83Plus:Ports:03 - Revision history

Dr. D'nar at 06:26, 11 September 2013

2013-09-11T06:26:21Z

Jim e: spelling

2007-05-19T18:01:47Z

spelling

AndyJ: it's -> its possesive, link to wikipedia as interwiki link

2007-05-19T16:55:04Z

it's -> its possesive, link to wikipedia as interwiki link

Jim e: Just noticed I loaded i with the wrong value

2007-05-19T08:59:56Z

Just noticed I loaded i with the wrong value

Jim e: Another example, bit more detail in ACKs, removed link to my site since its old and deprecated.

2007-05-18T21:39:52Z

Another example, bit more detail in ACKs, removed link to my site since its old and deprecated.

Saibot84: added bit about needing to clear ints

2006-09-02T07:09:48Z

added bit about needing to clear ints

Kalimero: write bit 3

2005-04-09T08:58:00Z

write bit 3

FloppusMaximus at 05:17, 30 March 2005

2005-03-30T05:17:08Z

JasonM at 22:41, 29 March 2005

2005-03-29T22:41:19Z

Kalimero: /* Write Values */

2005-03-28T22:42:33Z

‎Write Values

← Older revision		Revision as of 06:26, 11 September 2013
Line 4:		Line 4:

	'''Function:''' Interrupt Masking Port		'''Function:''' Interrupt Masking Port
		+
		+	''See also: [[83Plus:Interrupts]]''

	This port controls what devices will be allowed to trigger interrupts. When an interrupt is triggered, it should be cleared by reseting the corresponding bit. Otherwise, it will continuously call the interrupt code once interrupts are reenabled with ei.		This port controls what devices will be allowed to trigger interrupts. When an interrupt is triggered, it should be cleared by reseting the corresponding bit. Otherwise, it will continuously call the interrupt code once interrupts are reenabled with ei.

@@ Line 45: / Line 45: @@
   <nowiki>Install_ISR:
-;Disableing interrupts prior to installation.
+;Disabling interrupts prior to installation.
 ;This is in case an im 2 interrupt is already running.
 ;(MirageOS would present such a case.)
@@ Line 60: / Line 60: @@
 	ld (hl),$8A
 	ld de,$8B01
-	ld bc,257
+	ld bc,256
 	ldir
@@ Line 71: / Line 71: @@
 ;would be required to use that area.
+;
-	ld hl,Interupt_Start
+	ld hl,Interrupt_Start
 	ld de,$8A8A
-	ld bc,Interupt_End-Interupt_Start
+	ld bc,Interrupt_End-Interrupt_Start
 	ldir
@@ Line 108: / Line 108: @@
-Interupt_Start:
+Interrupt_Start:
 	exx
 	ex af,af'
@@ Line 140: / Line 140: @@
 	ei
 	ret
-Interupt_End:</nowiki>
+Interrupt_End:</nowiki>

@@ Line 27: / Line 27: @@
 ===Soft Powerdown===
 This example shows how to do a soft powerdown (similar to the auto powerdown) on the calculator.
-This may or may not wipe the LCD screen, so you should first copy it's contents to a buffer like saveSScreen and then copy it back afterwards.
+This may or may not wipe the LCD screen, so you should first copy its contents to a buffer like saveSScreen and then copy it back afterwards.
   <nowiki> push af
   ld a, 11h ;Enable linkport, ON key. Disable timer.
@@ Line 42: / Line 42: @@
 ===Simple Interrupt===
-This example will show how to set up the first timer for an interrupt and its use in the [http://en.wikipedia.org/wiki/Interrupt_handler ISR].  It will also show beyond just port 3 usage since this port requires more complex interaction for its typical use.
+This example will show how to set up the first timer for an interrupt and its use in the [[wikipedia:Interrupt_handler|ISR]].  It will also show beyond just port 3 usage since this port requires more complex interaction for its typical use.
   <nowiki>Install_ISR:

@@ Line 91: / Line 91: @@
 ;should be considered random.
+;
-	ld a,$8A
+	ld a,$8B
 	ld i,a
 	im 2

@@ Line 5: / Line 5: @@
 '''Function:''' Interrupt Masking Port
-This port controls what devices will be allowed to trigger interrupts. When an interrupt is triggered, it should be cleared by reseting the corresponding bit.  Otherwise, it will continously call the interrupt code once interrupts are reenabled with ei.
+This port controls what devices will be allowed to trigger interrupts. When an interrupt is triggered, it should be cleared by reseting the corresponding bit.  Otherwise, it will continuously call the interrupt code once interrupts are reenabled with ei.
 === Read Values ===
@@ Line 14: / Line 14: @@
 === Write Values ===
-* Bit 0: Set 1 to enable the ON key. Set 0 to disable it.
+* Bit 0: Set 1 to enable the ON key. Set 0 acknowledge the interrupt request and/or to disable it.
-* Bit 1: Set 1 to enable the first hardware timer. Set 0 to disable it.
+* Bit 1: Set 1 to enable the first hardware timer. Set 0 acknowledge the interrupt request and/or to disable it.
-* Bit 2: Set 1 to enable the second hardware timer. Set 0 to disable it.
+* Bit 2: Set 1 to enable the second hardware timer. Set 0 acknowledge the interrupt request and/or to disable it.
 * Bit 3: Set 0 to put the calculator in low power mode if and only if the Z80 cpu enters the halt state (during the executing of a halt instruction). Set 1 to keep the calculator powered.
-* Bit 4: Set 1 to enable the linkport interrupt. Set 0 to disable it. (Does not completely disable the linkport.)
+* Bit 4: Set 1 to enable the linkport interrupt. Set 0 acknowledge the interrupt request and/or to disable it. (Does not completely disable the linkport.)
 == Comments ==
-* For normal operation, write 0B (00001011) to this port.
+* For normal operation, write 0B (00001011) to this port. This will allow the first timer to generate interrupts, and the on key.
 * In low power mode it is known that at least the lcd driver enters standby mode and that the timer hardware has been disabled.
 == Example ==
 This example shows how to do a soft powerdown (similar to the auto powerdown) on the calculator.
 This may or may not wipe the LCD screen, so you should first copy it's contents to a buffer like saveSScreen and then copy it back afterwards.
@@ Line 39: / Line 40: @@
   out (3), a
   pop af</nowiki>
 == Credits and Contributions ==
 *'''Michael Vincent''': For documenting [http://www.michaelv.org/programs/calcs/ports/port3.html here] on the interrupt bits.
-*'''James Montelongo''': For documenting [http://www.geocities.com/jimm09876/calc/port3.html here] on the interrupt bits.
+*'''James Montelongo''': For documenting the interrupt bits.

@@ Line 1: / Line 1: @@
-[[Category:83Plus:Ports:By_Address|03 - Interrupt Mask]]
+[[Category:83Plus:Ports:By_Address|03 - Interrupt Mask]] [[Category:83Plus:Ports:By_Name|Interrupt Mask]]
 [[Category:83Plus:Ports:By_Name|Interrupt Mask]]
 == Synopsis ==
 '''Port Number:''' 03h