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Gerbv rant
inThe Idea was to bypass the lame gui using the cmdline opts but it can't combine on export. So the second try was just translating then...
The Idea was to bypass the lame gui using the cmdline opts but it can't combine on export. So the second try was just translating then doing the 1hour-clicky-dance to combine everyhing. But as it turns out it's also unable to rotate on cmdline. (gerbv version 2.6.0) Avoid gerbv for panelizong. it is utterly hosed software. Here's my notes: combining boards dimensions: 16-d...
Makefile or IDE?
inWhen I download C source code (for example for Linux), most of the time I need to use make (or autoconf). In embedded world (no Linux...
When I download C source code (for example for Linux), most of the time I need to use make (or autoconf). In embedded world (no Linux embedded), we use MCUs produced by a silicon vendor that give you at least a ready-to-use IDE (Elipse based or Visual Studio based or proprietary). Recently it give you a full set of libraries, middlewares, tools to create a complex project from scratch ...
Function pointers: good or bad things?
inIn reply to my previous post, Paul Rubin says: "I think MISRA C disallows function pointers, partly for this reason." Are function...
In reply to my previous post, Paul Rubin says: "I think MISRA C disallows function pointers, partly for this reason." Are function pointers really bad things? Sincerely I found them useful and lastly I was using them more and more. Am I wrong? Function pointers help me in at least three situation. With function pointer I can isolate C modules from the rest of the project, so ...
navigation math
inAnyone know the method for calculating a reciever's position from the time difference between three rf pulse transmiters of known positions?...
Anyone know the method for calculating a reciever's position from the time difference between three rf pulse transmiters of known positions? This has apparantly been in use since the second world war but a description of the mathematics involved is hiding. Maybe a text on navagation methods? Hul
How to write a simple driver in bare metal systems: volatile, memory barrier, critical sections and so on
inEven I write software for embedded systems for more than 10 years, there's an argument that from time to time let me think for hours and leave...
Even I write software for embedded systems for more than 10 years, there's an argument that from time to time let me think for hours and leave me with many doubts. Consider a simple embedded system based on a MCU (AVR8 or Cortex-Mx). The software is bare metal, without any OS. The main pattern is the well known mainloop (background code) that is interrupted by ISR. Interrupts are use...
Worst case stack
inI found a nice tool[1] on GitHub. I run it on one of my embedded projects and after a couple[2] of fixes, it eventually printed some good...
I found a nice tool[1] on GitHub. I run it on one of my embedded projects and after a couple[2] of fixes, it eventually printed some good output. There were many unresolved functions, mainly from libc, C runtime, interrupts. I defined all of them in .msu, so now in the final output there aren't unresolved functions. Now there's another big problem. Many functions have an unbounded s...
decoupling the ADC reference on 16F15344
Hello, I would like to know if there's a way to output the internal adc vref(1.024 or 2.048 V) onto the vref+ pin, to attach an external...
Hello, I would like to know if there's a way to output the internal adc vref(1.024 or 2.048 V) onto the vref+ pin, to attach an external decoupling capacitor. The Datasheet is a bit unclear on this. There's a bit to connect the ext aref pin from adc vref, but I think that just uses vhatever voltage is there externally. (ADPREF in ADCON1). There's also the DAC1OE2 bit in DAC1CON0, but...
Multithreaded disk access
inAs a *rough* figure, what would you expect the bandwidth of a disk drive (spinning rust) to do as a function of number of discrete files being...
As a *rough* figure, what would you expect the bandwidth of a disk drive (spinning rust) to do as a function of number of discrete files being accessed, concurrently? E.g., if you can monitor the rough throughput of each stream and sum them, will they sum to 100% of the drive's bandwidth? 90%? 110? etc. [Note that drives have read-ahead and write caches so the speed of the media migh...
Convert 16x2 chars display to big TFT display
inI have a CPU board that interfaces to a standard 16x2 chars display, based on HD44780 controller. I'd like to replace this display with a...
I have a CPU board that interfaces to a standard 16x2 chars display, based on HD44780 controller. I'd like to replace this display with a full-color big TFT display, maybe 10", but I can't change the firmware of the CPU (because I don't have the source code and I can't rewrite it, because of cost and time). The simple idea is to create an interface between the current CPU board and t...
Are packed structs slower AND safe?
inIn one of my projects that run on a Cortex-M0+ MCU, I have a few arrays of structs. Now I need to increase the size of the arrays, but I'm out...
In one of my projects that run on a Cortex-M0+ MCU, I have a few arrays of structs. Now I need to increase the size of the arrays, but I'm out of RAM, so I'm searching for ways to save some space in RAM. One simple way is to pack the structs, for example with __attribute__((packed)) in gcc. I can save some padding bytes (that waste some memory) for each element of the array, so t...
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