A previous, forgotten and unfinished project surfaced recently which I plan to finally complete: <A href='http://www.rev-ed.co.uk/picaxe/forum/Topic.asp?topic_id=6245&forum_id=30&Topic_Title=IF%2BPICAXE%2B%2526gt%253B%253D%2BSimple%2BTHEN%2BControl%255FRGB%255F&forum_title=No+new+posts+please%21+22' Target=_Blank>External Web Link</a>
The above discussion ended with me intending to use 3-MAX7219 to drive my 8x8 RGB CC LED Matrix. After breadboarding, it became clear this would not work as the PWM generator on each of the 3-7219s were not sync'd and a call to technical support confirmed I would not be able to use these devices as intended (they would work if I used discrete LEDs, but this is not an option).
After a brief think, I realized this project could be done with just 1-7219 and 3 synchronized PWM generators!
I planned on using an 08M running a software loop to generate the required signals, but a recent posting about glitches has me concerned:
<A href='http://www.rev-ed.co.uk/picaxe/forum/Topic.asp?topic_id=7469&forum_id=31&Topic_Title=Pwmout%253A%2BGlitches%2Bwhen%2Bused%2Bin%2Ba%2Bloop&forum_title=PICAXE+Forum' Target=_Blank>External Web Link</a>
Although I am not driving a motor and the glitches may not be seen on my LED matrix, I was curious of how you guys would approach generating 3 glitch-free signals from a single 08M. The only other function of this 08M is to respond to an external interrupt, which is used to re-program the duty cycles of the 3 signals. For this test, updates will only occur every 5 seconds or so.
Richard
The above discussion ended with me intending to use 3-MAX7219 to drive my 8x8 RGB CC LED Matrix. After breadboarding, it became clear this would not work as the PWM generator on each of the 3-7219s were not sync'd and a call to technical support confirmed I would not be able to use these devices as intended (they would work if I used discrete LEDs, but this is not an option).
After a brief think, I realized this project could be done with just 1-7219 and 3 synchronized PWM generators!
I planned on using an 08M running a software loop to generate the required signals, but a recent posting about glitches has me concerned:
<A href='http://www.rev-ed.co.uk/picaxe/forum/Topic.asp?topic_id=7469&forum_id=31&Topic_Title=Pwmout%253A%2BGlitches%2Bwhen%2Bused%2Bin%2Ba%2Bloop&forum_title=PICAXE+Forum' Target=_Blank>External Web Link</a>
Although I am not driving a motor and the glitches may not be seen on my LED matrix, I was curious of how you guys would approach generating 3 glitch-free signals from a single 08M. The only other function of this 08M is to respond to an external interrupt, which is used to re-program the duty cycles of the 3 signals. For this test, updates will only occur every 5 seconds or so.
Richard