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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Connecting GPIO and SPI signals via cable

There is a requirement in one of our systems to transfer signals from one board to another board in the same system. The signals are GPIOs and SPI lines from I.MX6 processor and it is in 3.3V ...
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1answer
17 views

Hy28B display with STM32

I'm trying to get this Hy28b display work with my stm32f103 MCU. Somehow the display doesn't respond. I've found out I cannot communicate with it, my SPI setup is the following: ...
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40 views

SPI always returns null while reading

We need some help in SPI protocol. We've been using an AVR microcontroller ATMega324PA (DIP) and an ADXL344 accelerometer (QFN Breakout). Both chip operates at 1.8V and supports I2C & SPI. Lately ...
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37 views

SPI interface using pic with cc2500

Datasheet of cc2500 is here: http://www.ti.com/lit/ds/symlink/cc2500.pdf . I looked at the SPI timing diagram on page 22. I have gone through the datasheet of cc2500 and understood that. idle state ...
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1answer
44 views

SPI Interrupt Handler delay in STM32F303?

I'm working with an STM32F303 microcontroller configured in slave mode running at 72 MHz, and I've come across some strange behavior that I'm trying to track the origin of. The master first sends ...
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1answer
94 views

Writing to SD Card cheaply

So, here's the scenario: I have an Arduino and an SD card. Unfortunately, I don't have one of the fancy shields, and I don't have the time to order one. As we know, Arduinos run on 5V, and SD cards ...
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1answer
85 views

Daisy Chaining ADC Sensors

I'm creating a grid of 200+ pressure sensors and need a clean way to get their values back to the master controller without a mess of wires. To me it seems like daisy chaining all the sensors ...
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1answer
36 views

STM32F2xx: Data from SPI Slave to Master

I have a STM32F2xx connected to a FTDI UM232H using SPI, STM32F2xx will be configured as SLAVE and FTDI will be configured as MASTER My scenario is this, I am getting data in STM32F2xx, and when I ...
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2answers
88 views

Understanding SPI

I have some problems understanding SPI: I am currently using STMF2xx to connect with FTDI UM232H, I will configure my STMF2xx into slave and FTDI into master. But, I am having problem getting the ...
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41 views

AT86RF212b connections

I'm trying to communicate at86rf212b with atmega328 , I have connected all SPI connections( MISO, MOSI, SCk, SS), IRQ, SLP_TR and RST with suitable 5v/3.3v conversion (74hc4050) and trying to read ...
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2answers
32 views

Atmega16 SPI to clock out 32bit data

I am very new to AVR and even for coding of micro-controllers. I wanted to shift out 32 bit data on SPI from a Atmega16 to a 32 bit shift register. The shift register in not an SPI compatible device. ...
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72 views

Is a file system something that is implemented in hardware or software?

The context of this question is that I would like to be able to take an SPI flash IC and store audio files on it. The reason I need a file system, specifically FAT, is because I'm using an OGG Decoder ...
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37 views

Computation capacity for a sound localization and tracking system

I'm working with Raspberry Pi and the Generalized Cross Correlation - Phase Transform (GCC-PHAT), i want to do synchronized sampling on 6 signals of 6 microphone amplifiers. The Raspberry Pi has no ...
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61 views

Raspberry PI's SPI over RS485

I'm trying to understand how to connect a SPI device (a mifare RC522 RFID board) over long distance to my RPi via SPI. I searched and find I could connect those via SPI over RS485 using a MAX490. ...
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27 views

smartcard and smartcard reader data transmission

I have a bunch of smartcards. I going to build a sniffer device that communicate with COM port to do MITM attack just for fun and for testing and upgrading my knowledge in this field. I appreciate if ...
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2answers
64 views

What is launchpad's I2C & SPI voltages?

Does anyone know what voltages TI Launchpad's I2C and SPI run at? I think it is 3V3 from a comment on a post, but can't be sure.
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1answer
75 views

Full duplex SPI Master using DMA - STM32F105

I'm trying to write a SPI driver for an STM32F105, using DMA functionality. I'm using ST's Standard Peripheral Library. I'm not using interrupts. I can talk to the destination device if I use standard ...
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1answer
77 views

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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2answers
39 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
42 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 ...
2
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1answer
69 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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2answers
66 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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1answer
36 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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1answer
49 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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1answer
29 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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64 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
80 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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1answer
111 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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34 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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votes
1answer
96 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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1answer
135 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
107 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 ...
3
votes
2answers
142 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
votes
1answer
58 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
43 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 ...
0
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1answer
54 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 ...
4
votes
2answers
238 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 ...
3
votes
2answers
247 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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0answers
71 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 ...
3
votes
4answers
115 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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1answer
84 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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0answers
37 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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votes
1answer
77 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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1answer
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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0answers
66 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 ...
0
votes
1answer
53 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 ...
0
votes
1answer
100 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: ...
3
votes
3answers
127 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
votes
1answer
118 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 ...
5
votes
3answers
529 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 ...