uC - Programming

[spirilis]

The pin count tends to be excessive in the higher end processors. I been using the DSPIC for my DIY projects, primarily because they are available in user friendly packages.

The RX looks like a very capable chip. I'd be interested in what you think of the development environment. The kit would be much more useful if it allows the onboard JTAG debugger to be used on other chips.

That is a huge hit against it too, the JTAG piece. I think the cheapest option for programming your own board is around $120 (mouser prices) ... $60 J-Link EDU edition + $60 RX adapter for it. Yuck.

Never played with the Microchip processors myself, I know they're very popular though. My latest work has been with the MSP430 (TI LaunchPad) and I got a project in the works for that atm... external grill/smoker temperature monitor (basically 2 thermocouples read once every 5 minutes and transmitted via nRF24L01+). I do like how TI rolled out the Value Line with 14-20 pin DIP parts. The SMD ones are 0.65mm pitch 2-side (TSSOP) and not too hard to solder.

 

[spirilis]

Looks like TI is gearing up for their new Stellaris Launchpad next month... introductory price $4.99, includes an ARM Cortex-M4F with what sounds like a shitton of stuff (8 UARTs, 1 USB-OTG, up to 27 timers? curious what that means "up to"...)
http://www.youtube.com/watch?v=RpnUvwt2Oq4 -- main TI Stellaris Launchpad prerelease site
I see some JTAG pins on the emulation header of that board, not populated but I'll bet that's an externally-usable JTAG...

The "BoosterPack" form factor TI started with the MSP430 LaunchPad is apparently an emerging standard of theirs, they have a document on their processors wiki detailing how it works; there are 20-pin, 40-pin and 80-pin standards for boosterpack add-ons. Stellaris Launchpad will use the 40-pin version while the original MSP430 launchpad uses the 20-pin version. They also rolled out a C2000 Launchpad last month, $17, the C2K is a 32-bit MCU with DSP coprocessor built in ... It is its own thing, not ARM compatible or whatnot. I don't honestly see any reason for me to learn it since I don't mess with that kind of math-intensive stuff.

 

[Not_Me]

That is a huge hit against it too, the JTAG piece. I think the cheapest option for programming your own board is around $120 (mouser prices) ... $60 J-Link EDU edition + $60 RX adapter for it. Yuck.

Evaluation boards often have a built in JTAG unit that can be used with external processors. They usually don't advertise it because they want to encourage you to buy the standalone unit. In many cases, they don't go out of their way to cripple it. It's up to you to find out.

The one on the MSP430 is useable with external value line processors. I tried it. You just need to solder make some minor mods to the board. Note that there is an error on earlier versions. I forget what it is, but it wasn't hard to figure out.

The C2000 is actually a type of DSP. So are Cortex M4's. The $17 C2000 launchpad is exceptional because it has an isolated JTAG on board. I wonder if it is compatible with TI ARM processors.

 

[entropie]

Someone got his hand on that one already: http://www.raspberrypi.org/ ?

 

[spirilis]

Nah, I have a coworker itching to buy one soon but I think I got my hands full with the 8/16-bit world still.
It's getting a lot of play in the blogosphere though ... might match Arduino in eventual hardware/hobby support.

 

[spirilis]

So as an adjunct to my post above about the Renesas RX board, the professor (Dr. James Conrad) who wrote that book about it also has a full semester of lectures up on youtube about it--his Embedded Systems Course:
http://www.youtube.com/user/stiquitojmconrad/featured

Watched/skimmed the first 3 lectures, lots of basic stuff I already know so I am going to skim as much as possible to pick up what I need to know.

 

[spirilis]

Got my MSP430-based grill monitor external sensor boards last night... soldered one up, I used the LaunchPad FET with jumper wires to program it to blink its 2 LEDs, so far the MCU and battery/boost regulation circuitry works correctly as expected. Writing code tonight to test out the thermocouple amplifier circuits and the nRF24L01+ transceiver.

Pics:

(the Baltimore Ravens logo was at the request of my boss's boss... who's going to buy one from me once it's complete and tested)

 

[Not_Me]

Looks interesting. Is that your design? What does it do?

