On Flag? Huh?

Post by **L4E_WakaMol-King** » Sun 07 May, 2006 7:22 am

I was reading around on the Learn ASM in 28 days thing, and found an On Flag (OnRunning). It it set to 1 if the calculator is on. Why in the world would you need that? It's not like you can write code to execute when the calc is off...

Post by **Dwedit** » Sun 07 May, 2006 7:44 am

When you replace batteries, it might be nice to know what state the calc was in previously when the Z80 resets...

Spencer · Post by **Spencer** » Sun 07 May, 2006 6:23 pm

Well, the flag would be reset if the batteries are removed. It's likely for benefit of interrupt events that can occur when the calc is off. Link port, on key. Then again, I know nothing of TI-OS ...

Post by **L4E_WakaMol-King** » Sun 07 May, 2006 7:12 pm

Hmm, perhaps. But even in these cases mentioned, it would have to be 0 at some times... and it doesn't seem to make much sense for the calc to check if it is on.

If it's being used for something like battery replacement or link port stuff, then it would have to remain as 0 even a little after being turned on. Then the calc could check if it is on and find that, in fact, it is off. Talk about an identity crisis...

threefingeredguy · Post by **threefingeredguy** » Sun 07 May, 2006 9:16 pm

The calculator is still running when it is off, it is just halted and waiting for an interrupt. So I guess if the on flag is not set, then power down and wait for this interrupt.

Liazon · Post by **Liazon** » Sun 07 May, 2006 10:48 pm

isn't the calc still consuming power when it's off?

threefingeredguy · Post by **threefingeredguy** » Sun 07 May, 2006 11:01 pm

Yes, but very little.

NanoWar · Post by **NanoWar** » Mon 08 May, 2006 3:47 pm

You can send a file while the calc is off. Wow, that's useful..

Post by **benryves** » Mon 08 May, 2006 4:11 pm

The calculator switches itself on when you do anything on the link port (there are a number of different things that can fire interrupts - timers (disabled when the calc is off), on key, and link port).
I believe the on flag is just to save the state of the calculator - if it handles an on-key interrupt, it then checks the flag. If the calculator is off, it switches on. Otherwise, it checks for the 2nd key flag (and if that's set it switches off). Then it toggles the flag.

Timendus · Post by **Timendus** » Mon 08 May, 2006 4:13 pm

benryves wrote:The calculator switches itself on when you do anything on the link port (there are a number of different things that can fire interrupts - timers (disabled when the calc is off), on key, and link port).

Unfortunately Ti-83s don't have the link interrupt, or so I've been told... I'll try never the less of course

I believe the on flag is just to save the state of the calculator - if it handles an on-key interrupt, it then checks the flag. If the calculator is off, it switches on. Otherwise, it checks for the 2nd key flag (and if that's set it switches off). Then it toggles the flag.

Sounds very likely

threefingeredguy · Post by **threefingeredguy** » Tue 09 May, 2006 1:15 am

The link interrupt comes with silent linking, right?

Post by **Dwedit** » Tue 09 May, 2006 3:48 am

I thought the link interrupt was when you plugged in the link cable, and it turned on the calc.

threefingeredguy · Post by **threefingeredguy** » Tue 09 May, 2006 4:04 am

I don't know, I was asking.

Kalimero · Post by **Kalimero** » Tue 09 May, 2006 8:44 am

bit 4: link port interrupt line, 1 means interrupt requested
An interrupt is requested when both lines were high and one or both go low, either when this calc or the other end drives a line low or because while plugging in a cable, one of the lines is briefly connected to ground.