Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!apple!farrier
From: farrier@Apple.COM (Cary Farrier)
Newsgroups: comp.sys.apple
Subject: Re: Serial Port Status questions...
Message-ID: <38540@apple.Apple.COM>
Date: 12 Feb 90 03:14:07 GMT
References: <269@bucsb.UUCP>
Distribution: na
Organization: Apple Computer Inc, Cupertino, CA
Lines: 42

In article <269@bucsb.UUCP> ghost@bucsf.UUCP (Jay Adelson) writes:
>	I know how to read the 16-bit status register (or at least I'm reading 
>16 bits)  with the GS/OS DStatusGS call, but I don't know what any of the bits
>mean, except that an AND mask of $0020 checks if the receive register is full.
>Now, what I need to know is WHAT DO THE OTHER BITS REPRESENT?? Specifically,

The DStatus call ($202D), can take a few different inputs as to the type
of status request being made.  It sounds as if you are using the device
status code request (status_code = $0000).  The definition of the 16 bit
value returned by this call when made on a character device
is as follows:

	bit 15		Reserved
	bit 14		1 = Linked Device
	bit 13		1 = Device Background Busy (executing a background
							task)
	bits 12-6	Reserved
	Bit 5		Buffer not empty
	Bit 4		1 = Online, 0 = Offline
	Bits 3-2	Reserved
	Bit 1		1 = Device currently interrupting
	Bit 0		1 = Device currently open

>I need to know which bits represent ready to transmit, and carrier detect.
>I would like to know what all of them mean, though....

	For this type of information, take a look at the GetPortStat
	and GetDTR/SetDTR calls in the Apple IIGS Firmware Ref. Manual,
	on pages 104-105.

>	ghost@bucsf.bu.edu

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| Cary Farrier                          | Internet  : farrier@apple.com   |
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