mirror of
https://github.com/RobTillaart/Arduino.git
synced 2024-09-20 00:55:58 -04:00
259 lines
10 KiB
Markdown
259 lines
10 KiB
Markdown
|
|
[](https://github.com/marketplace/actions/arduino_ci)
|
|
[](https://github.com/RobTillaart/MCP23S17/actions/workflows/arduino-lint.yml)
|
|
[](https://github.com/RobTillaart/MCP23S17/actions/workflows/jsoncheck.yml)
|
|
[](https://github.com/RobTillaart/MCP23S17/issues)
|
|
|
|
[](https://github.com/RobTillaart/MCP23S17/blob/master/LICENSE)
|
|
[](https://github.com/RobTillaart/MCP23S17/releases)
|
|
[](https://registry.platformio.org/libraries/robtillaart/MCP23S17)
|
|
|
|
|
|
# MCP23S17
|
|
|
|
Arduino library for MCP23S17 16 channel SPI port expander.
|
|
|
|
|
|
## Description
|
|
|
|
This library gives easy control over the 16 pins of a (SPI) MCP23S17 chip.
|
|
|
|
This IC is strongly related to the MCP23017 I2C port expander - https://github.com/RobTillaart/MCP23017_RT
|
|
Programming Interface is kept the same as much as possible.
|
|
|
|
|
|
#### 0.4.0 Breaking change
|
|
|
|
The version 0.4.0 has breaking changes in the interface.
|
|
The rationale is that the programming environment of the **Arduino ESP32 S3**
|
|
board uses a remapping by means of the include file **io_pin_remap.h**.
|
|
This file remaps the pins of several core Arduino functions.
|
|
The remapping is implemented by #define macros and these implement "hard" text
|
|
replacements without considering context.
|
|
The effect is that methods from this class (and several others) which have the same
|
|
name as those Arduino core functions will be remapped into something not working.
|
|
|
|
The following library functions have been renamed:
|
|
|
|
| old name | new name | notes |
|
|
|:-----------------|:-------------|:--------|
|
|
| analogRead() | read() |
|
|
| analogWrite() | write() |
|
|
| pinMode() | pinMode1() |
|
|
| digitalRead() | read1() |
|
|
| digitalWrite() | write1() |
|
|
|
|
|
|
#### 0.3.0 Breaking change
|
|
|
|
The version 0.3.0 has breaking changes in the interface.
|
|
The essence is removal of ESP32 specific code from the library.
|
|
This makes it possible to support the ESP32-S3 and other processors in the future.
|
|
Also it makes the library a bit simpler to maintain.
|
|
|
|
|
|
#### Related
|
|
|
|
16 bit port expanders
|
|
|
|
- https://github.com/RobTillaart/MCP23017_RT
|
|
- https://github.com/RobTillaart/MCP23S17
|
|
- https://github.com/RobTillaart/PCF8575
|
|
|
|
|
|
8 bit port expanders
|
|
|
|
- https://github.com/RobTillaart/MCP23008
|
|
- https://github.com/RobTillaart/MCP23S08
|
|
- https://github.com/RobTillaart/PCF8574
|
|
|
|
|
|
## Interface
|
|
|
|
```cpp
|
|
#include "MCP23S17.h"
|
|
```
|
|
|
|
### Constructor
|
|
|
|
- **MCP23S17(uint8_t select, uint8_t dataIn, uint8_t dataOut, uint8_t clock, uint8_t address = 0x00)** constructor SOFTWARE SPI.
|
|
- **MCP23S17(uint8_t select, SPIClassRP2040\* spi)** constructor HARDWARE SPI with explicit SPI interface selected.
|
|
- **MCP23S17(uint8_t select, SPIClass\* spi)** constructor HARDWARE SPI with explicit SPI interface selected.
|
|
- **MCP23S17(uint8_t select, uint8_t address = 0x00, SPIClassRP2040\* spi = &SPI)** constructor HARDWARE SPI with optional address pins and SPI interface.
|
|
- **MCP23S17(uint8_t select, uint8_t address = 0x00, SPIClass\* spi = &SPI)** constructor HARDWARE SPI with optional address pins and SPI interface.
|
|
- **bool begin()** returns true if successful.
