.h"
 #include <avr/interrupt.h>
+#include <avr/pgmspace.h>
 
 namespace hal {
 namespace usart {
@@ -70,6 +71,13 @@ void USART::puts(const char *str) {
     }
 }
 
+void USART::puts_P(const char *str) {
+    char c;
+    while ((c = pgm_read_byte(*str++)) != 0) {
+        Write(c);
+    }
+}
+
 } // namespace usart
 } // namespace hal
 

src/hal/usart.h

@@ -46,7 +46,11 @@ public:
     /// @param c character to be pushed into the TX buffer (to be sent)
     void Write(uint8_t c);
     /// @param str c string to be sent. NL is appended
+    /// Works on RAM strings
     void puts(const char *str);
+    /// @param str c string to be sent. NL is appended
+    /// Works on PROGMEM strings
+    void puts_P(const char *str);
     /// @returns true if there is at least one byte free in the TX buffer (i.e. some space to add a character to be sent)
     bool CanWrite() const {
         return !tx_buf.full();