TI-H: Complete SPinTerface FAQ (Right off my page)


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TI-H: Complete SPinTerface FAQ (Right off my page)



>Having a FAQ page around for the list is a good idea. Maybe I or 
someone
>else could put together a page based on what everyone here thinks 
should
>be in it and then we get ticalc.org or someone else to host it for all 
to
>see. Any ideas about this? If ti-calc.org could mention it right at the
>link to subscribe to this list it would help alot.

HERE IT IS...

The SPinTerface FAQ

______________________________________________________________________

                        The SPinTerface FAQs

What is the SPinTerface?
The SPinTerface is a "better" link port. It is NOT a brand new type of 
link port at all. It was
designed to not only let you link with the calc, but also the power 
supply. The SPinTerface has a
10-pin port that contains the three wires of the link, a ground and a 
5v+ supply, and a pair of pins to
ativate the regulated, 5v power supply for the port. It also allows you 
to dirrectly acces the batteries.
By connecting a cart to the lower activation pin and ground you can 
dirrectly acces the batteries.
This makes "jumper cables" and SPinTerface plug in power packs possible. 
The main advantage
however is the ability to dirrectly connect to both the link and a power 
source at the same time, with
no extra batteries, no extra power supplies, no extra regulators, and no 
expensive Link cables to cut
up and use. I can make 16+ cartridges out of the connectors in a Radio 
Shack male header pack for
$2.98! That's a lot better than spending $8+ to buy a link cable, cut it 
in two for two projects. Also,
the SPinTerface isn't too bad to build either. You need to have a steady 
hand and good soldering
skills, but you can easily do it for between $10 and $20, depending on 
where you get your parts.
The SPinTerface's primary design goal was to make cartridges easy to 
implement. Power, Serial
interface, Auto activation! It's all that's needed for a good cart. The 
second design goal for the
SPinTerface was to make prototyping easy. Why bother with a bench supply 
or extra cables in your
way when prototyping. I know two people who have crossed loose wires and 
blown a project or a
computer. A calc could just have easily been blown. The SPinTerface 
provides the 5v+ supply
incase you need it. You could even have a TI Power pack made to plug 
into the SPinTerface. It
would have a through port so carts could still plug in! I would connect 
a breadboard with atleast 6
busses to it. You can get the three link lines,and a Ground, 5v+, and 
unregulated battery supply.
You not only have testing easier, but you get realistic voltages, so you 
can see if the calc can run it!
The SPinTerface port is easy to use. It has a pin filled in the calc so 
you can't plug carts in the
wrong way! It automaticly powers up/down when you insert/remove a cart. 
This saves power when
you don't need a cart. It also eliminates the need for a $1-$3 switch to 
activate it and elliminates the
possibility of leaving the regulator run with no load. The cost idea is 
that if you pay for one power
supply, minus the cost of a battery case, you get a cheaper deal. You 
never have to build another
power supply again! You just impliment the SPinTerface activation pins, 
and draw power from the
5v+ line. If you need 3v or some special voltage, a small regulator 
connected between the activation
pins and ground will draw dirrect from the battery and not double 
regulate the power. You can still
draw the 5v+ if you still cross the activation pins and draw power from 
the 5v+ line and ground.
You just connect your cart's electronics to the link pins. Data is the 
red link wire (tip). Clock is the
white link wire (middle). Ground is the bare link wire (base). 

Why it's called the SPinTerface?
The original idea was an 8-pin port that had it's own batteries and a 
link cable. It was designed so
you could plug in Expander chips as cartridges. I called it the 
Serial/Powered Interface Port, or S/P
Interface. Later, when I completed the design and installed it, I put 
the whole thing together into
SPInterface, SPI for short. I read it as "Spin-ter-face," so I made the 
cases of some letters different
to emphasize the pronunciation (I was also into HyperCard at the time 
which has lots of handlers
written like that). The result is (drum roll please!!!) The SPinTerface. 

