Path: utzoo!attcan!uunet!microsoft!alonzo
From: alonzo@microsoft.UUCP (Alonzo Gariepy)
Newsgroups: comp.sys.handhelds
Subject: Re: HP28S PROCESSOR NOTES
Keywords: hp28s, cpu, processor, assembler, LED, correction
Message-ID: <9114@microsoft.UUCP>
Date: 21 Nov 89 16:21:50 GMT
References: <9085@microsoft.UUCP>
Reply-To: alonzo@microsoft.UUCP (Alonzo Gariepy)
Organization: Microsoft Corp., Redmond WA
Lines: 21

There are some minor corrections to these notes:

1.	The hex for the following two instructions was reversed.
	Here are the correct translations:

		09	MOVE.X 	ST,C			***
		0A	MOVE.X 	C,ST			***

	Make sure to fix this in both parts of the listing.

2.	SETHEX and SETDEC work just fine on the HP28 cpu.

3.	R4 is not used by interrupts and is available for program use.

I have learned that the use of the LED for a remote control is not feasible.  
The range of the LED is only a few feet compared to much more powerful LEDs 
in remotes.  The modulation frequency is wrong and would have to be simulated 
poorly.  There is a great danger of frying the LED.  I give up.

Alonzo Gariepy
alonzo@microsoft