2 Feb Atmel’s AT91SAM7X/ is a member of a series of highly The AT91SAM7X and AT91SAM7X differ only in memory sizes. AT91SAM7XAU Microchip Technology / Atmel ARM Microcontrollers – MCU kB Flash 64kB SRAM 55MHz 4 PWM datasheet, inventory, & pricing. AT91SAM7X Microchip Technology / Atmel ARM Microcontrollers – MCU datasheet, inventory, & pricing.

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Simple cheap and compact. Sign in Sign in Remember me Forgot username or password? I don’t see any code piece in the startup code tampering with the GPIO.

Can not boot from the AT91SAM7x256

It seems that I need external pulldown to compensate them At91sm7x256 very minor nit. The only disadvantage of using the pull-down resistor to overdrive the pull-up is that you have to allow for the maximum pull-up current possible over temperature and process. I know that the ULN is designed for 5V pegel, but 3,3V gives enough current to safely drive my relais. But in the meantime I’ve noticed a very dissapointing detail about the controller.


Create free account Forgot password? It turns on both FETs and can create problems. Therefor use extra transistors – they do inverting for you for proper PowerUp.

That’s what inverters are for. Protecting the IoT with Invisible Keys. I ended up using a hand full of Transistors to cover these issues properly. I was going to ask what your drive configuration was.

Looks like your PA inputs can source as much as uA of current. I didn’t find an errata in the Atmel datasheet.

AT91SAM | GPIO problem with AT91SAM7X

Of course if you want the default state to be off so it doesn’t drive the relays, then you either need to use a pair of transistors or use a PNP transistor on the high side instead of an NPN on the low. On Thu, Aug 16, at My problem is that I get a high ta91sam7x256 at power on of about 25ms, which is enough for the relais to switch.


This pulse is a flat 3,3V signal, no power up glitches or something. Introduction to Microcontrollers Mike Silva. Arduino Robotics Lonnie Honeycutt. Then the default state is for the transistor to be on and the internal pullup does not hurt.

GPIO problem with AT91SAM7X256

Welcome to the club. Embedded Software Engineer Loft Orbital’s mission is to make at91sam77x256 simple for organizations that need BTW, the English is relays.

So a 1 kohm pull-down should do the trick. The pullups are enabled on reset and are possibly powerfull enough to supply enough current through the ULN But then if you are running the relays at a higher voltage than the CPU, this won’t work either.

I’m used that GPIO come up with high impendancy and this behavour is really unexpected.