[A83] Re: SE port 0A
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[A83] Re: SE port 0A
I posted this to the TI-H list some number of months ago, maybe it will help
you since you seem to be interested in the hardware. I've actually figured
out a good deal of information since then so some of this is out of date...
On the 83P, the following ports are used: 0,1,2,3,4,5,6,7,10h,11h,14h,16h
Functions:
0 - link port
1 - keyboard port
2 - hardware stuff (low battery indicator, etc).
3 - Power and interrupt enable
4 - Interrupt speed and type
5 - unknown
6 - memory bank0 page
7 - memory bank1 page
10h - LCD instruction port
11h - LCD data port
14h - Flash lock/unlock port
16h - unknown
....You may be wondering how I know these are the only used ports. Well,
TIOS outputs to all these ports, plus, all other ports seem to be "shadows"
of currently existing ports.
On the SE: All ports between 0-3Fh are either zero, or have some value.
Every port 40h-0FFh is set to 0FFh. Thus all usable ports must be in the
00-3Fh, though that's no guarantee that *all* ports in this range are used).
0 - link (direct line access)
1 - keyboard
2 - hardware version type, battery status, etc
3 - Power and interrupt enable
4 - Interrupt type and speed
5 - unknown (seem to behave different than 83P though)
6 - memory bank0
7 - memory bank1
8 - unknown (probably something to do with link port though)
9 - link port hardware assist status
Ah - link hardware assist input
Bh/Ch - unsure, but probably link hardware assist input buffer
Dh - link hardware assist output
Eh/Fh - unknown, initialized to zero by TIOS and never again used
10h - LCD instruction
11h - LCD data
12h - appears to be a shadow of 10h
13h - unknown, not used by TIOS at all
14h - Flash lock/unlock
15h - unknown, when read returns a value of 33h
16h/17h - unknown, not used by TIOS at all
18h-1Fh - seem to be a hardware interface to help with MD5 routines
20h - bit0 = select CPU speed, bit1 = unknown. Other bits not used
21h-26h - unknown, initialized to values by boot page, never used again.
Can't change values with an output to the port
27h-2Fh - unknown, have default values, values can be changed with no
noticeable effect, except port 29h, where if bit4 is reset, the calculator
crashes.
30h-37h - hardware timers
38h-3Fh - unknown, not used by TIOS at all.
-Dan Englender
----- Original Message -----
From: "Tijl Coosemans" <tijl@ulyssis.org>
To: <assembly-83@lists.ticalc.org>
Sent: Monday, February 11, 2002 12:03 PM
Subject: [A83] SE port 0A
>
> Does reading port 0Ah automatically reset the link assist or
> something, so it can receive a new byte? Or is this port overwritten
> when a new byte arrives?
>
> Anyone an idea about what ports 0B and 0Ch do? Extra buffers maybe?
>
>
References: