Some of you will be aware that I have written an MSF locked clock for the MBed.
It uses a 16x2 LCD display to show the time and date which works perfectly.
I have decided to take this a step further and make use of a graphical LCD display to show the same data and some extra bits and pieces.
The graphical display in question is a ByVAC BV4512 whos datasheet can be found at http://www.byvac.com/downloads/datasheets/BV4512%20DataSheet.pdf
I have written a driver for the display modelled on the TextLCD-I2C library which seems to work fine except it does seem a little slow. My driver supports all the builtin commands (pixel, box, printchar, hline, vline) and some extra functions I have written in software like circle etc).
Once complete, I'll publish the code if anyone is interested.
Back to my clock............
My clock is ticker interrupt driven by a routine that fires every 10mS. Within this routine apart from keeping correct time by counting interrupts I also call printf to display the information on the TextLCD which works absolutely fine.
When I add similar printf's to write to the ByVAC display it works but everything slows down almost as though interrupts are being missed.
I guess its an overkill updating the display every 10mS anyway but are my problems indicative of an I2C problem or simply something to be expected with the way I am doing things?
Would I be better off setting up a seperate ticker interrupt routine to update the graphical LCD less often ?
If so how would the two ticker interrupts react together, would I still be in danger of loosing interrupts here and there ?
Persumably if one ticker interrupt has fired the other cannot fire until the first has returned ?
Regards
Lynton
Mike Cowlishaw.
1 reply
Some of you will be aware that I have written an MSF locked clock for the MBed.
It uses a 16x2 LCD display to show the time and date which works perfectly.
I have decided to take this a step further and make use of a graphical LCD display to show the same data and some extra bits and pieces.
The graphical display in question is a ByVAC BV4512 whos datasheet can be found at http://www.byvac.com/downloads/datasheets/BV4512%20DataSheet.pdf
I have written a driver for the display modelled on the TextLCD-I2C library which seems to work fine except it does seem a little slow. My driver supports all the builtin commands (pixel, box, printchar, hline, vline) and some extra functions I have written in software like circle etc).
Once complete, I'll publish the code if anyone is interested.
Back to my clock............
My clock is ticker interrupt driven by a routine that fires every 10mS. Within this routine apart from keeping correct time by counting interrupts I also call printf to display the information on the TextLCD which works absolutely fine.
When I add similar printf's to write to the ByVAC display it works but everything slows down almost as though interrupts are being missed.
I guess its an overkill updating the display every 10mS anyway but are my problems indicative of an I2C problem or simply something to be expected with the way I am doing things?
Would I be better off setting up a seperate ticker interrupt routine to update the graphical LCD less often ?
If so how would the two ticker interrupts react together, would I still be in danger of loosing interrupts here and there ?
Persumably if one ticker interrupt has fired the other cannot fire until the first has returned ?
Regards
Lynton