Microcontroller Getting Heat. PIC32 CAN Bus SN65HVD1050

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dhruv_electro

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We are having chipKIT Max32 board (Board Schematic Here). We are designing CAN Bus node with it. We are having SN65HVD1050 as CAN Transceiver. (Technical Page Here). We have successfully transmitted and received CAN Frame with this. Our Schematic is attached here:



But when Program Runs and when we start receiving and transmitting the frames over bus the MCU IC PIC32MX795F512L gets heat. We needs guidance here, why does it get heat? And what we can do to prevent it?
 

I hope my suggestion may help you fix your issue.

1. Verify that your power source must provide supply voltage not more than the max input voltage that the controller can support.

2. Write a LED blink program and make it run for several minutes and check whether the controller is getting heated. Micro controller may not get heated for LED blink application. Even, it may not get heated even while handling complex protocol stacks.

3. Check for shortage between Vcc and Ground lines. Even a tiny soldering led ball may sit between controller pins and shot them. So, clean your board gently with Isopropyl alcohol and let it dry before you power on your board.
 

Anytime chip gets too hot, try to have a current limiter in debug mode.

Failure can occur from ESD , from stray noise, floating inputs, damage, exceed absolute max. voltage on any pin in spec.

If you report problem, try to measure temperature and current @ voltage, or at least say .. too hot to touch more more than "x" seconds as a measured value. Current can sometimes be measured as voltage drop on supply with series resistance of wire to measure current.

Then walk around every pin with a meter or scope and look for suspicious voltages and report.
 

Hi gopintj n SunnySkyguy,

Thanks for the reply,

We are using a ready made kit, which do not required any soldering. We just required bunch of wires. We have CAN IC Soldered on other General purpose board. We have checked the connections. The Main Kit does have regulated power supply. We also measured it fine. Yes Simple LED blink is not making the MCU Heat. Our program runs flawlessly, it sends and receive correct CAN frames. The MCU is not too hot to touch, but it is Hotter than when we run simple LED program.

We are using SN65HVD1050, it has 5V VCC and IOs, and our MCU is at 3.3V. But CAN pins on MCU are 5V compatible. Is there any fact that we are missing here?
 

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