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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28 views

Is Quad SPI the same thing as SQI?

Simple question (hopefully): Is QSPI the same thing as SQI ? FYI: I saw this topic What is dual/quad I/O? but I am still not sure, however I would rather say it is the same. EDIT: In particular I ...
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1answer
32 views

What would I expect to read from a disconnected SPI port?

I'm writing a program that reads from a SPI port. However, there's some complicated logic that controls whether the slave is physically connected to the port (if not, the lines are left floating). ...
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1answer
28 views

level translator IC for SPI [on hold]

In my current project I am working on the scheme and need a IC with following requirements: - It has to be a lever translator from 2.2V to 3.3V; - It has 5 channels; - on 2.2V side It has 3 ...
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1answer
33 views

ADXL345 GY-291 weird measures

currently I am trying to connect several ADXL345 to an Arduino Nano. I followed the Sparkfun Tutorial on how to do this (https://www.sparkfun.com/tutorials/240). Long story short, I connected two ...
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1answer
100 views

SPI data storage devices: (micro)SD card, DataFlash, or serial EEPROM?

I am revisiting some of my design habits, and one of them is under serious scrutiny: the go-to SPI-based storage device is (micro)SD cards, for their price-to-capacity ratio and generally higher ...
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1answer
30 views

Which side of SPI link harness to locate SDO pull-up?

I'm looking for some help/insight into a decision I am making about whether to change a circuit I have built. My slave device requires a pull-up on its SDO (MISO) pin which is open collector. When ...
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2answers
83 views

USB, UART, SPI difference and usage? [closed]

I am trying to enabling an embedded system built around Intel D1000 MCU. I am mainly from a software background and just starting to catch up with some hardware knowledge. I am trying to build ...
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1answer
58 views

SPI Master: High impedance on MOSI?

I'm interfacing the Nordic nRF52 chip with an FPGA, and sometimes I need MOSI to be at a high impedance state (read "Z" in VHDL). Else the slave won't acknowledge that the data has been transferred ...
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2answers
63 views

SPI bus – how to route two Slave Select lines to the same slave

We have legacy system of four boards: one containing chip acting as SPI master, three others containing chips acting as SPI slaves. My goal is to eliminate two of the slave boards; however, the ...
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1answer
151 views

SPI transaction between FPGA and Microcontroller

I'm trying to write a communication protocol between an FPGA and a Microcontroller through an SPI, the µC being the Master here. FPGA: Lattice iCE40 Ultra Breakout Board Rev.A (iCE5LP4K) µC : ...
2
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0answers
26 views

MCP4131: How to know what value resistors to use on the multiplexed SPI IO?

There are two aspects here. The first question is related to R1 below: The datasheet says: "R1 must be sized to ensure VIL and VIH of the devices are met" but gives no formula. So first question: (...
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2answers
173 views

What is the difference between “normal read” and “fast read” in the flash A25L032

The Flash A25L032 has a normal read mode and a fast read mode. It also has dual and quad read modes that are self-explanatory. However, the difference between the normal and fast modes is not at all ...
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1answer
39 views

SPI with multiple slaves working on different voltages

Is there any way to hook up two slave devices in SPI mode: one working on 3.3V and another on 5V level, using a micro controller without using a logic level converter to interface between them? ...
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3answers
98 views

Getting a more stable signal on very long strips of adressable RGB LEDs

I need to drive a 12m strip of APA102 RGB LEDs (144 per meter). I use a Raspberry Pi for this Job. This LED driver IC (APA102) takes an SPI signal and hands it to the next LED in the series and so on....
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2answers
102 views

16 separate lines via USB

So let me start apologizing if the question doesn't make any sense at all, I'm a total noob and I haven't quite grasped most of the concepts yet. I have designed this small visual indicator, which ...
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2answers
59 views

Why are all the slave select lines are high on a SC18IS602B chip?

The SC18IS602B chip is an I2C slave device that bridges to a number of SPI devices. I'm using this to talk to 3 SPI devices that use TLC5925 constant current LED sink drivers. These devices are known ...
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0answers
54 views

SPI interface with MAXIM ADC chips

I'm working specifically with MAX1257 but according to the spec sheets the behavior is consistent across the whole lineup of their I/O extender chips. Here's excerpt from the spec: The MAX1220/...
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1answer
42 views

STM32F107 SPI -> UART maximal transfer rate

I am designing a board with STM32F107 microcontroller and AD7680 ADC. What I need is to read data from ADC, increment sequence number after reading each sample, and send ADC values via UART or USB OTG ...
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5answers
231 views

Why don't on board communications like I2C, SPI, etc. have error checking in general?

