Hello friends,
I've completed the test with the code and have not had any problems so far, will continue to test and if they notice something new.
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[QUOTE=Bill Legge;76621]I'm using a PIC18F8722 at 40 MHz to display data on 7-Segment displays.
There are 8 digits on each display
Each display is driven by a MAX7219 driver.
Initially, I had three displays, each on it's own port - all worked OK.
Then, to save ports, I daisy-chained the displays (Data_out of one MAX7219 to Data_in of the next). Clock and Data in parallel to all three MAX7219
Initially, all worked Ok with this chain and then:
1. After a few minutes, the third display (last in the chain) went blank.
2. Over the next half hour the second display dimmed and finally turned off.
3. Then the first display froze on '88888888'
The voltage without the displays connected in 4.97 and with all three displays connected it is 4.94, so i don't think suppy voltage is the problem?
Too high a load for the port?
Recompiling to run at 10 MHz makes no difference.
The connections between the PIC and displays is via 10-way IDC and ribbon cable.
Anyone experienced difficulties daisy-chaining displays/MAX7219?
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