Why 10-pins and not 8?
Well, I simply didn't have luck finding any 8-pin headers. The smallest 
size was 10-pins. I'm sure
you could cut an 8-pin header, or find one somewhere, but why complain! 
If you want an 8-pin
header, you're just going to make more work for yourself. You would 
either have to look and look
and then special order it, or you would have to cut it and glue the 
back, since it won't stay if the side
tabs get cut off. I used 10-pin header because it's more convenient! 

How do you interface with the SPinTerface?
The SPinterface can be linked to the calc the same way as the link port 
is. There is absolutely no
difference in software or hardware, except the connectors. If you want 
to write software for the
SPinTerface and the link port, write it for the link port. There is no 
special routines or programming
required to use the SPinTerface. All it changes are the connectors and 
adds a power supply. 

Does the link port still work with the SPinTerface?
Yes, the link port still works. Many carts though will interfere with 
normal link port opperations.
Most carts should be removed when you want to use standard TI protocol 
linking that doesn't
require the cart to be present. Sometimes, if you want to daisy chain 
the link port so two calcs can,
say, read data from a temperature cart, you can link the two calcs 
together and have the Temp cart in
another, even if that calc is off, you'll still be able to read the temp 
cart through the link port. 

What is needed to build the SPinTerface?
Well, the parts list varies. here it is though, in it's simplest form:

One .1uf ceramic disk capacitor. (avaliable at Radio Shack)
One 10uf electrolytic capacitor. (avaliable at Radio Shack)
One 10-pin female header (see note 1)
One Low Dropout, Low Power, 5v+ voltage Regulator. (see note 2)

Note 1: Many electronics stores have them. Radio Shack has a 34-pin 
header
that can be cut into three individual 10-pin female connectors.
If you like, you can check DigiKey (1-800-344-4539) or Mouser 
(1-800-346-6873)
Note 2: The regulator used by the SPinTerface needs to be a low dropout 
regulator.
National Semiconductor makes several regulators that are excelent for 
this purpose.
You can purchase them through DigiKey, or, if you're cheap like me (; 
you can go
to National's Website. search for the low dropout regulators and go to 
the bottom
of the data page. There will be samples of many parts, and the 
regulators are some of them.
Register yourself and order the parts you need. You can order only once 
for each part,
but you can order up to five at a time. You can't order any more than 5 
parts per week though.
The parts you need to look for are:

One LM2931Z-5.0
or
One LP2954IS

Personaly, I would recomend the LM2931, but if you can't get it, the 
LP2954 should be fine too.
Idiot me forgot I had National's Power ICs databook. I had all this info 
and never looked at it once! 

Why install one?
It's a matter of need or want. I can't say that you need it. You get it 
installed because you want one.
If you hate carying that expander with a 6 inch wire hanging out of it, 
and you'd rather have a tiny
cartridge, then it would brobably be best to have a SPinTerface 
installed and have the expander
turned into a cartridge. Why install it? For convenience. If you wan't 
to be able to plug your calc
into a power pack, it ought to be simple with the SPinTeface. If you 
want to build lots of link
projects, but don't want to spend $4 on each just for an $8 link you 
have to cut in half, or you hate
building so many separate ower supplies and buying so many batteries, 
then the SPinTerface is for
you. If you like prototyping, it also becomes a useful tool. It's up to 
you whether you need it
though. 

What if you want a SPinTerface, but are scared to mess with your calc?
Easy! build an external SPinTerface. You still only need to build one 
power supply and use only
one cable and buy only one set of batteries. All you need to do is get a 
case that will hold 4
AA/AAAs or a 9 volt (AAs are best though). Put the electronics into it, 
connecting the link cable
where you would connect to the link jack and the battery terminals to 
the batterys. It's easyier and
safer to build an external one, even though the way the SPinTerface is 
designed, it is actualy very
safe to install. 

