Tagged Questions

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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35 views

SPI LCD Screen on OpenWrt based hardware using Atheros AR9331

I'd like to connect a graphics lcd 240x64px to my OpenWrt based hardware, which is based on Atheros AR9331 MIPS architecture. The development board I'm using has SPI outputs... I've been using the ...
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34 views

Off board SPI communication over 2 meter Lenght Bus

I have few queries on my SPI interface application. Specifications: Sensor: LDC1000. Data Out: Over SPI bus, f = 4MHz. SPI Bus Length = 2 meters. Raising edge= Data out, Falling edge= Data In. I want ...
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41 views

AVR SPI slower than expected

I'm running an ATMega88A at 8MHz and have the SPI configured to run at Fosc/2 = 4MHz. In theory, shifting out 5000 bytes over SPI should take 1/4000000 * 8 * 5000 = 10ms. But according to the ...
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24 views

Can't drive adafruit display with Arduino DUE

I'm currently trying to write a library for the Adafruit ST7565 graphic display. (see links below) The current one is entirely AVR specific and the code is generally pretty unreadable given the ...
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1answer
25 views

AVR SPI2X has no effect

I've got an ATMega88A configured to run on internal 8MHz clock: lfuse = 0xE2 hfuse = 0xDF efuse = 0x01 F_CPU defined as 8000000 This in confirmed in the 'real ...
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3answers
163 views

AVR SRAM limitation

I'm just an enthusiast looking for some advice. I'd like to use a microcontroller to read frames from a camera and write those frames to a small LCD screen. The camera and screen are on the same SPI ...
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41 views

Programming Slave SPI on PIC16LF1503 without SS pin

I'm tring to setup a SPI communication. I need to do this without SS pin usage, using only two device: one master and one slave. Now I'm able to send a byte correctly, I see it from a scope, but I ...
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2answers
183 views

Communication between micro controllers - I2C, SPI, UART?

Basically I have two microcontrollers that I need to communicate with each other. Both controllers send and receive data. Basic idea that I have: I2C, SPI - What I think we can NOT use these ...
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1answer
48 views

SPI reading from slave

I have small question about how bytes move around during SPI reading. I have a flash memory chip and microcontroller. Suppose I want to know jedec data from the chip(although it can be any data, this ...
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2answers
49 views

Raspberry Pi and TLC5615 DAC

Currently I'm working in a project in which I need to programmatically control 2 currents from 0 to 1 Amp. My plan is to use two DACs controlled by a Raspberry Pi. My idea was to use the MCP4725 but ...
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2answers
73 views

Multiple out signals with single clock

Here is the deal.. I need to transmit data to 8 identical components. Each component has a clock and an input signal. MCU only sends data. Components only receive data. All 8 components are the ...
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1answer
71 views

SD Card Access Library

I am accessing my SD card using SPI. But I've found this to be slow and I am also sad that when there is a faster protocol already supported by my SD card I am using a slower version. Is there a C ...
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1answer
94 views

SPI not working, ATmega328 only sending 1 byte

I am trying to get SPI working on an ATmega328. This is my code: ...
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0answers
71 views

How long of a wire and how big of a load can I have for SPI bus?

I have a system where I will connect up to 128 identical magnometer ICs up to an FPGA. I am trying to decide between SPI and I2C for comms. If I use SPI the setup will require 128 + 3 wires IF all ...
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1answer
51 views

Cable for transmitting 4MHz 3V3 signal

I am building a device on breadboard where there are 2 ICs: a microcontroller and some auxillary IC, they should communicate via SPI with a 4 MHz clock. Because I don't have enough place on my ...
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53 views

Canon EF SPI data protocol and IS activation

I have been trying to find information about Canon EF data protocol between lens and body. So far I have seen examples how to control focus or aperture but I would like to know how IS is activated. Is ...
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2answers
192 views

Erratic ADC output

I'm using a 12 bit ADC (MAX1270), SRAM (23LC1024) and PIC18f4550 to measure temperature transient at the output of an RTD. The communication protocol is SPI. The voltage is sampled and sent to PIC, ...
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2answers
236 views

Porting SPI code from (Intel) Galileo to Edison - Arduino

I'm currently working to port some Arduino sketches from Intel Galileo that use SPI (using a prototype Arduino Breakout board). I haven't been able to get it to work so far - but I have used an ...
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2answers
95 views

Two different SPI modes in one microcontroller

I am interfacing two chips with SPI communication with atmega328. One chip uses SPI mode 0 and other one SPI mode 1. Is it advisable to toggle modes in micro each time interrupt request is received ...
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1answer
149 views

STM32 SPI half duplex (1-wire Bidirectional) problem

I'm trying to read 4 byte from a SPI-compatible slave (MAX31855) in 1-wire bidirectonal SPI half-duplex. Here is my code [SW Controlled SS] [SO->MOSI] ...
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1answer
29 views

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
64 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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0answers
75 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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0answers
64 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
77 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
103 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
109 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
67 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
124 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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0answers
50 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
47 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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0answers
77 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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0answers
40 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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0answers
100 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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0answers
35 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
72 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
163 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
98 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
42 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
52 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
112 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 ...
3
votes
2answers
80 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
76 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 ...
0
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1answer
61 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
41 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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0answers
117 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
95 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
181 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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0answers
49 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 ...
0
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1answer
121 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 ...