R4 and R7

USB AVR Programmer and SPI interface. Adafruit's USBtinyISP.

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ogogon
 
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R4 and R7

Post by ogogon »

Greetings, colleagues!

Tell me, why in USBtinyISP are applied resistors R4 and R7?
The idea is that the buffer 74AHC125N is so well coordinated with the bus.

What are these resistors for?

Ogogon.

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adafruit2
 
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Re: R4 and R7

Post by adafruit2 »

these are resistors to prevent damage to the 74hc125 in case they are set to outputs from the Arduino side after the chip is programmed.

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