thunderace7
New Member
Hi. I'm in the early stages of making a large led display. It will have a 40x2 driving 192 RGB less via 72 74HC595 shift registers and 72 ULN2803 drivers.
I am concerned that the picaxe output will not be able to feed the clock inputs of that many shift registers. I thought about a 2 transistor buffer (2 transistors to avoid signal inversion) but I would prefer to use a chip. Any ideas on what would be suitable, please?
I am also concerned about the speed of the display. There is a lot of data to transfer and it might take quite a while, slowing down the display. I will yet up a test on my 40x2 test rig and greatly reduced display to find out how long each display pattern takes to run before starting the next. I could then try different processor speeds and see how that affects it. If all this fails, I shall have to look at ways to speed up the program but I'm hoping to avoid that.
I am concerned that the picaxe output will not be able to feed the clock inputs of that many shift registers. I thought about a 2 transistor buffer (2 transistors to avoid signal inversion) but I would prefer to use a chip. Any ideas on what would be suitable, please?
I am also concerned about the speed of the display. There is a lot of data to transfer and it might take quite a while, slowing down the display. I will yet up a test on my 40x2 test rig and greatly reduced display to find out how long each display pattern takes to run before starting the next. I could then try different processor speeds and see how that affects it. If all this fails, I shall have to look at ways to speed up the program but I'm hoping to avoid that.