|
|
- **bool isConnected()** returns true if connected, false otherwise. (dummy for compatibility reasons)
|
|
- **uint8_t getAddress()** returns the address set in the constructor.
|
|
Default = 0, range = 0..7.
|
|
|
|
The two hardware constructors allow to call 4 different constructors.
|
|
|
|
```cpp
|
|
- MCP23S17(10); // select pin only
|
|
- MCP23S17(10, 7); // select pin + address pins
|
|
- MCP23S17(10, 7, &SPI2); // select pin + address pins + SPI port
|
|
- MCP23S17(10, &SPI2); // select pin + SPI port
|
|
```
|
|
|
|
|
|
#### Sharing SELECT lines
|
|
|
|
(verified in #19)
|
|
Technically two chips could use the same SELECT pin and a different address.
|
|
Since 0.2.5 the constructors allow to setup such a configuration.
|
|
The added value is that one can use up to 8 devices (= 128 IO lines) with only
|
|
four lines (MISO, MOSI, CLOCK, SELECT).
|
|
|
|
I assume that this configuration is less used and IMHO not recommended.
|
|
NB it is more difficult to detect which device is selected when debugging.
|
|
|
|
To use the hardware addresses the Hardware Address ENable register must be set.
|
|
See datasheet 3.3.2 ADDRESSING SPI DEVICES, need to set IOCON.HAEN.
|
|
|
|
The library supports two ways:
|
|
```cpp
|
|
MCP.enableControlRegister(MCP23S17_IOCR_HAEN); // or 0x08
|
|
or
|
|
MCP.enableHardwareAddress(); // 0.2.5 version and up
|
|
```
|
|
|
|
See also **IO Control Register** section below.
|
|
|
|
|
|
### Single pin interface
|
|
|
|
- **bool pinMode1(uint8_t pin, uint8_t mode)** pin = 0..15, mode = INPUT, OUTPUT. Returns true if successful.
|
|
- **bool write1(uint8_t pin, uint8_t value)** pin = 0..15, value = LOW(0) HIGH (!0). Returns true if successful.
|
|
- **uint8_t read1(uint8_t pin)** pin = 0..15, returns LOW or HIGH, might set the lastError();
|
|
- **bool setPolarity(uint8_t pin, bool reversed)** pin = 0..15, set reversed flag. Returns true if successful.
|
|
- **bool getPolarity(uint8_t pin, bool &reversed)** pin = 0..15, reads reversed flag. Returns true if successful.
|
|
- **bool setPullup(uint8_t pin, bool pullup)** pin = 0..15, set pull-up flag. Returns true if successful.
|
|
- **bool getPullup(uint8_t pin, bool &pullup)** pin = 0..15, reads pull-up flag. Returns true if successful.
|
|
|
|
|
|
### 8 pins interface
|
|
|
|
- **bool pinMode8(uint8_t port, uint8_t value)** port = 0..1, value = 0..255. Returns true if successful.
|
|
- **bool write8(uint8_t port, uint8_t value)** port = 0..1, value = 0..255. Returns true if successful.
|
|
- **uint8_t read8(uint8_t port)** port = 0..1, reads 8 pins into one byte.
|
|
- **bool setPolarity8(uint8_t port, uint8_t mask)** port = 0..1, sets polarity for 8 channels at once.
|
|
Returns true if successful.
|
|
- **bool getPolarity8(uint8_t port, uint8_t &mask)** port = 0..1, reads polarity of 8 channels at once.
|
|
Returns true if successful.
|
|
- **bool setPullup8(uint8_t port, uint8_t mask)** port = 0..1, sets pull-up for 8 channels at once.
|
|
Returns true if successful.
|
|
- **bool getPullup8(uint8_t port, uint8_t &mask)** port = 0..1, reads pull-up for 8 channels at once.
|
|
Returns true if successful.
|
|
|
|
|
|
### 16 pins interface
|
|
|
|
- **bool pinMode16(uint16_t value)** value = 0..0xFFFF, returns true if successful.
|
|
Returns true if successful.
|
|
- **bool write16(uint16_t value)** value = 0..0xFFFF, returns true if successful.
|
|
Returns true if successful.
|
|
- **uint16_t read16()** reads 16 pins into an uint16_t.
|
|
- **bool setPolarity16(uint16_t mask)** sets polarity for 16 channels.
|
|
Returns true if successful.
