Re: Do you bother with reading from the LCD (HD44780)?

Hi Spehro,

"Spehro Pefhany" <speffSNIP@xxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:patjq3582hd9beabp1g5dspojog27bu7uf@xxxxxxxxxx
You don't need to spin in an idle loop you know, there are lots better
ways to handle things if it's desirable (interrupts, polling loop with
timer etc.)

Indeed, although unfortunately LCDs fall into that category where interrupts
don't really look all that attractive because the "typical" LCD write time is
often around 1us per character. For your "run of the mill" "some MHz"
microcontroller, making such an interface interrupt driven may actually end up
slower than polling!

Sometimes you might want it to limp along even if the display failed.

Agreed, in some systems that would be preferable

---Joel


.

Relevant Pages

  • Re: [REGRESSION 2.6.28-rc2-git3] lots of extra timer interrupts costing 2W
    ... powertop is reporting a huge number of excess timer interrupts on my ... It's commit fb02fbc1, "NOHZ: ... # CPUFreq processor drivers ...
    (Linux-Kernel)
  • Re: + stupid-hack-to-make-mainline-build.patch added to -mm tree
    ... which uses the hypervisor timer emulation instead of real hardware. ... clockevents doesn't really make it easier nor harder as far as init goes. ... Certainly, clocksource/clockevents/NO_HZ solves many of the problems (basically, moving away from counting interrupts to using time sources). ... this is probably not what we'd want since it will charge time to whatever process happened to be scheduled in the guest during periods of stolen time. ...
    (Linux-Kernel)
  • Re: clock problem
    ... Ntp will also become really unhappy when chunky time slips occur ... rollover or lost hardclock interrupts is easy... ... That turned out to mainly be due to the same 8254 timer being ... really a good idea to use it as a timebase. ...
    (freebsd-stable)
  • Re: Vartick in PXA255
    ... OS Timer, and to half a period, the maximum forward schedule time ... priority of your tick timer e.g Timer0? ... gpio line in your ISR routine when you get a timer match and probe it ... other interrupts that that take longer than a ms to service. ...
    (microsoft.public.windowsce.embedded)
  • spurious timer overflow interrupt issue
    ... I have a problem with software timer interrupt status on the i8096; ... 's/w timer 0' interrupts are replaced by 'timer1 overflow' interrupts ... No where in the code is 'timer1 overflow' interrupt ...
    (comp.arch.embedded)
Quantcast