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Re: IDE for STM32

 by monkeyxpress ¦  Wed Feb 25, 2015 4:30 pm ¦  Forum: Everything ARM and LPC ¦  Topic: IDE for STM32 ¦  Replies: 4 ¦  Views: 2589

STM32CubeMX is just the stub file generator. You can do all the configuration yourself pretty easily (and if you want to do anything serious/critical, I would recommend you just do that). Sadly vendor provided 'tools' have long been plagued with endless bugs. They really just use them as shiny marke...

Re: SPI mater transmit problem

 by monkeyxpress ¦  Wed Feb 25, 2015 4:18 pm ¦  Forum: Everything ARM and LPC ¦  Topic: SPI mater transmit problem ¦  Replies: 1 ¦  Views: 1661

It sounds like you are getting glitches in the receiver. To narrow down what might be the problem I would recommend: 1. Check all polarities (CPHA and CPOL) carefully and ensure they match what the receiver expects. 2. Reduce the clock rate and confirm that the system works reliably at a lower rate ...

Re: controlling 3-wire PC fan speed and reading rpm accurate

 by monkeyxpress ¦  Fri Feb 20, 2015 7:40 am ¦  Forum: Projects ¦  Topic: controlling 3-wire PC fan speed and reading rpm accurately ¦  Replies: 2 ¦  Views: 1142

Okay could be a number of issues, but most likely it is a hardware problem: 1. The hall sensor inside the fan gets its power from the fan's power supply. Depending on the specs of this sensor it may simply be no longer working properly at the low voltage levels. If this is the case, then there is no...

Re: How to identify what LED you have

 by monkeyxpress ¦  Fri Feb 20, 2015 7:26 am ¦  Forum: Projects ¦  Topic: How to identify what LED you have ¦  Replies: 8 ¦  Views: 774

Get a 1k resistor and a 9V battery and wire them up in series with each LED. Sorry this sounds so obvious, but it is really the best way. Some multi-meters have an LED test function and this is all they are doing inside. Beyond identifying the colour you'll have to use your eyes to determine whether...

Re: How to calculate to current capability of a pcb

 by monkeyxpress ¦  Fri Feb 20, 2015 7:18 am ¦  Forum: PCB Design Questions ¦  Topic: How to calculate to current capability of a pcb ¦  Replies: 9 ¦  Views: 2571

Think about the first principles. The copper area on the PCB is just a resistive heater, and this heat needs to be removed or the board will literally fry. You want to keep the surface temp below around 60degC (I think from memory). The track width calculators just assume a thermal conductivity from...

Re: Tutorial series?

 by monkeyxpress ¦  Fri Feb 20, 2015 6:56 am ¦  Forum: FPGA's ¦  Topic: Tutorial series? ¦  Replies: 7 ¦  Views: 3891

I agree with the post so far - aim it at totally new people. It is a pretty specialised field, and not a lot of information for beginners. However, one thing I would think carefully about is the 'why'. Arduino really made embedded popular (I mean the AVR is a very old chip) because they turned embed...

Re: EEPROM writes and BOD

 by monkeyxpress ¦  Fri Feb 20, 2015 6:09 am ¦  Forum: Code ¦  Topic: EEPROM writes and BOD ¦  Replies: 7 ¦  Views: 2653

re: cosmicray's solution. This is a good approach provided you can afford to have the 'special value'. I would encourage you to have a look at the binary representation of what you're actually doing though. Essentially, you're just allocating the most-significant-bit of the value to be the validity ...

Re: EEPROM writes and BOD

 by monkeyxpress ¦  Fri Feb 20, 2015 5:33 am ¦  Forum: Code ¦  Topic: EEPROM writes and BOD ¦  Replies: 7 ¦  Views: 2653

This is a very common situation in embedded systems where you have to expect the power to go off at any time. Sometimes it is better to just put a buffer capacitor and power loss interrupt to keep the chip alive until it can complete tidy ups, but if you don't care about losing the data record then ...


 by monkeyxpress ¦  Fri Feb 20, 2015 4:42 am ¦  Forum: AVR Microcontrollers ¦  Topic: SPI BIT BANG CODE IMPLEMENTATION ¦  Replies: 2 ¦  Views: 4434

In the slave everything has to happen on the clock edge from the master (either rising or falling depending on the polarity mode). So in your while loop you just want to block until you see a clock edge, then you go do your processing (read the MOSI pin and put your data onto the MISO pin). Once tha...

Re: Too confusing to do this myself, perhaps simple for you

 by monkeyxpress ¦  Fri Feb 20, 2015 4:20 am ¦  Forum: AVR Microcontrollers ¦  Topic: Too confusing to do this myself, perhaps simple for you $$$? ¦  Replies: 2 ¦  Views: 2106

You've probably had this sorted already, but the code for doing this is very simple, and you would probably be best just getting an Arduino and reading a few tutorials. It would be cheaper and once you've figured out the basics you'll be able to quickly mess with frequency timing etc. Lots of sample...

Re: ATMEGA328P default fuses

 by monkeyxpress ¦  Thu Feb 19, 2015 10:24 am ¦  Forum: AVR Microcontrollers ¦  Topic: ATMEGA328P default fuses ¦  Replies: 2 ¦  Views: 2171

I just had a look at the datasheet. It really looks like avrdude has got the E and H bytes mixed up. If you swap these around then everything is correct and the chip is as it comes from the factory (as you identified). The numbers don't make any sense the other way around so if its a new chip put a ...

Re: Trouble recognising atmega8, fuse setting issue

 by monkeyxpress ¦  Thu Feb 19, 2015 10:16 am ¦  Forum: AVR Microcontrollers ¦  Topic: Trouble recognising atmega8, fuse setting issue ¦  Replies: 3 ¦  Views: 2217

Don't worry this happens to the best of us, even with lots of experience. I normally hook a signal generator (outputting a 0-5V square wave) and feed this into CLOCKIN through a 1K resistor to bring the chip back up until I can reset the fuses. FYI the internal OSC is pretty good if you only need ti...