Some error checking methods like parity check, checksum, CRC, etc. are used for wired/wireless communications. However, most of the ICs with interfaces like I2C, SPI, etc. don't use an error checking ...
2
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0answers
51 views

PIC32MX350F256 Errata , IO open Drain Issue

In one of our Product we used Microchip micro controller “ PIC32MX350F256L”. Attached image is small part of circuit showing uC interfacing with a SPI device. We are using bit banging communication ...
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2answers
106 views

Isolate microcontroller from board and use other one

The attached circuit block diagram shown in the rectangular box is my development board. It has microcontroller 1, which communicates with a SPI slave device (4 SPI line + 3 IO). 3.3V power goes to ...
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1answer
55 views

How to interface Si8902 with ATmega128rfa1?

The ATtmega128rfa1 works as master and Si8902 works as slave that is okay. But when a request is given Si8902 takes 8us to reply back with the ADC data. How can master wait for 8 us. How to ...
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1answer
125 views

Wrong signal on MISO line

I am trying to setup communication between my MCU and slave chip but here are the results from logic analyzer: I have basic knowledge of SPI protocol but as far as I know, data should be sampled at ...
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1answer
37 views

Can I use ATtiny SPI and still be able to do in-system programming?

I'm building a cost sensitive device that requires SPI and a single analogue comparator. Looking at the spec, ATtiny20 or ATtiny48 would fit the bill. The requirement is to be able to program it in ...
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1answer
100 views

STM32 HAL SPI Remap Single Pin

I would like to know if it is possible to remap a single pin of a multi-pin (SPI) peripheral? For instance, I have a STM32F107 and I want to use UART4, SPI3 and Ethernet. PC10 = UART4_TX - Remap ...
3
votes
1answer
88 views

SPI bus termination and pull-up resistors

My microcontroller (ATMEL series) needs to communicate to a slave device using SPI protocol. I am designing the hardware. The maximum SPI bus speed is 1 MHz. The distance between the master and slave ...
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1answer
46 views

Differences & Similarities between I2C & SPI Analyzers [closed]

I am learning about I2C and SPI analyzers and want to know about the differences between the two. What is the difference between their functionality and what are the similarities in these analyzers, ...
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1answer
52 views

Can I use external clock as SCK in master mode (dspic33e)?

I am using a dspic33ep512mc806 and I want to use two different SPI modules with the same clock (not only at the same frequency but one clock shared by both modules) and both modules have to be master ...
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1answer
21 views

AVRISP. How to choose SPI frequency?

Yes, yes, I know that it must be between 1 and 4 clock cycles of a target device. But... We don't know it if clock is provided by internal rc generator or external quartz. So is there any possible way ...
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0answers
56 views

STM8S - Connect to ADXL345 Acceleration Sensor via Hardware SPI

After software SPI didn't work out i now try to connect to the ADXL345 acceleration sensor via hardware SPI of the STM8S103F3. But, of course, problems appeared again, why not. This is my SPI-Init ...
0
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1answer
49 views

SPI Half-Duplex for the Holtic HI-3593 ARINC429 IC

I am having some problem understanding half duplex SPI. My understanding of SPI is when you send a byte you read the garbage byte, and if you want to read a value you send a dummy byte to read the ...
0
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1answer
52 views

Multiple SPI devices with different logic levels

I'm going to use one of the PIC32MX795F512L SPI peripherals (master), 1 to 4MHz, to communicate with multiple devices (slaves): Wi-Fi module MRF24WG0MA (3.3V); uSD card (3.3V); 9 modules with ...
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0answers
56 views

ESP822 and high speed external ADC

I'm playing with ultrasound signals, and with ultrasound images. Data was acquired using either a Redpitaya board or a bitscope micro. Now, I'm trying to sample my signal at ~2Msps, through bursts: I'...
0
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1answer
62 views

Atmel SPI Serial EEPROM Writing Error - Page Write?

