SPI is a low-level 3 or 4 wire serial bus interface with clock (SCLK), data in (MISO) and data out (MOSI). The fourth wire is a Slave Select to uniquely select a device on the bus. This signal is usually active-low. Slave Select, Chip Select, CS#, SS# stand for the same function, typically. Be ...

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Relation between SPI, clock rate and data bits in microcontroller

I am working on a project which requires a UHF RFID Reader IC AS3993 having an 8 bit Reader MCU. And an externally connected LaunchPad (SimpleLink LAUNCHXL CC3200) for data transfer which works at 16 ...
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35 views

Drive logic signals when power might be off

I'm designing a board that interfaces two systems with an SPI signal. Each system has a 5V power supply, and I have access to both supplies, but either supply may be turned off at any time. How should ...
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1answer
38 views

MSP430 USCI - Are the interrupt flags still active when interrupts are explicitly disabled

I am using an MSP430 USCI in SPI mode. I would like to confirm my understanding of this: If UCTXIE and UCRXIE are explicitly disabled when the interface is initialized after UCSWRST is cleared the ...
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1answer
49 views

STM32F10x SPI - No Clock

I'm trying to get basic SPI operation working on an STM32F107VC chip using the WaveShare Port107 development board. I'm trying to initialise SPI1 which resides on PA4-PA7. I'm attempting a simple ...
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51 views

NSS pin goes high immediately

I'm working on a simple project with stm32f0. the project is when I push the button on the board, the SPI1 of the MCU should send the data. all things work nicely but there is a problem. look at the ...
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25 views

ATmega8 to MCP23S17 SPI I/O Expander not working

Since three days I'm having the problem that I can not talk to my MCP23S17 SPI I/O Expander from my ATmega8. I've double ...
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36 views

Configuring SPI on PIC16LF1827

Has anyone encountered problems getting SPI up and running on a PIC? I'm using a PIC16LF1827 and am trying to output data via SPI to what will eventually be an LCD graphics screen. The PIC will be the ...
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27 views

SPI Bus Clock Slew Rate

I am interfacing LPC1768 SPI bus and SST25VF016B SPI Serial Flash. Flash is 50Mhz, and these are the values I copied from SPI Flash Datasheet. page 24. FCLK (Serial Clock Frequency) 50 MHz TSCKH ...
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42 views

SPI TX Error on STM32F4xx

I have tried posting this question on the ST forums but have not seen any traffic on it so I figured I would try here. Background STM32F407IGT processors SPI2 peripheral being serviced by DMA ...
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3answers
72 views

What is SPI Interrupt (SPIE) in SPI control register?

I have been trying to understand SPI Interrupt i.e. what does it do and why is it used ? Reading about it on the web has not helped me. Can some one please explain it in a simple terms ?
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74 views

FATFS porting on STM32F103 SPI Flash

I have ported FATFS for Free RTOS on STM32F103 SPI Flash of 32 Mbit. In a demo Application I have successfully created a file, written a file, and read back from the file. My requirement is like I ...
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31 views

Using an LPC812 to relay/transform SPI commands

I'm trying to use the LPC812 as a SPI relay between an FPGA and a new FPAA. The purpose is to make the hardware backwards compatible with old firmware by taking old SPI commands from the FPGA and ...
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71 views

Switching a relay through a wireless connection

I want to create a circuit which will wirelessly drive a relay. I only have a little experience with Arduino. I know what peripherals I need, but I don't know what micro-controller to use. I made a ...
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112 views

What are these pulses?

To continue of this question... I figured out the main problem and now I have an odd problem. at first, let me to put the codes. "Main.c": ...
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3answers
92 views

How can I emulate two analog joysticks (potentiometers) with an Arduino?

I have a quadcopter (Syma X5C) that I really want to control with an Arduino. Since I have the ability to write programs to my Arduino to make the quadcopter fly autonomously, I want to modify my ...
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2answers
106 views

Sharing Clock and Data for 74HC595 and CD4021B Shift Registers?

