embedded

Could somebody tell me how to convert double precision into network byte ordering. I tried uint32_t htonl(uint32_t hostlong); uint16_t htons(uint16_t hostshort); uint32_t ntohl(uint32_t netlong); uint16_t ntohs(uint16_t netshort); functions and they worked well but none of them does double (float) conversion because these types are different on every architecture. And through the XDR i found double-float precision format representations ( http://en.wikipedia.org/wiki/Double_precision ) but no byte ordering there. So, I would much appreciate if somebody helps me out on this (C code would be

I'm using a STM32F4 and its SPI to talk to a 74HC595 like in this tutorial. Difference is for starters I'm using the non-DMA version for simplicity. I used STMCubeMX to configure SPI and GPIO Issue is: I'm not getting the latch PIN, that I set to PA8 to toggle during transmission fast enough. The code I'm using: spiTxBuf[0] = 0b00000010; HAL_GPIO_WritePin(GPIOA, GPIO_PIN_8, GPIO_PIN_RESET); HAL_SPI_Transmit(&hspi1, spiTxBuf, 1, HAL_MAX_DELAY); // while(HAL_SPI_GetState(&hspi1) != HAL_SPI_STATE_READY); HAL_GPIO_WritePin(GPIOA, GPIO_PIN_8, GPIO_PIN_SET); HAL_Delay(1); Things I tried: Set the

What's the best way to convert a float to a byte[4] and then back to a 'float'? I am doing this in C# .NET Micro Framework , so there is no BitConverter available for my use. I've modified the BitConverter class from a Netduino implementation to allow endianness specification (it's not the "best way", but it works). If the byte array is sent over the network, I would use BigEndian . Just a reminder that unsafe is not officially supported in NETMF. using System; using System.Diagnostics; namespace netduino { public static class BitConverter { public static byte[] GetBytes(uint value) { return

I am having a strange problem. The math libraries has been added to my makefile. # include standard C library LDFLAGS += -lc # include standard math library LDFLAGS += -lm and in the output file (.map) I can see that everything has been linked properly: LOAD c:/gnu/powerpc-eabi/3pp.ronetix.powerpc-eabi/bin/../lib/gcc/powerpc-eabi/4.3.3/nof\libgcc.a LOAD c:/gnu/powerpc-eabi/3pp.ronetix.powerpc-eabi/bin/../lib/gcc/powerpc-eabi/4.3.3/../../../../powerpc-eabi/lib/nof\libc.a LOAD c:/gnu/powerpc-eabi/3pp.ronetix.powerpc-eabi/bin/../lib/gcc/powerpc-eabi/4.3.3/../../../../powerpc-eabi/lib/nof\libm.a

I am using Anthony Williams' fixed point library described in the Dr Dobb's article " Optimizing Math-Intensive Applications with Fixed-Point Arithmetic " to calculate the distance between two geographical points using the Rhumb Line method . This works well enough when the distance between the points is significant (greater than a few kilometers), but is very poor at smaller distances. The worst case being when the two points are equal or near equal, the result is a distance of 194 meters, while I need precision of at least 1 metre at distances >= 1 metre. By comparison with a double

I found this header file for PIC microcontrollers by the name of pic1250.h and I'm unable to get the hang of some syntax used in it. The source for the file is: /* * Header file for the Microchip * PIC 12c508 chip * PIC 12c509 chip * Baseline Microcontrollers */ static volatile unsigned char RTCC @ 0x01; static volatile unsigned char TMR0 @ 0x01; static volatile unsigned char PCL @ 0x02; static volatile unsigned char STATUS @ 0x03; static unsigned char FSR @ 0x04; static volatile unsigned char OSCCAL @ 0x05; static volatile unsigned char GPIO @ 0x06; static unsigned char control OPTION @ 0x00;