auto-detecting the resolution of HD44780-based LCD modules ?
in [Embedded]
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From: Robert Roland on 13 Nov 2009 13:41 On Fri, 13 Nov 2009 16:36:27 +0100, whygee <yg(a)yg.yg> wrote: >or there could be a "configuration menu" that >sets the handling routine at power-up. An internal EEPROM byte >(think PIC) contains the type, that is changed through the menu >before changing the LCD. So no programming/flashing device >to carry. > >But if a clueless technician messes with the menu, the board is bricked :-/ You could add an emergency combination, such as holding both buttons while powering up, to get into a default 1x8 mode, which works on all displays. You would have to implement the display configuration menu in that limited 1x8 space, but I think that should be possible. A jumper could also be used to enter the config menu if that is more suitable. -- RoRo
From: whygee on 13 Nov 2009 13:21 hi ! Robert Roland wrote: > On Fri, 13 Nov 2009 16:36:27 +0100, whygee <yg(a)yg.yg> wrote: >> But if a clueless technician messes with the menu, the board is bricked :-/ > > You could add an emergency combination, such as holding both buttons > while powering up, to get into a default 1x8 mode, which works on all > displays. This "mode" is already used to get into the "menu" (plus a hardware key). > You would have to implement the display configuration menu > in that limited 1x8 space, but I think that should be possible. i've been too much spoilt by the width allowed by 1x16 displays ;-P > A jumper could also be used to enter the config menu if that is more > suitable. well it's another pin, and is is used by a standard key-enabled switch. It looks like soldering some SMT pull-down resistors is not so complex or stupid after all :-) Thanks, YG -- http://ygdes.com / http://yasep.org
From: whygee on 13 Nov 2009 23:34
Hello again, I've written a draft (incomplete, preliminary etc.) about this idea, available at http://yasep.org/~whygee/RFCpulldownLCD.html I have found a few tricks to reduce the power draw, like tying the pull-down resistors to the RS pin instead of Vss. Comments are welcome, YG -- http://ygdes.com / http://yasep.org |