Can output shift registers (74HC595) and input shift registers (CD4021B) share the same clock and data lines on Arduino using SPI, with different latch pins "activating" either chain for input or ...
2
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1answer
53 views

SPI communication - bits per second vs Hz

I have been reading more and more about bandwidths and frequencies to try to solve the following problem, but I am only ending up more confused. (I have limited electrical/signals background.) I ...
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1answer
39 views

Problems connecting differential ADC to SPI chain [duplicate]

I need to connect 3 devices with SPI in a daisy chain configuration.1 master 2 slaves. the first slave is typically connected to the master: SCK-SCK MOSI-MOSI CS-CS The second slave on chain have no ...
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1answer
44 views

NRF24L01+ IRQ Issue

I am testing the functionality of NRF24L01+ and for my purposes I have configured it as PTX, No Auto ACK. I am able to communicate with the chip just fine and able to configure all the registers ...
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227 views

Cascading several SPI devices

Is it possible to cascade several different ICs on the same data line, in order to use less CS pins, by tying the digital output of each to the digital input of the next? I am familiar with this ...
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2answers
232 views

SPI1 doesn't work

I'm working on a simple project. I want to send a string. the string is "Rohalamin". the second board after recieve the string should turn on the LED. the program for first board is (the MCU for ...
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59 views

Microcontroller SPI Using DMA with Seperate Chip Selects

I have a microntroller that has DMA (Direct Memory Access) connected to 4x identical external ADCs. All ADCs use a common conversion clock, and have their sampling synchronized. The ADCs have a data ...
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2answers
81 views

How to put a 74HC165 on an SPI bus?

If I want to read a (bunch of) 74HC165 chip(s) over an SPI port on a microcontroller, this is simple enough. Connect them through Q7 to DS on each, apply the final Q7 to MISO, notCE to SS and CP to ...
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56 views

STM32F0 Help setting SPI

I am trying to setup the SPI. I followed the logic from other tutorials but with no success. Can someone point me in the right direction? ...
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33 views

AVR SPI Issue (No data being received from slave)

I am trying to communicate to NRF24L01+ radio module using SPI on ATMega328. When things did not work out, I started analyzing the SPI signals using my logic analyzer. The SPI it set for 1Mhz, MSB ...
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73 views

How can we find the clock frequency (SCK) set by master from slave in SPI

How can we (in software, no probing using CRO) know what clock frequency the Master applies from slave (assuming I have no prior information of this). In general I program the Div_Reg register and I ...
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33 views

SPI Slave Frequency Setup

This question is in regards to a configuration where I want to setup a half-duplex SPI bus, with a master outputting a clock at 1MHz. Does the slave need to know that the clock coming in will be ...
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55 views

AVR SPI Loopback test

I would like to do a loopback test on my ATMega328 to ensure that the code I am writing (while learning SPI) is working fine. To do this I would place a jumper between the MOSI and MISO pins. What ...
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1answer
44 views

netduino SPI stops clock after write on WriteRead()

I am having an issue where the SPI bus on my netduino stops the SCK clock generator after the write has completed on a WriteRead() method. Because of this, the device (a Microchips 25LC320 EEPROM ...
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1answer
90 views

Arduino SPI connection WHO_AM_I register on IMU

I have an inertial measurement unit (IMU) sensor that communicates over SPI. I use Mega2560. I want to read one simple WHO_AM_I register. On documentation: ...
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3answers
119 views

Can several CS pins be multiplexed with a shift register?

When sharing a SPI data line between several ICs and an Arduino, what exactly are the frequency constrains of the CS pin? Can I use a shift register to multiplex the CS pins (thus only requiring one ...
2
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0answers
100 views

Are any USB-to-SPI *slave* bridge chips readily available?

I would like to interface a battery-powered device to USB, without requiring users to install drivers. Data transfer requirements are moderate, so the ~60kbytes/sec of HID mode would be fine, but I ...
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513 views

Is it normal to have SPI Clock with varying duty cycle?

