Follow up on 'The questionable future of NFC in the wake of Apple's iBeacon'

In February, 2014 I wrote an article about Apple's lack of support of NFC and their use of Bluetooth Low Energy (BLE) based iBeacons.

Well, I was totally wrong!

Samsung introduced NFC support in the Galaxy S3 in May 2012. Apple held out until September 2014 when the iPhone 6 was released with NFC support.

Since then Apple Pay, using NFC functionality on the iPhone to make payments, has gotten huge.

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Debugging an imprecise bus access fault on a Cortex-M3

This information may apply to other cortex series processors but is written from practical experience with the Cortex-M3. Imprecise bus access faults are ambiguous, as noted by the term "imprecise". Compared to precise bus errors, imprecise errors are much trickier to debug and especially so without a deep understanding of arm processors and assembly language. Imprecise and precise flags are found in the BusFault status register, a byte in the CFSR (Configurable Fault Status Register). BusFault status register bits The definition for imprecise and precise bits is: [2] IMPRECISERR Imprecise data bus error: 0 = no imprecise data bus error 1 = a data bus error has occurred, but the return address in the stack frame is not related to the instruction that caused the error. When the processor sets this bit to 1, it does not write a fault address to the BFAR. This is an asynchronous fault. Therefore, if it is detected when the priority of the current pr

Graco Swing By Me - Battery to AC wall adapter modification

If you have one of these Graco battery powered swings you are probably familiar with the cost of C batteries! The swing takes four of them and they only last a handful of days. I'm not sure if the newer models support being plugged into the wall but ours didn't. If you are a little familiar with electronics and soldering, here is a rough guide on how you can modify yours to plug in! I wasn't sure how exactly to disassemble the swing side where the batteries were. I was able to open up the clamshell a bit but throughout this mod I was unable to determine how to fully separate the pieces. I suspect that there is some kind of a slip plate on the moving arm portion. The two parts of the plastic are assembled and the moving arm portion with the slip plate is slid onto the shaft. Because of the tension in that slip plate it doesn't want to back away, and because of the mechanicals that portion of the assembly doesn't appear accessible in order to free it. I was

Memory efficient queuing of variable length elements

In embedded environments memory can be a critical driver of the design of data structures and containers. Computing resources have been expanding steadily each year but there are still a wide range of systems with far less than a megabyte of memory. On systems with tens of kilobytes of memory, structures are often designed to be compact to maximize data density. Rather than splurging on memory aligned elements that would be faster for the processor to access, a developer will typically use types with minimal sizes based on the known range of values that the element is intending to hold. Fixed sized buffers At my day job a fixed size pool of messages was implemented to hold message data. While this achieved one design goal of using statically allocated buffers, avoiding dynamic allocations that might fail at runtime, it isn't efficient if there is a wide range of message sizes. It isn't efficient because each message uses a message buffer. With small message sizes the buff

Chris M.

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