What calcs can it be installed on?
Any calc with a link port. That includes the TI-82, 83, 85, 86, and 92. 
The TI-85 is probably the
one that would get the most use from the SPinTerface. The TI-92 is a 
CLOSE second, and then the
others have some stuff that will work, but not much. They would probably 
only use a speaker cart
and the power pack until people start doing a lot more programming on 
them. There are some
expanders that should work with most of the calcs. When they are 
finnished, anyone will have a
good reason to install a SPinTerface port into their calc. 

SPinTerface "Jumper" cables and Power cables?
Both of these are relativly simple ideas. The jumper cable would have 
two SPinTerface cartridge
connectors at each end, possibly a female cart in the middle. This would 
let two calcs link to the
same device, like an I2C temp sensor (I tried it, It works!). You can 
also link the calcs together, just
like the standard link port, but it doesn't just link the serial port, 
it links the power supplies too. You
may wonder why that's important, but have you ever tried to link with a 
calc with realy low
batteries, maybe to copy their stuff so they don't lose it. It sometimes 
doesn't want to link because
there isn't enough power to do it. The SPinTerface jumper cable would 
link the batteries in paralel,
sharing power equaly between the two, so both have nearly identical 
power levels and can send
with fewer errors. The SPinTerface power pack would be a 4.5-6v power 
pack with a low current (150 ma to be exact)
power source. It would have a male and a female connector joined in line 
so you plug it into the calc
and carts into it. The + would connect to the lower activation pin 
(which connects to the battery) and
the - to the ground. It could power any TI-8x/92 with a SPinTerface port 
installed. Imagine that! 

What are those Virtual Boy gamepack covers for?
The Virtual Boy gamepack covers are small plastic dust covers for the 
Virtual Boy games. If you cut
them in half, right down the center, and glue the long ends together, 
you have a nice looking
cartridge case for small SPinTerface projects. I use them for sound 
carts and Expander carts
especialy. They will hold the SF Expander's PLCC chip easily. Solder on 
the side of the chip, point to point, and you have a small expander cart 
that is
1.5" long x 1" wide x 1/4" thick. They have nice beveled edges that make 
them look like they came
from a high quality manufacturer. The only distracting nature is the 
seam in the center, where the
two cart cover pieces join, but even that, if done right can look almost 
perfect! Nintendo gives them
for FREE!!! Just call them () and request as many as you need. Tell them 
you bought a used Virtual
Boy and you want covers for all the gamepacks!!!  =P  q= 

Why don't some PLCC chips fit, you said they would?
The reason some PLCC chips don't fit is because they have a J shaped
lead. That curved part of the J sticks down a bit, jut far enough to 
make some of the chips not fit. If you take
a pair of pliers and flatten the bottom of the leads, and you solder on 
the sides of the chip, it will fit
tightly, but comfortably!
NOTE: This is not true for all PLCC chips, it depends on the die run. 
Some are thicker and some fit just nicely. The PLCC used by National to 
make the NM29A040/080 chips should fit nicely.

Many people want GameBoy games, why isn't it happening?
GameBoys use a Z80 processor. Why can't you port a GameBoy game to a TI? 
there are several
reasons. First, the ROM chips in the two devices are different. You 
would need to dump the whole
ROM, find similar commands and routines and make Z-Shell or library 
based routines to cover the
ones not included (that alone would require an expander). Next, the 
GameBoy has 64K of memory.
It loads large chunks of software, which the TI's (86 excluded) don't 
have. You would also need to
redo the graphics and sound routines from scratch. The processor, I'm 
told, is also a bit different.
All these differences make GameBoy carts on a TI-85 nearly impossible. 
The closest possible
candidate for GameBoy software would be the 86, since it has so much 
memory. You still would
need to solve those other problems. It would be easiest to work from 
scratch, or at least try to learn
from the game's code, and that would also be extremely difficult. 

What about single program or one write carts?
It would be possible to use serial EPROMS or Flash memory with no write 
functions enabled to
create carts with permanent software on them. You could load the 
software manualy or even have it
test to see if a device is connected and start auto loading if it is a 1 
program cart. The software is the
main thing. The OS would need to support it. At least a driver for it. 
It wouldn't be that difficult to
create program carts. If you used I2C or a microcontroler, you could 
even probably have the
permanent program on EPROM with a Flash chip to store data files or 
preferences. 