|
|
- **bool getPolarity16(uint16_t &mask)** reads polarity of 16 channels.
|
|
Returns true if successful.
|
|
- **bool setPullup16(uint16_t mask)** sets pull-up for 16 channels.
|
|
Returns true if successful.
|
|
- **bool getPullup16(uint16_t &mask)** reads pull-up for 16 channels.
|
|
Returns true if successful.
|
|
|
|
Since 0.2.6 the reading and writing to registers have been performance optimized for the 16 bit interface.
|
|
If there are problems please open an issue.
|
|
|
|
|
|
### IO Control Register
|
|
|
|
Since 0.2.3 the library supports setting bit fields in the IO control register.
|
|
Read the datasheet carefully!
|
|
|
|
- **void enableControlRegister(uint8_t mask)**
|
|
- **void disableControlRegister(uint8_t mask)**
|
|
|
|
|
|
| constant | mask | description |
|
|
|:-----------------------|:------:|:--------------|
|
|
| MCP23S17_IOCR_BANK | 0x80 | Controls how the registers are addressed.
|
|
| MCP23S17_IOCR_MIRROR | 0x40 | INT Pins Mirror bit.
|
|
| MCP23S17_IOCR_SEQOP | 0x20 | Sequential Operation mode bit.
|
|
| MCP23S17_IOCR_DISSLW | 0x10 | Slew Rate control bit for SDA output.
|
|
| MCP23S17_IOCR_HAEN | 0x08 | Hardware Address Enable bit (MCP23S17 only).
|
|
| MCP23S17_IOCR_ODR | 0x04 | Configures the INT pin as an open-drain output.
|
|
| MCP23S17_IOCR_INTPOL | 0x02 | This bit sets the polarity of the INT output pin.
|
|
| MCP23S17_IOCR_NI | 0x01 | Not implemented.
|
|
|
|
|
|
Two dedicated functions are added since 0.2.5.
|
|
|
|
- **void enableHardwareAddress()** set IOCR_HAEN bit.
|
|
- **void disableHardwareAddress()** clear IOCR_HAEN bit.
|
|
|
|
|
|
### Error codes
|
|
|
|
If one of the above functions return false, there might be an error.
|
|
|
|
- **int lastError()** Above functions set an error flag that can be read with this function.
|
|
Reading it will reset the flag to **MCP23S17_OK**.
|
|
|
|
| name | value | description |
|
|
|:--------------------------|:-------:|:--------------|
|
|
| MCP23S17_OK | 0x00 | No error |
|
|
| MCP23S17_PIN_ERROR | 0x81 |
|
|
| MCP23S17_I2C_ERROR | 0x82 | (compatibility)
|
|
| MCP23S17_VALUE_ERROR | 0x83 |
|
|
| MCP23S17_PORT_ERROR | 0x84 |
|
|
| MCP23S17_REGISTER_ERROR | 0xFF | low level.
|
|
|
|
|
|
## Operation
|
|
|
|
See examples.
|
|
|
|
|
|
## Future
|
|
|
|
#### Must
|
|
|
|
- improve documentation
|
|
|
|
#### Should
|
|
|
|
- buy additional hardware
|
|
- keep functional in sync with MCP23017_RT
|
|
- test with multiple devices.
|
|
- multi SELECT lines
|
|
- add example with interrupts
|
|
- test
|
|
- IOCON.HAEN, Hardware Address ENable.
|
|
- should this be enabled in **begin()** by default? 0.3.0
|
|
- check address range in constructor.
|
|
|
|
#### Could
|
|
|
|
- check need for writing in all functions (Polarity / Pull-up)
|
|
- check if bit mask changes.
|
|
- what is performance gain vs footprint?
|
|
- investigate and reimplement the INPUT_PULLUP for pinMode() ?
|
|
- RP2040 support for SPI, setGPIOpins() etc
|
|
- See MCP_DAC
|
|
- AVR software SPI optimize
|
|
- dao and clock - see fastShiftOut.
|
|
|
|
#### Wont
|
|
|
|
|
|
## Support
|
|
|
|
If you appreciate my libraries, you can support the development and maintenance.
|
|
Improve the quality of the libraries by providing issues and Pull Requests, or
|
|
donate through PayPal or GitHub sponsors.
|
|
|
|
Thank you,
|
|
|
|
|