I'm using this EEPROM: Atmel AT25640B SPI EEPROM DATASHEET It seems pretty straight forward to operate and I've followed the datasheet closely when coding my driver. I seemed to have some success ...
3
votes
1answer
75 views

SPI: How does communication work with a device that has multiplexed SDO and SDI signals?

Yes this question is related to MCP4131 which is a 8 pin digital potentiometer. I have never seen/heard/used multiplexed SPI before so am trying to clear some confusions. The datasheet shows ...
2
votes
1answer
65 views

SPI to Numerous Chips on Different PCBs with FFC Cables?

I want to drive numerous chips on several different PCBs with SPI from a microcontroller over FFC cables. Here is a crude diagram: UPDATE: Green wires are ground scheme I have never attempted such ...
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2answers
100 views

ADXL345 acceleration data readout looks strange - STM8

after finally finding out how to create a software SPI connection i now can successfully read the data from an ADXL345 acceleration sensor. But they look rather strange to me, this are some sample ...
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1answer
81 views

Not enough digital outputs for SPI slave select lines (CS#)

I have a microcontroller with only 4 digital outputs available and 4 digital inputs. The problem is that I need to communicate with at least 4 SPI devices (ADC's and DAC's). 4 SPI devices means 2 ...
0
votes
2answers
45 views

How to Minimally Communicate with an ADS131E04 ADC via SPI

I have bought a few ADCs from http://www.ti.com/product/ADS131E04 and I cannot get hear from them via the SPI. I am putting the ADC in a TQFP socket and I connect the PWDN, RESET, SCLK, CS, DIN, and ...
7
votes
3answers
360 views

SPI bus connections - to loop or not to loop?

I have a question regarding the physical connection of an SPI bus. I have an SPI master (a PIC32 device) and a number of slaves (in this case PIC16 devices). I'm only writing to the slaves, and the ...
0
votes
2answers
135 views

STM32F411 SPI slave enters debug infinite loop

I've connected two NUCLEOSTM32F411RE together, and trying to send an ASCII letter from one PC to another PC in Simplex mode from master to slave. When I send a character the slave enters a routine in ...
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1answer
43 views

Since SPI contains data and clock, this makes it “source synchronous” doesn't it?

I read in a Xilinx application note that as data rates became faster became developed source synchronous transfer technique and later came the self-synchronous methods that make use of 8b-10b or some ...
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1answer
78 views

Software SPI 3-wire read register

I currently try to read a register from an acceleration sensor (ADXL345). i try to simulate the SPI procedure with software. I wrote a readRegister function: ...
1
vote
3answers
147 views

SPI between MCUs

As a newcomer to PIC programming, I am looking for some thoughts on how to implement SPI between a master and slave MCU the most efficient way. The purpose of this system is to provide an extremely ...
1
vote
1answer
131 views

Why can I read accelerometer and gyroscope data on the LSM9DS1 with SPI, but not the magnetometer data on the same device?

I'm currently working on a device that uses the LSM9DS1, a 9-axis motion sensor by ST Microelectronics. I’m using a PIC24FJ128GB202 microcontroller by Microchip, and communicating with the sensor ...
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0answers
38 views

Bus Pirate binary protocol gets stuck in BBIO mode (or an invalid state) after a bulk transfer operation

I have a v.3a (SFE) Bus Pirate with v6.1 firmware, and am trying to make it talk binary SPI mode (to an AT89LP51, btw). Things start off OK, until I try to perform a bulk transfer operation (using ...
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0answers
46 views

VHDL - loop counter bug with SPI protocol

I want to write a simple reader from SPI data, to read 1 byte and transfer it to another block. I used the following code : ...
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2answers
68 views

Serial Peripheral Interface - multi slave question

When implementing SPI communication between a master and multiple slaves, there's basically two topologies to choose from: either resend the same data to each slave, or clocking data through all ...
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0answers
43 views

Maximum SPI clock frequency of CP2130 USB-SPI bridge

I have a board with SMT32F103 MCU and CP2130 chip connected to MCU's SPI2 channel. CP2130 is master only, so I configure MCU's SPI to act as a slave with software slave management. There are no more ...
0
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1answer
50 views

SPI refuses to send in dspic33

I'm trying to talk to an RFM22 wireless module. I'm having a hard time getting the SPI functional. I'm working with a dspic33ep512mc806. I'm debugging directly in hardware with a pickit3. After ...