The SF Expander cart?
The SF Expander cart is a cartridge that uses the old SF Expander chips 
(NM29A040/080) to add
512K or a Megabyte of storage memory. The instructions for building it 
are on the SPinTerface
Cartridge page, as are instructions for all other completed SPinTerface 
Accessories. The SF
Expander uses Serial flach memory. One question that is common is "Is it 
true that you can ruin the
chip if you use it too much?" The answer is that if you write, or copy 
things to the chip over and
over, then yes, the chip will fail. Reading the chip doesn't hurt it. 
You can erase a program from
your calculator and copy it back to the calc, from the Expander cart as 
many times as you like. Put
short, Send files to the expander only once or twice. If you need to 
delete something and put
something in its place, that's OK. Just don't save your game to the 
expander every time you get a
high score. That will ruin it. You can get data and read data from it as 
much as you like though.
Don't worry. It should be able to handle over 100 writes to the same 
area of memory. this doesn't
mean you can only write 100 things to it. It means that each of the 256 
sections of the expander's
memory can only be written to a limited number of times. The expander 
can hold between 210 and
240 individual files, depending on the chip's quality of manufacturing 
or it gets lower if you write
to it too much and a section fails. Each section is 2048K or 4096K (512K 
chip & 1 Meg chip). Each
section can only hold one file, but a file can consist of one or several 
sections. The expander works
a lot like a hard drive. It's just a chip instead though! (= 

The Speaker cart?
The speaker cart is a small cart with a speaker, transistor, and a 
variable resistor to change the
volume. The transistor is connected to the power supply and the link 
port. It takes the 1-bit sound
data from programs like Z-Pong, Playwav, and sound, amplifies them using 
the powered transistor,
and sends them through the volume control and speaker to create the 
sound. If you use a voltage
regulator that puts out too much power, it will draw power from the 
batteries and away from the
calc. The screen will dim and the sound will bee so loud that playwav 
can't be made out. A lower
power regulator should aleviate this problem, however it isn't tested 
yet. I'm also looking into the
idea of using Piezo electric disks as speakers. They may not be as loud, 
but I think that it might
make it to where it won't crash the calc when you're not in Z-Shell. I'm 
also going to try using
diodes to get the thing to allow linking, even when it's plugged in. 
I'll release any new designs on
the SPinTerface Cartridge Page. 

The Temp cart?
The I2C Temperature Sensor cart has several important issues to clear 
up. The original text for the
Link Port based I2C temp sensor said the chip updates 2x per second. 
That doesn't mean that if
there is a sudden drop in temperature, that it will register it 
immediately. People have said "it took 5
Minutes to get below 32 degrees F in a freezer. This thing isn't 
accurate!" Actualy, you can't get
much better than that! Heat takes time to condut itself in or out of an 
object! That's why you need to
hold a digital thermometer in your mouth for about a minute. That's why 
the pot takes several
minutes n a red hot stove before it actualy reaches a high temp. That's 
why you can't throw a 1
pound pork roast into a frezer and it doesn't freeze instantly. Even if 
you add a metal probe to pin 4
(which is the sensor pin), it still isn't going to be instant. The 
original application of the chip was to
detect atmospheric temps. Atmospheric temps change gradualy. People are 
trying to test surface
temps and they think the thing doesn't work right becauseit's too slow. 
This is NORMAL!!! It can't
be fixed unless you teach me how to change the laws of physics. I am 
looking into new chips with
faster response times and greater ranges. Hopefully they are compatible! 

The Light Flasher Cart?
The TI-85 light flasher was designed as a device to allow the TI-85 to 
run flashing light sequences
for DJs and partys. The circuit comes in two versions. One version is 
easier to find the parts, but
doesn't hold the lights on for the full cycle. The other keeps the 
lights on or off till they are changed
by the calc. I have not built it for the SPinTerface port yet, but it is 
an easy task. The design can also
be modified to act as an 8-bit output generator to control parralel 
devices. The device could also be
reworked using the I2C 8-bit interface chip, but it would require new 
software. The advantage
though would be that it could be connected to an ADC to convert the 
analog sound signal to digital.
Software could possibly be made to flash lights to beats in the music! 

