GY-63_MS5611/libraries/FastShiftInOut/README.md

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# FastShiftInOut

Arduino library for **AVR** optimized shiftInOut (simultaneously).

Related libraries
- https://github.com/RobTillaart/FastShiftIn
- https://github.com/RobTillaart/FastShiftOut
- https://github.com/RobTillaart/ShiftInSlow
- https://github.com/RobTillaart/ShiftOutSlow


## Description

FastShiftInOut is a class that can send and receive bytes simultaneously.
In that sense it mimics a SPI bus.

Experimental.


## Performance

performance of **write()**

|  version  |  UNO (us)  |  ESP32 (us)  |
|:---------:|-----------:|-------------:|
|   0.1.0   |   181.08   |     4.32     |
|   0.1.1   |    26.84   |     4.32     |
|   0.1.2   |    26.84   |   no data    |
|   0.1.3   |    25.52   |     4.32     |


## Interface

```cpp
#include "FastShiftInOut.h"
```

#### Functions

bitOrder = { LSBFIRST, MSBFIRST };

- **FastShiftInOut(uint8_t dataIn, uint8_t dataOut, uint8_t clockPin, uint8_t bitOrder = LSBFIRST)** Constructor.
- **uint8_t write(uint8_t data)** reads and writes simultaneously.
- **uint8_t lastWritten(void)** returns last byte written.
- **uint8_t lastRead(void)** returns last byte read.
- **bool setBitOrder(uint8_t bitOrder)** bitOrder must be LSBFIRST or MSBFIRST.
- **uint8_t getBitOrder(void)** idem.
- **uint8_t writeLSBFIRST(uint8_t data)** optimized version, in practice almost no difference.
- **uint8_t writeMSBFIRST(uint8_t data)** optimized version, in practice almost no difference.


## Future

#### Must

- documentation
- follow FastShiftIn and FastShiftOut

#### should


#### could

- **void ignoreRead()**
- add Print interface?