poorchava
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I need to multiplex 8 7-segment displays + some leds (device panel). The problem is that i've got very limited number of data pins available for display.
Displays which i'm using are common anode, single display dies (bought them in large volume for an attractive price). I want to drive segments with serial-in-parralell-out registers 74hc164. This approach uses only 2 pins of microcontroller.
I don't know what to use to drive digits. I thought about cd4017 decade counter or cd4028 bcd-to-decimal decoder, but none of them can source enough current to drive a display with sufficient brightness. I could use some darlington array line ULN2003, but it needs to be pnp type, which is far less common and like 5x more expensive than ULN type (ULN's are npn only).
I could use shift registers for driving digits too, but i'm worried about display flickering. Has anybody tried using shift registers for driving both segments and digits?
The microcontroller i'm using is AVR (protptype is on atmega8, but final design will use atmega48-10 (the 10MHz version) in tqfp package.
Displays which i'm using are common anode, single display dies (bought them in large volume for an attractive price). I want to drive segments with serial-in-parralell-out registers 74hc164. This approach uses only 2 pins of microcontroller.
I don't know what to use to drive digits. I thought about cd4017 decade counter or cd4028 bcd-to-decimal decoder, but none of them can source enough current to drive a display with sufficient brightness. I could use some darlington array line ULN2003, but it needs to be pnp type, which is far less common and like 5x more expensive than ULN type (ULN's are npn only).
I could use shift registers for driving digits too, but i'm worried about display flickering. Has anybody tried using shift registers for driving both segments and digits?
The microcontroller i'm using is AVR (protptype is on atmega8, but final design will use atmega48-10 (the 10MHz version) in tqfp package.