Search found 263 matches

by viskr
Sat Nov 11, 2017 10:22 pm
Forum: New Product Ideas
Topic: reviving the BASIC stamp
Replies: 0
Views: 419

reviving the BASIC stamp

I've got a Kickstarter project going (and now funded) to bring new components to the old Parallax BASIC stamp. It was a good product in its day 20 some years ago, but was a dead end. I propose adding a USB embedded ARM in the same form factor and pin out and bringing that to market as an open source...
by viskr
Mon Dec 01, 2014 5:23 pm
Forum: Everything ARM and LPC
Topic: flash memory option for ARM
Replies: 2
Views: 1601

Re: flash memory option for ARM

I'll second Steve's suggestion. The questions you need to consider are- How much data changes and how much has to be written when power goes away? Or is it something you are posting as the program is running. You may not have enough time to write to a Flash style memory if you have limited warning o...
by viskr
Mon Nov 24, 2014 1:44 pm
Forum: Everything ARM and LPC
Topic: LED and Push button problems in LPC 2119
Replies: 13
Views: 3331

Re: LED and Push button problems in LPC 2119

The LPC2148 is a superset of the LPC2138, which we have a set of gcc tools configured for. If you don't have a JTAG connection or debugger, you should include a small monitor into your C program, something we routinely do. Yes this is kind of old school, but it lets you read and write memory locatio...
by viskr
Wed Nov 19, 2014 5:18 pm
Forum: Everything ARM and LPC
Topic: LED and Push button problems in LPC 2119
Replies: 13
Views: 3331

Re: LED and Push button problems in LPC 2119

I can assure you IOSET and IOCLR work on the LPC2119. The part has been shipping for probably 10 years, and millions in the field So ignore the button issue, you should be able to set a pin high with IOSET is a simple program. If you can't then you have a define wrong or something similar. If you ar...
by viskr
Wed Nov 19, 2014 6:31 am
Forum: Everything ARM and LPC
Topic: LED and Push button problems in LPC 2119
Replies: 13
Views: 3331

Re: LED and Push button problems in LPC 2119

Switches bounce which means they dont go from 0 to 1 once per switch, but can do it many times before settling. Does your code expect that?
by viskr
Tue Nov 18, 2014 5:29 pm
Forum: Everything ARM and LPC
Topic: LED and Push button problems in LPC 2119
Replies: 13
Views: 3331

Re: LED and Push button problems in LPC 2119

Are you sure you want to do a IOSET1 |=(1<<16); The purpose of the set/clear registers it to write a 1 to bits you want to SET/CLEAR and leave the rest alone. Typically I never do |= operations on those registers. As in some NXP ARMs reading the SET register will return the pin state, some NXP ARMs ...
by viskr
Sun Aug 03, 2014 5:08 pm
Forum: MSP Microcontrollers
Topic: Transistors to drive LEDs
Replies: 2
Views: 1727

Re: Transistors to drive LEDs

When you are driving LEDs or loads that are typically on or off, you just want to saturate the transistor. As to why they chose the PN2369, you would have to ask the author as it is not very common. A more common choice would be a 2N2222 which is made by everyone and can be found lots of places incl...
by viskr
Mon Dec 02, 2013 7:06 pm
Forum: PIC Microcontrollers - Software and Hardware
Topic: Should we use malloc in MCUs?
Replies: 9
Views: 2091

Re: Should we use malloc in MCUs?

In MCUs with real small memory footprints, just managing the malloc/free can take up more space and time than it turns out to be worth. Not to mention it is notorious for introducing bugs in the garbage collection. A much better strategy is to share a memory space between processes where you know th...
by viskr
Thu Oct 31, 2013 11:36 am
Forum: Projects
Topic: Help with dual rail power supply
Replies: 3
Views: 970

Re: Help with dual rail power supply

As you've got an ICL7660, I'd go with that to generate the -12V. The V4580L will operate up to +/-15V supplies. Just make sure your 12V supply really is 12V and not a lot more (which it might be if it is just a cheap linear walwort). In any case you will have to filter the switching noise from the s...
by viskr
Mon Oct 14, 2013 7:09 pm
Forum: Projects
Topic: Is this possible?
Replies: 1
Views: 328

Re: Is this possible?

Yes this is quite do-able. Actually would be a pretty good first project for someone. Start with a red board, https://www.sparkfun.com/products/11575 Add an LCD, https://www.sparkfun.com/products/11851 And write some software. The question then is, do you need it to be on when the PC is off, that me...
by viskr
Wed Sep 11, 2013 6:02 pm
Forum: Everything ARM and LPC
Topic: STM32 maximum GPIO speed?
Replies: 4
Views: 5166

Re: STM32 maximum GPIO speed?

The LPC2148 is going on 8 years old now, so there are faster parts in NXPs quiver.

The LPC43xx line has clock rates of 204 MHz and the FIOs will probably toggle 3x the LPC2148. It also has a SerialGPIO that is a bank of configurable shift registers that run up to the 204 MHz rate.
by viskr
Wed Sep 04, 2013 7:50 am
Forum: SparkFun Product Questions
Topic: RTC with Supercapacitor Recharge
Replies: 40
Views: 8989

Re: RTC with Supercapacitor Recharge

Just FYI From my experience most PCs will limit current to 500 mA, some even limit it more, as according to the USB spec the device is suppose to consume less than 100 mA unless it requests more from the host. Most USB hubs don't care what kind of power you try to suck out of them. I use an older De...
by viskr
Wed Aug 21, 2013 1:57 pm
Forum: SparkFun Product Questions
Topic: What is the best ARM solution for new project?
Replies: 1
Views: 355

Re: What is the best ARM solution for new project?

The current part I like is in the LPC43xx family from NXP, dual core, 200 MHz Won't have 4 SPIs, not sure I've seen that anywhere, but usually you just use 1 SPI and multiple SSEL Not sure you'll get all 8 PWMs, but 4 and probably 6 can be done in that part I haven't seen 2 DACs on any micro, that j...
by viskr
Wed Aug 21, 2013 8:15 am
Forum: SparkFun Product Questions
Topic: Smart Camera
Replies: 8
Views: 1041

Re: Smart Camera

This looks like what the doctor ordered

http://www.kickstarter.com/projects/254 ... ion-sensor

I've used the multi-core 200+ MHz LPC4330, truly an impressive performing part for less than $10 even in small quantities.
by viskr
Wed Aug 21, 2013 7:18 am
Forum: Arduino
Topic: Estimated duration with battery
Replies: 2
Views: 526

Re: Estimated duration with battery

The current draw is not 0 when in standby mode for any microprocessor. So you have to add that into the total, and the lower that is the longer you will have. That mode can vary widely depending on what peripherals are running. This is where all the vendors are competing to get that power down mode ...