DIYEFI.org Forum

Ok

again, pardon my ignorance, does XDP put IO pins into high impedance state when bootloading?
If it does, i may have (abstract at this point) solution up my sleeve

Alex

Thanks for the link (maybe this convinces me to finally get some scope solution) my specific case had a 5V part (MCP2515) outputting the signal into 3.3V part (AT91SAM7) through the 1K res. In addition, i am thinking i had data rate of about 10Mhz at the time (which may helped the negative effect) I...

Not sure whether it was offered/discussed before (i looked), but why not think of implementing a smart polarity detector as a part of bootloader/firmware (do it on each startup, for instance)? algo is something like this: - assert default level as off - quickly measure the current going through the ...

Ah, makes sense now

don't have oscilloscope, but perhaps the signal was simply 'slewed'. I would be surprised to find out that carbon resistor would introduce significant amount of inductance or capacitance

Contrary to suggestions i've received, I personally experienced problem using 1K series resistor to protect an IO leg. While not on freeEMS MCU, but on ARM, even though spec'ed as 5V tolerant, i tried to protect an SPI input leg of the 3.3V MCU while connecting it to an 5V device (so 5V to 3.3V leve...

my 2 cents: - perhaps the discussion about power persistence (after shutoff or other causes of power off) should be clearly separated to: a) MCU controlled: the intentional delay for various reasons before power is shut to the MCU and/or other devices , and b) MCU uncontrolled: a protective circuit ...

what voltages/currents are you looking for?

i plan to make some power supplies based on LM2678 (5A), they have 3.3, 5, 12 and adjustable Voltage versions - get these chips for free as samples from National (i think)

it looks like a nice unit tho if you have spare $100

Alex

not sure if the forum section is correct, but.. came across this new affordable mixed signal micro ($7-8 for 1k) with onboard CAN and all kinds of analog signal blocks/periphery - perhaps useful for a low cost analog signal CAN node http://www.eedigest.com/ecn/MAXQ7666-Highly-integrated-compact-solu...

My opinion: It's all about transformations/mappings really. The general model is basically one big transformation/mapping (sometimes with a feedback mechanism), which takes a number of inputs (MAP, CLT, TPS, etc) and spits out final outputs like injection duration and spark advance angle. Furthermor...

Here is a good "intro into various types of micro's" article i came across http://www.ferret.com.au/c/Microchip-Technology-Australia/The-diverse-world-of-microcontrollers-n692721 I am also discovering this wonderful world. currently looking at ARM7, Parallax propeller. Cortex-m3 and PSoC a...