;;********************************************************************************
;; @module keyboard 
;; @type drive
;; @details:
;;  Support for a PS2 Keyboard using the shift register of a 6522 VIA
;;  Pressing a key causes 11 bits to be sent: 1 start - 8 scancode - 1 parity - 1 stop 
;;  The VIA is set up to interrupt after 8 bits have been shifted into the shift register
;;  from the external clock pulses of the keyboard (additional hardware required to 
;;  address the hardware bug of the VIA, where bit get lost when the external clock 
;;  transition happens during falling edge of PHI2). After reading the shift register,
;;  the VIAs T2 timer is set to interrupt after the last 3 bits have been shifted in,
;;  which takes about ~230ms.
;;********************************************************************************
.ifndef INCLUDE_KEYBOARD
INCLUDE_KEYBOARD = 1
.include "system.h65"

.scope kb
Import kb,init,irq_shift_reg_handler,irq_timer_handler,scancode,key_read
Import kb, CHARS_NOMOD, CHARS_MODSHIFT
ImportZp kb,status
KB_IO = IO1

.enum STATUS
    RELEASE			= %10000000
    TWOBYTE 		= %01000000
    SHIFT   		= %00100000
    CAPSLOCK		= %00010000
    CAPSLOCK_HELD	= %00000010
    RIGHTALT		= %00001000
    NUMLOCK 		= %00000100
.endenum

K_TWOBYTE			= $E0
K_RELEASE			= $F0

.enum K
	F9              = $01
	F5              = $03
	F3              = $04
	F1              = $05
	F2              = $06
	F12             = $07
	F10             = $09
	F8              = $0A
	F6              = $0B
	F4              = $0C
	TAB             = $0D
	GRAVE           = $0E
	LEFTALT         = $11
	LEFTSHIFT       = $12
	LEFTCTRL        = $14
	K_Q             = $15
	K_1             = $16
	K_Y             = $1A
	K_S             = $1B
	K_A             = $1C
	K_W             = $1D
	K_2             = $1E
	K_C             = $21
	K_X             = $22
	K_D             = $23
	K_E             = $24
	K_4             = $25
	K_3             = $26
	SPACE           = $29
	K_V             = $2A
	K_F             = $2B
	K_T             = $2C
	K_R             = $2D
	K_5             = $2E
	K_N             = $31
	K_B             = $32
	K_H             = $33
	K_G             = $34
	K_Z             = $35
	K_6             = $36
	K_M             = $3A
	K_J             = $3B
	K_U             = $3C
	K_7             = $3D
	K_8             = $3E
	COMMA           = $41
	K_K             = $42
	K_I             = $43
	K_O             = $44
	K_0             = $45
	K_9             = $46
	DOT             = $49
	DASH            = $4A
	K_L             = $4B
	OUML            = $4C
	K_P             = $4D
	SSHARP          = $4E
	AUML            = $52
	UUML            = $54
	BACKTICK        = $55
	CAPSLOCK        = $58
	RIGHTSHIFT      = $59
	ENTER           = $5A
	PLUS            = $5B
	HASH            = $5D
	LESSTHAN        = $61
	BACKSPACE       = $66
	KP1             = $69
	KP4             = $6B
	KP7             = $6C
	KP0             = $70
	KPDOT           = $71
	KP2             = $72
	KP5             = $73
	KP6             = $74
	KP8             = $75
	ESCAPE          = $76
	NUMLOCK         = $77
	F11             = $78
	KPPLUS          = $79
	KP3             = $7A
	KPMINUS         = $7B
	KPASTERISK      = $7C
	KP9             = $7D
	SCROLLLOCK      = $7E
	F7              = $83
.endenum

.enum K2
	RIGHTALT        = $11
	RIGHTCTRL       = $14
	LEFTMETA        = $1F
	RIGHTMETA       = $27
	MENU            = $2F
	BREAK           = $37
	SYSRQ           = $3F
	KPDIVIDE        = $4A
	KPENTER         = $5A
	END             = $69
	LEFT            = $6B
	POS1            = $6C
	INSERT          = $70
	DELETE          = $71
	DOWN            = $72
	RIGHT           = $74
	UP              = $75
	PAGEDOWN        = $7A
	PAGEUP          = $7D
.endenum


.endscope

.endif  ; guard