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gcc ld and bss sections on SDRAM

Started by pozz in comp.arch.embedded2 years ago 4 replies

My platform is LPC546xx, Cortex-M4 by NXP, and the build environment is based on GCC ARM toolchain (MCUXpresso IDE). However the question is...

My platform is LPC546xx, Cortex-M4 by NXP, and the build environment is based on GCC ARM toolchain (MCUXpresso IDE). However the question is generic. The default linker script instructs linker to put bss sections (zero initialized data) in internal RAM. During startup, before main, bss sections, described in a table on Flash, are reset to zero: __attribute__ ((section(".after_vecto...


ds18B20

Started by zeneca in comp.arch.embedded2 years ago 1 reply

I am using several ds18b20 for projects, but every now an then some give temp 85.0 ° ?? without CRC error? What is causing this, is there a...

I am using several ds18b20 for projects, but every now an then some give temp 85.0 ° ?? without CRC error? What is causing this, is there a way to prevent this? Other question: Is there a way to connect ( and use) a DS18B20 (or other equivalent chip) on NodeMCU esp8266 ?? Many thanks in advances


gerber outline

Started by Hul Tytus in comp.arch.embedded2 years ago 2 replies

Ospark.com's quote section took a gerber .zip file (generated by Eagle version 3.5) and said it couldn't find the board outline. It showed...

Ospark.com's quote section took a gerber .zip file (generated by Eagle version 3.5) and said it couldn't find the board outline. It showed a few other problems too which have been fixed, thanks to several people showing working gerber code. Oshpark's need for a different form of board outline seems to be the only remaining difficulty. I'm hoping someone who has used Oshpark (or 4p...


WiFi module

Started by pozz in comp.arch.embedded2 years ago 10 replies

I need to develop a custom board with WiFi connectivity and a UART(RS485). The UART will be connected to a proprietary device with a...

I need to develop a custom board with WiFi connectivity and a UART(RS485). The UART will be connected to a proprietary device with a proprietary protocol, no problem on this. The board should connect to a MQTT server through WiFi. I don't know if I will choose a "transparent" WiFi module, implementing all TCP/IP stack and MQTT protocol on the host controller, or choose a "full-featur...


Recommendation: Cheap (free!) IoT cloud service

Started by Chris in comp.arch.embedded2 years ago 11 replies

I'm setting up a household water-tank level sensor that I'd like to be able to monitor from (practically) anywhere to a mobile device or remote...

I'm setting up a household water-tank level sensor that I'd like to be able to monitor from (practically) anywhere to a mobile device or remote PCusing the above-mentioned ESP8266-based setup. The device is sampling at 5min intervals, each sample is a single integer range 0 - 230 (cm of water height). Also toggling a 'heartbeat' boolean variable to indicate it's still alive. Just


Unit testing frameworks for embedded c

Started by pozz in comp.arch.embedded2 years ago 2 replies

Until now, I was not be able to arrange a full unit testing for any of my projects, but I want to invest some time to learn this method of...

Until now, I was not be able to arrange a full unit testing for any of my projects, but I want to invest some time to learn this method of development. There are plenty C unit testing frameworks out there. I think the most used are Unity[1] and Cpputest[2]. It seems to me others aren't oriented to embedded and/or C language (but C++). I read many comparisons among unit testing framew...


Gerbv rant

Started by Johann Klammer in comp.arch.embedded2 years ago 1 reply

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...

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?

Started by pozz in comp.arch.embedded2 years ago 45 replies

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...

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?

Started by pozz in comp.arch.embedded3 years ago 8 replies

In 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

Started by Hul Tytus in comp.arch.embedded3 years ago 12 replies

Anyone 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


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