11 votes
Accepted

Bit waveform clarification

To me it looks like ser.write(1) has an implicit conversion to string. So your 1 becomes a "1" which is 00110001, which perfectly fits into your observation.
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  • 2,632
6 votes

Inconsistency in continuous data acquisition on RPi

Cursory look over your code makes me think there might be a performance problem with the way you have interspersed your file writing logic with your acquisition loop. I am referring the fprintf ...
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3 votes
Accepted

Bit-banging with Python

1) Bit banging just means using software rather than hardware to implement a communications protocol. To bit bang I2C this means to control the SDA and SCL signals in software. SDA is connected to ...
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  • 67.2k
3 votes

Theoretical maximum data rate of GPIO pins

You can toggle a gpio at around 25 MHz. I expect you could get perhaps a tenth of that if you were to bit bang. Of course that really depends on what you are bit banging. For general information ...
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3 votes
Accepted

High speed bit bang GPIO reading

I do not remember why the limit is 250k rather than say 500k or 1000k. I expect there was a reason. It may simply have been there was too much jitter at the higher bit rates to reliably clock the ...
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2 votes
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Proper way to bit bang I2C

That LDAC signal is truly nasty. I have read the datasheet and your messages a few times and I can't quite focus on a specific issue so I figure out you're just brainstorming. I will start from what ...
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  • 319
2 votes

Proper way to bit bang I2C

A few thoughts: Using dedicated I2C pins for your bit-banged I2C should be fine as long as you don't use smbus at the same time. Improving GPIO timing in userspace can be done by increasing process ...
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2 votes

Using bypass capacitors to reduce voltage spikes and noise causing I2C read/write errors

Question I2C device reading writing errors problem. How to solve it? Answer There are many reasons causing reading and writing errors. To name a few: Wires too long (more than 30cm) and not ...
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2 votes
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Using bypass capacitors to reduce voltage spikes and noise causing I2C read/write errors

The solution is to bridge the RPi GND and 3v using a cap. I used a 1uF cap.
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  • 361
2 votes
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How to read RHT03 sensor

UmaN the sparkfun product description says "RHT03 (also known by DHT-22)" So finding the information you require should be much easier. Driver adafruit's github repo Has the "driver" written in ...
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1 vote
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Deinitialize GPIO access on I2C channels

Yes, set the GPIO back into mode ALT0 (needed by GPIO 2/3 to be in I2C mode). Tiny GPIO has the following define to use to set that mode. #define PI_ALT0 4
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1 vote

Bitbang I²C to multiple slaves with same address

I have never heard of this approach on the Pi. If clock stretching is not a issue I don't see why it could not work. I suggest you look at extending an I2C sniffer I wrote to test the idea. http://...
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1 vote

How many i2c buses?

What do you mean by at once? You can buy two TCA9548A I2C multiplexors which will allow you to connect 16 MPU6050 on the same bus (at the same bus address). However only one MPU6050 may be addressed ...
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1 vote

How to read RHT03 sensor

That appears to be a DHT22 sensor using a different brand name. Try my http://abyz.me.uk/rpi/pigpio/examples.html#pdif2_DHTXXD software.
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1 vote

Inconsistency in continuous data acquisition on RPi

Using DMA bit banging it is possible to get accurately timed gap-less samples from the MCP3202. The same technique should work for the MCP3201 with the obvious change to the SPI command to request ...
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1 vote

Inconsistency in continuous data acquisition on RPi

the data acquired has unaccounted gaps in it I think "accounting" for them is simple enough, it is arbitrary latency. If the units there are seconds, then that is a cause for consternation. If ...
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  • 56k
1 vote

Using INT interrupt line on PCF8574 I2C 8-bit IO-expander on Bit-banged RPi GPIO?

I have a very similar scenario as you: A distributed domotic system all over the house with a central device (Raspberry PI) and a few satellite boards with I2C (PCF8574/PCF8591) and 1-Wire (DS18B20). ...
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1 vote

I2C repeated start with BitBanging not working - Pigpio library on Raspberry Pi B+

Are you sure that you have the right value for RGB_ADDR? Whenever I have seen a -82 error with pigpio it has been because the I2C chip is not responding. This is usually because you are using the ...
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  • 483
1 vote

How fast is GPIO+DMA? Multi I2S input

Just see this. Raspberry-Pi-DMA-Example https://github.com/Wallacoloo/Raspberry-Pi-DMA-Example
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  • 11
1 vote

Raspberry Pi on AVC-LAN / IEBus

The Raspberry Pi isn't really suited for this application. You'll need to use hardware timers and pin interrupts to do it right. To receive a message on the bus, each part of it must be acknowledged ...
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  • 101
1 vote
Accepted

Multiplexing 4-digit 7-segment display is flickering

If I understand correctly what you are trying to do then there is a simple software solution. The following Python code should update multiplexed 7-segment LCDs in a flicker free way. For testing ...
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