Added Address Bus verification

Verify Address Bus functionality prior to starting individual RAM memory location test

Source/Apps/ramtest/dbgmon.asm

@@ -936,6 +936,45 @@ DATABUSFAIL:
 	CALL	MSG			; DISPLAY IT
 	JP	SERIALCMDLOOP		; AND BACK TO COMMAND LOOP
 
+; VERIFY ADDRESS BUS FUNCTIONALITY BEFORE STARTING MEMORY TEST
+	LD	A,$80			; FIRST 32KB PAGE ONLY
+	LD	(PAGE_NUM),A		; STORE WORKING PAGE NUMBER
+	OUT	(MPCL_ROM),A		; SWITCH OUT LOWER 32KB ROM PAGE
+	OUT	(MPCL_RAM),A		; SWITCH IN LOWER 32KB RAM PAGE
+	LD	A,$00			; INITIALIZE A TO 0
+	LD	($0000),A		; WRITE TO LOWEST RAM ADDRESS
+	LD	HL,$0001		; INITIALIZE HL TO CHECK A0
+	
+ADDRBUSCHECK:
+	LD	(HL),$FF		; WRITE ALL ONES INTO HL ADDRESS
+	LD	C,($0000)		; READ VALUE FROM LOWEST RAM ADDRESS
+	CP	C			; IS IT SAME AS WRITTEN?  SHOULD BE 0
+	JP	NZ,ADDRBUSFAIL		; NO? ADDR BUS FAIL HANDLER ROUTINE
+	PUSH	HL			; STORE HL, FOR COPY TO BC
+	POP	BC			; RETRIEVE BC (SAME AS HL)
+	ADD	HL,BC			; INCREMENT TO NEXT ADDR LINE
+	LD	A,H			; WHICH ADDRESS LINE ARE WE AT
+	CP	$80			; ARE WE AT A15?
+	JP	NZ,ADDRBUSCHECK		; NO? REPEAT FOR ALL 15 VALUES
+	LD	HL,TXT_ADDR_BUS_PASS	; YES? POINT AT ADDR BUS PASS TEXT
+	CALL	MSG			; PRINT ADDR BUS PASS LABEL
+	JP	MEMSIZELOOP		; CONTINUE WITH REST OF RAM TEST	
+	
+ADDRBUSFAIL:
+	PUSH	HL			; STORE FAILED ADDR LINE VALUE	
+	LD	HL,TXT_ADDR_BUS_FAIL	; POINT AT ADDR BUS FAIL TEXT
+	CALL	MSG			; PRINT ADDR BUS FAIL LABEL
+	POP	HL			; RETRIEVE FAILED ADDR LINE VALUE
+	LD	A,H			; PRINT UPPER HALF OF ADDRESS
+	PUSH	HL			; STORE FAILED ADDR LINE VALUE
+	CALL	HXOUT			; PRINT HIGH ADDR HALF THAT FAILED
+	POP	LH			; RETRIEVE FAILED ADDR LINE VALUE
+	LD	A,L			; PRINT LOWER HALF OF ADDRESS
+	CALL	HXOUT			; PRINT LOW ADDR HALF THAT FAILED
+	LD	HL,TCRLF		; CR & LF
+	CALL	MSG			; DISPLAY IT
+	JP	SERIALCMDLOOP		; AND BACK TO COMMAND LOOP
+
 MEMSIZELOOP:
 	LD	HL,TXT_RAM_TEST_MAIN	; POINT AT RAM TEST MAIN MENU TEXT
 	CALL	MSG			; PRINT MENU TEXT LABEL
@@ -1177,6 +1216,16 @@ TXT_DATA_BUS_PASS:
 	.DB   "DATA BUS PASS "
 	.DB   CR,LF,ENDT
 
+TXT_ADDR_BUS_FAIL:
+	.DB   CR,LF
+	.DB   "ADDR BUS FAIL, VALUE ="
+	.DB   ENDT
+
+TXT_ADDR_BUS_PASS:
+	.DB   CR,LF
+	.DB   "ADDR BUS PASS "
+	.DB   CR,LF,ENDT
+
 TXT_SKIP_16:
 	.DB   CR,LF
 	.DB   "SKIPPING PAGE 0F "