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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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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57 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
84 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
74 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
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2answers
60 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
41 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
28 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
27 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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2answers
201 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
184 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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46 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
67 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
32 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
30 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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1answer
63 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
47 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
32 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
65 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
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3answers
106 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
85 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
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3answers
488 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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0answers
69 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: ...
0
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1answer
62 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 ...
2
votes
1answer
101 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
70 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
289 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
votes
1answer
80 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
votes
1answer
74 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
votes
2answers
118 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
124 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 ...
0
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2answers
91 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
24 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
67 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 ...
0
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1answer
42 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 ...
0
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1answer
70 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 ...
0
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1answer
107 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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0answers
176 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 ...
2
votes
3answers
286 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 ...
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1answer
463 views

AVR SPI slave with interrupt

For a project I want to have two microcontrollers talk to each other via an SPI interface. I wrote the following code for the slave: ...
0
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4answers
90 views

Resistors on SPI [closed]

I need to read several variable resistors (max 5 Mega Ohm) through SPI interface into MCU. Can anyone help me to find the right SPI IC usable? I considered the MCP41xxx but it says the largest ...
2
votes
2answers
110 views

Unpowered devices on I2C/SPI bus

I'm trying to develop a board that includes I2C and SPI devices that are unpowered for the majority of the time to save power. I found that for these particular devices (Honeywell HSC pressure ...
1
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2answers
58 views

AVR reprogramming in circuit wirelessly

What are my options when it comes to reprogramming an AVR in-circuit? The new program will be received via a wireless connection, so it will need to be stored in some temporary memory container. I ...
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0answers
82 views

Can't read the SPI buffer of a PIC32MX

I have some problems with my SPI communication. Indeed, I have configurated the PIC32 as master, and it communicates with a slave which is a memory. The communication works perfectly. LEGEND : In ...
4
votes
2answers
181 views

SPI Flash device selection using SCLK, MOSI as well as SS?

In a system with N SPI devices it would normally take N+3 pins on the master to communicate with them all (NxSS, SCLK, MOSI, MISO). With N being large and the master device (FPGA) is pin limited, I'm ...
0
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0answers
151 views

PIC16F767 as SPI Slave: Can't clock out data

I have a Raspberry Pi and a PIC16F767 connected via SPI. The rPi is the master, the PIC is the slave. I can write data to the PIC just fine and dandy, but I can't seem to get the PIC to clock data ...
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0answers
99 views

Few SPIs at the same time as a bus?

According to http://www.st.com/web/catalog/mmc/FM141/SC1169/SS1031/LN775/PF216846, All STM32F1xx-series MCUs (and up) "offer standard communication interfaces (up to two I2Cs, three SPIs, one HDMI ...
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0answers
61 views

Controlling a TLC5927 LED Driver

I am trying to control TLC5927, with no success. I have read the whole datasheet, but I still can't figure it out. I tried to simulate it, with no success too. Can someone draw me a timing diagram ...
1
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1answer
113 views

What is wrong with this SPI implementation

I designed a system with RaspberryPi and STM32F407's, communicating with each other via SPI interfaces. For the last 3 months, tests were OK but yesterday a RaspberryPi and 2 of STM32F407's SPI ...
3
votes
2answers
160 views

Will an SPI EEPROM chip have the same issues with non-atomic write operations as a dsPIC's internal EEPROM? [duplicate]

A while back I had some intermittent trouble with the internal EEPROM of a dsPIC. Every so often, some value in the EEPROM would be found zeroed out on power-on. I tracked the problem down to when the ...