gistfile1.txt

		.global		_c_int00	;This assembler directive allows _c_int00 to be a
								;global variable. This tells the linker where your
								;program (.text code) begins and where to boot from.

;***************************** Program Constants ****************************************
; Creating constants using the .set assembler directive. This should be at the top of your
; program.  This is like a define statement in C.
data_sect	    .set	0xa000			;constant that is actually the starting addr of .data section
bss_sect	    .set	0xb000			;constant that is actually the starting addr of .bss section
gpamux			.set	0x6f86
gpadir		 	.set	0x6f8a
gpadat		 	.set	0x6fc0

gpbmux			.set    0x6F96
gpcmux			.set	0x6FA6
pclkcr3			.set	0x7020

;****************************************************************************************

;******************* DATA ALLOCATION SECTION - Variables/Data ***************************
; Data can go before or after your program code but should not be placed in the middle
; nof a program for clarity reasons.
		.data				;data section, see the command linker file, this puts the
							;following data defined below in a block of internal SRAM
							;starting at 0xA000.
key_pressed		.word	0xff
count			.word	0

;****************************************************************************************

		.text			;Program section, see the command linker file, program code
						;should be placed in the text section which starts at 0x9000

_c_int00:				;This label tells the linker where the entry (starting) point for
						;the first instruction in your program.

s		EALLOW

		PUSH DP
		SETC OBJMODE ;allow 32 bit mov instructions
		MOVZ DP,#0x7029>>6 ;turn off that pesky watchdog timer
		MOV @7029h,#0x68
		POP DP

		MOV		AR0,#gpbmux
		MOV 	*AR0,#0x3C0		;Enable R/W and CS0

		MOV		AR0,#gpcmux
		MOV		*AR0,#0xffff
		MOV 	AR0,#gpcmux+1
		MOV		*AR0,#0xffff	;Enable data7:0

		MOV		AR0,#pclkcr3	;Enable CS0
		MOV		*AR0,#0x1000

		MOV 	AR0,#gpamux
		MOV		*AR0,#0
		INC		AR0
		MOV		*AR0,#0
		INC		AR0
		MOV 	*AR0,#0
		INC		AR0
		MOV		*AR0,#0			;Setting GPAMUX1/2 to 0


		MOV		AR0,#gpadir
		MOV		*AR0,#0x00ff	;Keypad column read/switchs/leds
		INC		AR0
		MOV		*AR0,#0x1f		;Keypad row write

		MOV		AR0,#gpadat
		MOV		AR1,#gpadat+1
		MOV		AR3,#key_pressed
		MOV		AR4,#count
		MOV		AR5,#0x4000

		MOV		*AR0,#0xff		;Initial clear

LOOP	LC		CHECK
		B		LOOP,UNC


CHECK	MOV		AR2,#0xff
		MOV		*AR1,#0x7	;Put 7
		NOP
		NOP
		NOP
		NOP
		NOP
		NOP
		MOV		AL,*AR0
		LSR		AL,#12

		MOV		AH,#0x7		;Checking for 7
		MOV		AR2,#0x1
		CMP		AH,AL
		B		GEN_RET,EQ

		MOV		AH,#0xB		;Checking for B
		MOV		AR2,#0x2
		CMP		AH,AL
		B		GEN_RET,EQ

		MOV		AH,#0xD		;Checking for D
		MOV		AR2,#0x3
		CMP		AH,AL
		B		GEN_RET,EQ

		MOV		AH,#0xE		;Checking for E
		MOV		AR2,#0xA
		CMP		AH,AL
		B		GEN_RET,EQ

		MOV		*AR1,#0xb	;Put B
		NOP
		NOP
		NOP
		NOP
		NOP
		NOP
		MOV		AL,*AR0
		LSR		AL,#12

		MOV		AH,#0x7		;Checking for 7
		MOV		AR2,#0x4
		CMP		AH,AL
		B		GEN_RET,EQ

		MOV		AH,#0xB		;Checking for B
		MOV		AR2,#0x5
		CMP		AH,AL
		B		GEN_RET,EQ

		MOV		AH,#0xD		;Checking for D
		MOV		AR2,#0x6
		CMP		AH,AL
		B		GEN_RET,EQ

		MOV		AH,#0xE		;Checking for E
		MOV		AR2,#0xB
		CMP		AH,AL
		B		GEN_RET,EQ

		MOV		*AR1,#0xd	;Put D
		NOP
		NOP
		NOP
		NOP
		NOP
		NOP
		MOV		AL,*AR0
		LSR		AL,#12

		MOV		AH,#0x7		;Checking for 7
		MOV		AR2,#0x7
		CMP		AH,AL
		B		GEN_RET,EQ

		MOV		AH,#0xB		;Checking for B
		MOV		AR2,#0x8
		CMP		AH,AL
		B		GEN_RET,EQ

		MOV		AH,#0xD		;Checking for D
		MOV		AR2,#0x9
		CMP		AH,AL
		B		GEN_RET,EQ

		MOV		AH,#0xE		;Checking for E
		MOV		AR2,#0xc
		CMP		AH,AL
		B		GEN_RET,EQ

		MOV		*AR1,#0xe	;Put E
		NOP
		NOP
		NOP
		NOP
		NOP
		NOP
		MOV		AL,*AR0
		LSR		AL,#12

		MOV		AH,#0x7		;Checking for 7
		MOV		AR2,#0xe
		CMP		AH,AL
		B		GEN_RET,EQ

		MOV		AH,#0xB		;Checking for B
		MOV		AR2,#0x0
		CMP		AH,AL
		B		GEN_RET,EQ

		MOV		AH,#0xD		;Checking for D
		MOV		AR2,#0xf
		CMP		AH,AL
		B		GEN_RET,EQ

		MOV		AH,#0xE		;Checking for E
		MOV		AR2,#0xd
		CMP		AH,AL
		B		GEN_RET,EQ

		MOV		AR2,#0xff

;AR0 -> GPADAT
;AR2 -> value pressed (or ff if none pressed)
;AR3 -> *key_pressed
;AR4 -> *count
GEN_RET	LC		DELAY
		MOV		AH,*AR3
		MOV		AL,AR2
		CMP		AH,AL
		B		EZRET,EQ	;If current value is same as last, return
		MOV		*AR3,AL		;Otherwise move current pressed into memory, we still
							;have the old one in AH
		MOV		AR7,AH		;Temporarily put old pressed in AR7
		MOV		AH,#0xff
		CMP		AH,AL		;If current value is 0xff, we know we have a key lift
		B		DOINC,EQ
		LRET

DOINC	MOV		AH,AR7		;Put old back in AH, it's the real value
		MOV		AL,#0
		CMP		AH,AL
		B		DOCLEAR,EQ
		MOV		AL,*AR4
		ADD		AH,AL
		MOV		*AR4,AH
		MOV		*AR5,AH
		NOT		AH
		MOV		*AR0,AH
		LRET

DOCLEAR	MOV		*AR4,#0
		MOV		*AR0,#0xff
		MOV		*AR5,#0
		LRET

;Delays a lot, clobbers AL
DELAY	MOV		AL,#0x3FFF
		MOV		*AR1,#0x10
DELAYI	DEC		AL
		B		DELAYI,NEQ
		MOV		*AR1,#0
		LRET

EZRET	LRET