Solved
Missing ESC key code in USB HID_KEYBRD_Key table array
The Escape key was mapped to 0x00 in the USB HID code, I added it and it works fine but I'm curious to know why it was absent? Bug/oversight, another method used for Escape key detection?
#ifdef QWERTY_KEYBOARD
static const uint8_t HID_KEYBRD_Key[] =
{
'\0', '`', '1', '2', '3', '4', '5', '6',
'7', '8', '9', '0', '-', '=', '\0', '\r',
'\t', 'q', 'w', 'e', 'r', 't', 'y', 'u',
'i', 'o', 'p', '[', ']', '\\',
'\0', 'a', 's', 'd', 'f', 'g', 'h', 'j',
'k', 'l', ';', '\'', '\0', '\n',
'\0', '\0', 'z', 'x', 'c', 'v', 'b', 'n',
'm', ',', '.', '/', '\0', '\0',
'\0', '\0', '\0', ' ', '\0', '\0', '\0', '\0',
'\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
'\0', '\0', '\0', '\0', '\0', '\r', '\0', '\0',
'\0', '\0', '\0', '\0', '\0', '\0',
'\0', '\0', '7', '4', '1',
'\0', '/', '8', '5', '2',
'0', '*', '9', '6', '3',
'.', '-', '+', '\0', '\n', '\0', '\e', '\0', '\0', '\0', '\0', /* Modification - changed \0 to \e for Escape key detection */
'\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
'\0', '\0', '\0', '\0'
};