Debug

For Debugging Only

These methods provide a simple way to print text and numbers to the screen, but they are not intended for building a user interface. They draw directly to the video memory, so you must call LCD_Refresh() to see any output.

For final applications, please consider using proper GUI elements instead of Debug_Printf.

Check the updated Usage and the source SDK code.

Overview

The debug methods allow you to print text and numbers on a simple character grid. Some functions use an internal cursor, which can be set with Debug_SetCursorPosition. The units are character cells, not pixels, so setting the cursor to (1,1) refers to the second character on the second line.

Other functions, like Debug_Printf, bypass the cursor at (1,1) means the second line second character.

Methods

Cursor Position

int Debug_SetCursorPosition(unsigned int x, unsigned int y);
void Debug_GetCursorPosition(unsigned int *x, unsigned int *y);

x and y are the position of the internal text cursor. Debug_PrintString will print text starting at this location.

Print String

bool Debug_PrintString(const char *string, bool invert);

Prints a string at the current cursor position. The invert parameter controls the color scheme: false for black-on-white, true for white-on-black.

Print Advanced String

void Debug_Printf(unsigned int x, unsigned int y, bool invert, int zero, const char *format, ...);

Prints a formatted string at the specified character coordinates (x, y), ignoring the internal cursor. The zero parameter must always be 0.

Supports most format specifiers:

• %s for strings
• %d for integers
• %x for hexadecimal

Print Hex Numbers

void Debug_PrintNumberHex_Nibble(uint8_t value, unsigned int x, unsigned int y);
void Debug_PrintNumberHex_Byte(uint8_t value, unsigned int x, unsigned int y);
void Debug_PrintNumberHex_Word(uint16_t value, unsigned int x, unsigned int y);
void Debug_PrintNumberHex_Dword(uint32_t value, unsigned int x, unsigned int y);

Prints the hexadecimal representation of a number at the specified coordinates (x, y).

• nibble: 4-bit number
• byte: 8-bit number
• word: 16-bit number
• dword: 32-bit number

Wait for a Key

int Debug_WaitKey();

Waits until a key is pressed, then returns a number representing the key. It primarily reacts to number keys (returning 0x30-0x39) and the Power/Clear key (returning 0x98).

Behaviour Change

With HH3, it also returns on touch events.

More details about its return and behavior in the SDK source code

Usage

#include <sdk/os/debug.h>
#include <sdk/os/lcd.h>

// Print "Hello, world!" at (0, 0) in black on white
Debug_SetCursorPosition(0, 0);
Debug_PrintString("Hello, world!", false);

// Print "Inverted text" at (1, 1) in white on black
Debug_SetCursorPosition(1, 1);
Debug_PrintString("Inverted text", true);

// Print the hex number 0x1322 at coordinates (3, 7) directly
Debug_PrintNumberHex_Word(0x1322, 3, 7);

// Print small text with a format string
Debug_Printf(10, 10, false, 0, "Just one number : %d", 42);
Debug_Printf(20, 20, false, 0, "Format are still %s in %d!", "cool", 2025);

// Draw the changes we made to VRAM onto the LCD
LCD_Refresh();

// Block until the user presses a key
Debug_WaitKey();