Re: TI-H: ti-calc schematics...
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Re: TI-H: ti-calc schematics...
>>Yes, you can control the TI link port by accessing port 7. However,
>>the TI calculators do not have an accurate timebase (they use an RC
>>pair rather than a crystal) so do not expect any kind of accurate
>>serial communication. Of course you could probably manage to do
>>RS-232 by having a loop measure the baud rate of an incoming CHR$(13)
>>-- I was just reading on article on how to do this on a C52 -- and
>>then you can send/rec stuff at that baud rate just knowing how long
>>to wait between bits. There is a pretty decent chance that the
>>8X won't be able to accurately or consistantly match that baud
>>rate though, it may be off a few percent. Over about 2.5% timing
>>error and you'll start to see errors. I recommend using something
>>like the graphlink if you really must have serial communication.
>>The E2 will also give you some extra interfacing options (4 I/O
>>and bi-dir half-duplex serial)
>
>Thats why I stated to get a DC to DC converter so the voltage stays the
>same. I think ALL ELECTRONICS had one for $3.
Umm, no Grant :).
Temperature can affect both the capacitance and resistance of a
circuit by as much as 25%. An accurate 6V source won't be of much
help. Plus, a DC-DC converter would introduce some very high
frequency ringing in the power supply and since we don't know how the
TI would react, it could even cause random crashes. Although most of
it could probably be removed with a low pass filter.
The only/best way to have RS232 is to have an external UART or crystal
controlled uC.
-Mel
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