Subject:
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Re: How to get digital outputs from the handyboard?????????????
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Fri, 11 Dec 1998 18:00:23 GMT
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Original-From:
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Will <willbain@cs.umtSTOPSPAM.edu>
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Reply-To:
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willbain@cs.umt.edu&NoMoreSpam&
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Viewed:
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1286 times
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Michael Toh wrote:
> hi everyone, i have been trying for the past few days to get digital outputs
> from the board but with no success. i have been trying to get digitals
> outputs from the SPI's pins (J6). i have poke to make the port as output
> port. but the problem now is how to config the 4 bits. what is the location
> and the mask bit to do a bit_set/clear.
First, to enable the four SPI pins D2 through D5 as digital outputs,
make sure you do a bit_set( 0x1009, 0x3C ). (In the sonar.c program,
for example, bit_set( 0x1009, 0x30 ) seems to only enable two of the
pins--not all four). I think poke would work OK here, too, even though
it actually clears bits in addition to setting bits.
The middle 4 bits of byte 0x1008 map to ports D2 through D5. To send
the pins high, do the following:
Bit mask
Port Send high 7654 3210
--------- ----------------------- ---- ----
D2 (MISO) bit_set( 0x1008, 0x04 ) 0000 0100
D3 (MOSI) bit_set( 0x1008, 0x08 ) 0000 1000
D4 (SCK) bit_set( 0x1008, 0x10 ) 0001 0000
D5 (SS) bit_set( 0x1008, 0x20 ) 0010 0000
Of course, to send 'em low again, just do the corresponding bit_clear.
You can set or clear multiple bits in one statement; you just need to
figure out what the bit mask equates to in hexadecimal. You could even
set *and* clear bits simultaneously by using poke (instead of bit_set or
bit_clear) with the appropriate mask. Good luck!
-- Will
, ,
__@_/ \_@__ |/
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)\ ) ( \ (\/\\,
~~~~~~~~~ ' ` ~~~~~~~~~~~ ` ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Wendy Parson, I can't take a
Will Bain, well-tanned person seriously.
& Tatoosh --Cleveland Amory
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