Extender uP and Expander II/III carts?
I will be doing cartridge conversions later on when those devices are 
released. I may Even produce
them in cart form with parts dirrectly ordered from the creators. The 
Extender uP is a small device
and I believe that a large cart could be made for it. I believe that the 
Extender uP and the Expander
III will have RS232 ports to interface with devices. The Expander II is 
a basic expander for the
people who don't need anything special. The Expander III however is 
claimed to be the planned
"All out" device with the Serial port, through link port, possible 8-bit 
sound, and more! No
guarantees though, they haven't been released yet. 

The clock cart?
Many people have brought up the idea of a realtime clock on the TI-85. I 
may be designing one if
there isn't one already. I believe that one was designed, or at least 
planned, but was possibly never
finnished. if I get any news on it, or make a prototype, I'll anounce 
it. I will need people to do the
software for me though. 

The 8-bit Sound Cart?
I have come up with a possible design for an 8-bit sound cartridge. It 
works by using a DAC to
convert a stream of serial data from digital to analog to drive a 
speaker. I'm going to see if the
reference can be used to adjust the volume control. The MAX549 would be 
capable of stereo 8-bit
sound, but I think that would take too much data transmission power to 
run. The MAX550B is a
single DAC chip. It is the ideal chip for mono 8-bit sound. Both chips 
can accept data at up to
10MHz, so you can send data at the highest rate you can get it at 
because the link port doesn't even
get close to that. I personaly would use sine, triangle, square, or 
noise functions to generate most
sounds because digitized 8-bit takes 5K per second to get a 5KHz audio 
sample. That's a lot of
memory! If you want digitized sound, you could do it, but function based 
sound takes less
memory. You could even do the and or xor stuff to do multiple chanels. 
Imagine a type of TI MIDI!
I will need software written for the 8-bit sound generator, and if it 
works, we could even emulate
GameBoy Sound, since the GameBoy uses a function generator to create 
sound! 

IR Links, Why are we getting no where?
IR links are very precise devices. They can't just send out raw data. 
They need a carier wave to
allow the data to "ride" it. You need extremely tight timing to do this, 
and the TI calculator's serial
port just doesn't cut it! The serial port in a TI uses RC (or Resitor 
Capacitor) networks to create the
clock. The temperature, humidity, battery level, everything affects its 
speed and accuracy. A crystal
oscilator would have given it the accuracy to work, but crystals break 
easily, and TI knows how we
all love to drop our calcs!!! What would you rather have, a cheap IR 
link that's easy to build and a
calc that could quit working if you dropped it once, or a complex IR 
Link and a calc that is sturdy
and long lifed? 

Radio Links, what's taking so long to make one?
The radio link is a lot like the IR problem. It requires a carier 
signal, but with an RF link, the Radio
Interference messes up the transmission! It is extremely dificult to 
make a Radio link work. It's a
dificult task. 

The TI Modem. Is it possible?
Several people have tried to made a modem, but to make a modem, you need 
to
MOulate/DEModulate the signal. That means that you need to modulate a 
tone as a carier signal
(sound familiar) and the data is riden on it. To demodulate, the modem 
needs to filter the data from
the carier tone. This is difficult and took years to develope. The best 
way to go is to use a cheap
surplus modem and an RS232 interface, like the graphlink cable or an 
Extender/Expander when
they are finnished.


I wish all hardware and software hackers luck in their projects to 
improve the TI calculators. (; 

______________________________________________________________________


Richard Piotter

e-mail: richfiles@hotmail.com

home page: <A 
HREF="http://www.geocities.com/SiliconValley/Lakes/5081/Richfiles.html">The 
Richfiles</A>
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