Need help with LED Terminal AppMod
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Posts: 46,084
Ron-
Noninverted it is (logical 1 = idle line = stop bit = high; logical
0 = start bit = low). The other thing to recognize is that the $8000
tells you the AppMod serial I/O is open drain (driven low, pulled
high), so your PIC can drive the line low to represent a zero, and
set the pin to input and allow the line to be pulled high to
represent a one, and thereby share access to the AppMod's serial
line.
Steve
On 30 Jan 01 at 22:07, Ron Hackett wrote:
> I just started working with the LED Terminal AppMod from Parallax,
> and something has me confused. Their programming examples all use
> "32+$8000" as the baudrate parameter for the serout commands. If I
> have this right, it signifies a baud rate of 19200, 8 bits, no
> parity and non-inverted. What confuses me is that the LED terminal
> does not appear to have a level-shifting RS-232 chip on it, so I
> would have espected the terminal to require inverted input, not
> non-inverted.
>
> Since I plan to use the terminal with a PIC16F84, I need to be sure
> which is correct for serial output to the LED terminal (inverted or
> non-inverted).
>
> Thanks for any clarification you can provide.
>
> Ron
> _________________________________________________________________
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>
>
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Noninverted it is (logical 1 = idle line = stop bit = high; logical
0 = start bit = low). The other thing to recognize is that the $8000
tells you the AppMod serial I/O is open drain (driven low, pulled
high), so your PIC can drive the line low to represent a zero, and
set the pin to input and allow the line to be pulled high to
represent a one, and thereby share access to the AppMod's serial
line.
Steve
On 30 Jan 01 at 22:07, Ron Hackett wrote:
> I just started working with the LED Terminal AppMod from Parallax,
> and something has me confused. Their programming examples all use
> "32+$8000" as the baudrate parameter for the serout commands. If I
> have this right, it signifies a baud rate of 19200, 8 bits, no
> parity and non-inverted. What confuses me is that the LED terminal
> does not appear to have a level-shifting RS-232 chip on it, so I
> would have espected the terminal to require inverted input, not
> non-inverted.
>
> Since I plan to use the terminal with a PIC16F84, I need to be sure
> which is correct for serial output to the LED terminal (inverted or
> non-inverted).
>
> Thanks for any clarification you can provide.
>
> Ron
> _________________________________________________________________
> Get your FREE download of MSN Explorer at http://explorer.msn.com
>
>
>
>
>
Comments
something has me confused. Their programming examples all use "32+$8000" as
the baudrate parameter for the serout commands. If I have this right, it
signifies a baud rate of 19200, 8 bits, no parity and non-inverted. What
confuses me is that the LED terminal does not appear to have a
level-shifting RS-232 chip on it, so I would have espected the terminal to
require inverted input, not non-inverted.
Since I plan to use the terminal with a PIC16F84, I need to be sure which is
correct for serial output to the LED terminal (inverted or non-inverted).
Thanks for any clarification you can provide.
Ron
_________________________________________________________________
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