Tagged Questions

-4
votes
1answer
35 views

How much max distance of SPI & USB & I2C and TWI(without any IC [closed]

How much max distance of SPI & USB & I2C and TWI(without any IC(my mean is directly)), and how can i amplify these?
2
votes
1answer
60 views

should I use 2 SPI devices on Arduino UNO/PRO or 2 I2C devices?

I am using a microSD breakout board and the accelerometer ADXL345 https://www.sparkfun.com/products/9836. each one alone works perfectly fine, but once I put both (sharing pins 11,12,13, but with ...
2
votes
1answer
69 views

What are some good older devices that I can scrounge i2c or spi modules from?

I am a newcomer to electronics design and I'd really like to start fiddling with making my own circuits. I have a raspberry pi which has both I2C and SPI interfaces, and I'm wondering if there's any ...
4
votes
2answers
108 views

How to deal with multiple pull-up resistors on modules

I was thinking about doing a modules for a development board I did a few days ago that will include spi/i2c interfaces. The problem is that I didn't included pull-up resistors in the MCU pins in the ...
1
vote
3answers
88 views

Use 74LCX245 level transeiver for SPI / I2C

I'm needing to convert the levels of the SPI and I2C busses of a 5v microntroller to a 3.3v card reader and epprom memory so I choosed to use the 74LCX245 since its a bidirectional transeiver. But ...
4
votes
0answers
101 views

Help to identify unknown Sync Serial Bus

Does somebody already seen a sync serial bus communication like that ? Repeated Pattern : Detail of beginning : I fail to identify it... it look like I2C but : it have a clock at 2MHz (so ...
0
votes
0answers
52 views

Library for multi-master comunication of two ATTinys 261/461/861 I2C/SPI

I am building device with two ATTiny 461 connected by about 60 cm long cable. I need ATTinys to send/receive only few bytes once a time. Random time, random direction. I would like multi-master ...
2
votes
1answer
409 views

Best way to communicate Raspberry Pi and ATTiny13

What is best way to connect two or three microcontrollers, ATTiny13 to Raspberry-Pi and get master (Raspberry Pi) communication? Are there any ready libraries for ATTiny13 for SPI or I2C? Maybe some ...
2
votes
3answers
204 views

Generation of text on composite video

I'm building a homebrew computer. I want some way to get video out, preferably along the lines of 80x25 text. I'm not interested in framebuffer graphics. Does such a thing exist as a single-chip text ...
1
vote
3answers
358 views

Two wire vs. three wire serial interface for RTC

I'm looking to choose an RTC for a project I have in mind. I have the following options (linked to datasheet): DS1307 DS1302 The main difference seems to be the communication protocol. The DS1307 ...
1
vote
4answers
197 views

I2C and SPI ,if they share same connection , is there confilict or not

We have a product which uses PIC18F4520, and we used some devices like LCD driver and so on, that all use I2C bus to comunicate with the micro. But now we want to add a couple of AD5504, which is a ...
5
votes
1answer
419 views

LCD modules with I2C or SPI interface

I would like to add an LCD to my current design (a project that is to be produced in low volume, around 50 to 100 units). A small display size (around 8 or 16 characters) should be plenty since it is ...
0
votes
2answers
255 views

I2C Pulldown and Pullup…is it possible?

I am using a PIC18F2550 to control a H Bridge, and I am using several input signals, such as RS-232, I2C and Analog 0-5V to make the final PWM output for the H bridge. I have a problem with PCB space, ...
0
votes
1answer
81 views

Keep SPI/TWI master active?

I'm designing a data recorder application which uses an 8-bit AVR microcontroller. It uses the TWI and SPI interfaces with the microcontroller being the master. There is one SPI device, a microSD ...
6
votes
2answers
220 views

Designing my own Bus

This question is further to my previous question: Alternatives to SPI because of EMI. I am toying with the idea of designing my own communication bus. I would be grateful if someone could cast their ...
8
votes
1answer
500 views

BMA180 accelerometer. How does it manage to share pins between I2C and SPI?

BMA180 accelerometer can be either SPI slave or I2C slave. The pins for both buses are shared. ...
12
votes
5answers
9k views

tradeoffs when considering SPI or I2C?

What tradeoffs should I consider when deciding to use an SPI or I2C interface? This accelerometer/gyro breakout board is available in two models, one for each interface. Would either one be easier ...
11
votes
7answers
658 views

General protocol for data transfer from one system to another?

What is the general protocol to send information from one system to another? For example, let's say we have some information collected from microcontroller over a length of time that we want to send ...
8
votes
5answers
555 views

What is the most popular embedded serial bus? [closed]

I'm designing an embedded device that I would like to make interoperable with third party peripherals through a serial bus. Should I choose SPI, I²C, or some other bus? The peripherals will be ...
1
vote
3answers
663 views

I2C 7seg driver

Does anyone know of any good I2C 7segment display drivers. I swear a previous answer referenced a chip for this on chiphacker but I cannot find it. I would also be happy with SPI, but I I2C would ...
20
votes
10answers
4k views

SPI or I2C… which to use for a longish bus

I'm contemplating a project that would require several AVRs talking to each other over a bus. They'd be separated by as much as 6 feet. It seems like both I2C and SPI can let a series of micros ...
8
votes
4answers
1k views

How to reverse engineer I2C and SPI protocols?

If I have an unkown device which talk I2C or SPI how can I reverse engineer the protocol. Basically I am looking for something similar as snoop or tcpdump. For software Mac is preferred but can also ...