 

[spirilis]

Yep, my design (I used OSHpark.com for the board)... It reads 2 thermocouples every minute or 2 and relays it over RF (the cheap-o nRF24L01+ variety) to a base station attached to a server/PC indoors. Monitors the dome + meat inside a smoker/grill.

Design goals included permanent outdoor installation (it fits inside a water resistant enclosure -- http://www.polycase.com/wc-22f ) and minimal maintenance, necessitating the use of AA batteries plus a 3.3V boost regulator. This all precluded the thought of trying to rig some kind of WiFi support to make it self-contained, instead I chose the nRF24 because of its low power + cheap acquisition cost.

There is an expansion I/O port offering four GPIOs and the three Serial Peripheral Interface lines (SCLK/MOSI/MISO) to support whatever add-on gadgets I get the itch to build for it, the thought was to make this a cheap version of the BBQ Guru and related gadgets that normally cost $300+. This unit plus its base station should come in under $120 with thermocouples.

I'm hoping 2 AA alkalines will get over a year of battery life in this thing. Average power draw should be <20uA with occasional (once a minute or 2) spikes to ~15-20mA for 1/2 second.

 

[entropie]

Looks great !! What boost converter did you use ?

 

[spirilis]

Used the TI TPS61221... looked like it was optimized for these scenarios

 

[Not_Me]

Nice project. I might have use for a remote monitoring device also. I'll take a look at the parts you used.

 

[entropie]

Used the TI TPS61221... looked like it was optimized for these scenarios

Ouh yeah 5,5µA quiscient current is a luxus model, that way you really should be able to make those bats last a year.

I have lately been looking into combining an avrs sleep mode and power down states with a boost converter in one chip. As in when the load is not needed the chip will go to sleep and the conversion will stop. That way you could stop the conversion if not needed and reduce power consumption some some nA.

I am still working on my nixie clock:







Since I am no electrotechnician I have no idea tho if I placed the parts correctly on the layout and havent build some sorts of current loops, which will prevent that thing from functioning :/

 

[spirilis]

Nice, I might have to make a VFD or nixie tube-based clock one of these days... although LEDs work well enough for me generally.

I'm not too familiar with the intricate details of switching power supplies, I generally understand what they do but I leave the implementation details to the experts and buy their ICs

 

[Not_Me]

For home use, the placement is not too important. Even a breadboard would work in most cases.

 

[entropie]

My Nixie layout is done, gona see if it works. When I am lucky I get around the weekend to soldering it

 

[spirilis]

nice! I scored a freebie from someone on the 43oh forum, a launchpad boosterpack PCB plus sample chips to get a VFD tube clock working... just no tube, so I will have to go hunting for that at some point.

Also tackling the Renesas RX, approaching it methodically "one peripheral a week." Currently trying to figure out how to write & read to the 32KB Data Flash segment onboard...

 

[garbage]

Oh shit, I remember uC programming.

We had a club back in college that built robots and pitted them against other robots in our area of the country. Nobody understood deadlines and testing, so we often didn't have a working machine. Then again, neither did anyone else.

We used ATmegas because you could pretty much use straight C with them.

My role was mostly reorganizing the hell out of that club, introducing training programs for freshmen to get exposed to this stuff, etc. I'm an enabler. I guess that's in my blood.

My best personal project was a guitar pedal.

My Nixie layout is done, gona see if it works. When I am lucky I get around the weekend to soldering it

Damn, that looks pretty neat.

 

[entropie]

nice! I scored a freebie from someone on the 43oh forum, a launchpad boosterpack PCB plus sample chips to get a VFD tube clock working... just no tube, so I will have to go hunting for that at some point.

You could have a look here: http://www.tube-tester.com/sites/nixie/nixie-tubes.htm

That guy has lots of Nixies and VFDs, he fluently speaks english so you can mail him too (he just looks a bit scary)

 

[entropie]

I majorly effed up with the resistors in the layout . Looks funny tho

Need to program the chip tho still, so now test run yet. Soldering russian nixies is a bitch, took me 7 hours ....