Subject:
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lcd page zero driver and interrupts
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Mon, 17 Sep 2001 11:58:35 GMT
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Viewed:
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2163 times
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I am prototyping an interrupt driven system on the Handy Board in assembly
language. I want to use the onboard LCD and have implemented a page zero
driver as described beginning on page 356 of Robotic Explorations, by Fred
Martin.
The LCD driver works okay on its own but appears to interfere with operation
of hardware interrupts. I tried disabling all interrupts around the call to
the page zero lcdwrite routine but that doesn't help.
My guess is that switching the 6811 from expanded mode to single chip mode
and back to expanded mode, as the page zero lcd driver does for every byte
output, whacks the flow of the interrupt system.
The interrupt drivers I am using include a beeper driver(that counts down a
duration) and a real-time clock driver. I have a simple test program that
beeps every second driving the beeper and the clock from interrupts. This
works perfectly unless I include calls to the lcd driver. The lcd driver
works perfectly on it's own without interrupts activiated.
Does anyone know for a fact that there is a dilemma with the page zero lcd
driver approach and interrupts?
Does anyone know another way to interface with the Handy Board onboard lcd?
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Message has 1 Reply:
 | | Re: lcd page zero driver and interrupts
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| This will probably bounce to the Handyboard list but here goes ... (...) The way the default LCD program is written is non-optimal. This is because the LCD is a fairly slow device relative to the 68HC11. The default LCD code spin locks on the (...) (23 years ago, 18-Sep-01, to lugnet.robotics.handyboard)
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