Couple of questions for Jon W. on LED's
slotcarz
Posts: 30
Hey Jon.
I have a couple of questions for you.
I am having a heck of a time understanding things. Hope you can help.
This is from your tut for the NV docs I D/L'd.
Column #70: Let There Be LEDs
The Nuts and Volts of BASIC Stamps (Volume 2) • Page 379
"There’s a bit of an inconsistency in the MAX7219. To set the scan limit to five columns, we’ll put a four in the scan limit register ($0B). After that though, columns are addressed as one through five. We’ll need to remember that when writing our code."
Isn't ($0B) 11? I'm trying to understand the hex system and that is throwing me for a loop..
Also, will changing this scan limit·value in the code help with the scrolling of my LED's so they move across all instead of scrolling in their own 7x8 matrix?
thanks...
Jeff
I have a couple of questions for you.
I am having a heck of a time understanding things. Hope you can help.
This is from your tut for the NV docs I D/L'd.
Column #70: Let There Be LEDs
The Nuts and Volts of BASIC Stamps (Volume 2) • Page 379
"There’s a bit of an inconsistency in the MAX7219. To set the scan limit to five columns, we’ll put a four in the scan limit register ($0B). After that though, columns are addressed as one through five. We’ll need to remember that when writing our code."
Isn't ($0B) 11? I'm trying to understand the hex system and that is throwing me for a loop..
Also, will changing this scan limit·value in the code help with the scrolling of my LED's so they move across all instead of scrolling in their own 7x8 matrix?
thanks...
Jeff
Comments
The MAX7219 can handle an 8x8 matrix, so if you want something wider than that you must update the code such that the end column data on one module gets pushed intot he starting column ata of the next. It can be done, but is not trivial and goes beyond changing the scan limit value.
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Jon Williams
Applications Engineer, Parallax
Dallas, TX· USA