I am working to get an SPI interfacing radio module on embedded Linux system. This particular module (RFM12B) is already ported onto Raspberry Pi. Now I am working on OMAP4 based systems. I noticed ...
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97 views

Trying to use SPI to communicate between dsPIC (33EP) and LED driver (LT8500)

I'm trying to setup SPI to generate PWM signals on the LED driver LT8500. Below is my code: ...
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1answer
74 views

communicating to shift register with ATmega32 without using given SPI pins

I'm trying to use an ATmega32 to communicate to a MAX7219 chip for multiplexing with an led matrix. However, I do have multiple different devices that I want to communicate with. I am trying to ...
3
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1answer
128 views

Stuck codes in samples from ADC

I am currently testing a 16-bit DAC and a 18-bit ADC. In many tests I have found the ADC to get "stuck" at codes, especially at the ends of the input range. Both the DAC and ADC operate in bipolar ...
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2answers
82 views

How can I receive multiple bytes on SPI with CS being held low?

I have an FPGA which sends out a stream of bits over SPI communicating to 3 AD8403 daisy chained together. The FPGA keeps CS low, until 30 bits (2 address bits, 8 data bits x 3) have been ...
3
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2answers
409 views

Is it possible to use an SD card without a file system?

I'm doing a project on PIC, which needs a large amount of memory to store data. I want to use an SD card as the memory storage element. I don't want any type of file system. I googled the interfacing ...
2
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1answer
113 views

Interfacing 3.3V SD card MISO output to ATmega328P

I am attempting to write data to a SD card from a ATmega328P micro controller with no luck. I've narrowed down the source of the problem to the MISO output of my SD card breakout board, which doesn't ...
3
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1answer
80 views

What does “50 ohm system” mean?

I'm looking to use the following switch to switch an SPI bus ( CLK <= 2Mhz) between two different devices. I'm reading the datasheet to see if the the frequency of the signals are going to be ok, ...
2
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2answers
142 views

Reason for choosing SPI based flash devices over I2C ones [duplicate]

I have gone through the below link which says that u-boot support three type of flash technology http://www.stlinux.com/u-boot/flash 1.Nand 2.NOR 3.SPI Serial Flash I would want to know why SPI is ...
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1answer
166 views

Raspberry Pi SPI interface with PIC-16f877A

My project is to receive sensor data at I2C of PIC and transfer it to Raspberry Pi via SPI. How can I interface my PIC and Raspberry Pi so that PIC starts receiving data as per command (SPI ...
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2answers
110 views

SPI to USB and Terminal

I would like to debug my microcntroller's program via SPI connected to PC. (Usually UART is used for debug, but I would like to debug with higher frequencies such as SPI). Can any one recomand me on ...
2
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0answers
26 views

Memory mapped peripheral on NAND bus

I have an embedded system that is not cost effective to roll a custom PCB therefore my access to certain buses are limited. I had the idea of hooking my FPGA up to the unused NAND port of the system ...
2
votes
2answers
72 views

Serial comms over 3m cable, shared with USB

I am designing a system that needs to do serial comms over a standard USB cable, as well as normal USB (but not at the same time). In other words, when plugged in to a PC it will appear as a USB ...
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1answer
47 views

SPI hookup to ATmega644

I'm trying to hookup a DS1302 to an ATmega644. The DS1302 pin 6 is a SPI I/O port but the ATmega644 has a MOSI on pin PB5 and a MISO on pin PB6. How do I go about hooking it up? This is my current ...
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1answer
79 views

How do I tackle phone-microcontroller BlueTooth communication?

I have this bluetooth module I bought on RS a while back, and I was pretty keen to set it up with an STM32L152 development board I have handy. The only thing is, I'm not really sure what steps I have ...
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1answer
124 views

74HC595 sharing SPI data line

I want to have my Arduino control several SPI slave devices, among them a 74HC595 shift register. I've having some trouble understanding how to properly handle communication - I get that the Slave ...
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234 views

STM32L1 SPI to nRF24L01 Not Working

I am currently trying to get spi communication up and running between a stm32l-discovery board (uses STM32L152RCT6 mcu) and a nRF24L01 module. I have the module connected to the discovery board via ...
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371 views

Can I use both I2C and SPI at same time with PIC16F1503

Im new to Microchip microcontrollers and I'm looking for very low cost device with I2C and SPI. I want to connect one I2C (ADC) and one SPI device (LCD). I found this very low cost device: However ...