Cascading 7219 chips
Need some help with code around the 7219 chips. (Bear with me as I’m still learning the stamp language). I’m basing my project on Jon’s NV article that was published a couple of years ago, but have modified it with 2 5x7 matrix’s and 2 7219 chips. What my end game is to do is take a text (let’s say “Hello World”[noparse];)[/noparse] string a scroll it horizontally across the 2 displays. With Jon’s code, I can get the same data (right now just numbers)·on both displays and other combinations of differet data on the 2 displays.
I think I’m running into 2 issues, the 1st is to lookup the column data for each character in the string from eeprom. The next issues is to take that data and loop across it column by column and have the code output 10 columns (5 columns each) at a time to the 2 chips. Any guidance would be great.
I think I’m running into 2 issues, the 1st is to lookup the column data for each character in the string from eeprom. The next issues is to take that data and loop across it column by column and have the code output 10 columns (5 columns each) at a time to the 2 chips. Any guidance would be great.
Comments
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Chris Savage
Parallax Engineering
So when your pointers are initially set one will be at the address Digits.· The tail pointer will be at Digits + 15.· You will have to output this data as two blocks and then increment your pointer.· If I were doing it I would probably copy Digits into an index variable and used fixed offsets for each block.· So my code (pseudo-code) might be something like:
The Output_Digit routine would SHIFTOUT the data in two passes then pulse the LOAD line.·
Granted I haven’t tested this, but at first glance this should work…you could experiment from there and post a follow up for any additional help you need.· This is just what popped into my head considering your needs. This concept is also simplified for digits, not row/column data.
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Chris Savage
Parallax Engineering