The MCP23S17-E/SS is a component from Microchip Technology, which is a well-known manufacturer of microcontrollers, analog semiconductors, and other digital components.
MCP23S17-E/SS Overview:
Type: I/O Expander (Serial) Package: SSOP (Small Shrink Outline Package) Pin Count: 28 pinsThis device is an I/O expander with a serial interface , allowing the extension of I/O pins to microcontrollers or other systems over SPI communication. It has a 16-bit I/O expander with internal registers for controlling the inputs and outputs.
Pin Function Specification and Circuit Principle
Pinout of MCP23S17-E/SS (28 Pins) Pin No. Pin Name Function Description 1 VSS Ground. Connect to the system ground. 2 VDD Power supply. Connect to the positive voltage (2.0V to 5.5V). 3 SDA (SDI) Serial Data Input. Used for data transfer in SPI mode. 4 SCL (SCK) Serial Clock Input. The clock signal to synchronize data transfer in SPI mode. 5 A0 Address Pin 0. Used to select the I2C address when using I2C communication. 6 A1 Address Pin 1. Used to select the I2C address when using I2C communication. 7 A2 Address Pin 2. Used to select the I2C address when using I2C communication. 8 INTB Interrupt (active low). An interrupt pin which signals when any input change is detected. 9 RESET Reset Pin (Active low). When low, the device is reset. 10 GP0 GPIO Pin 0. General Purpose Input/Output pin. Can be configured as input or output. 11 GP1 GPIO Pin 1. General Purpose Input/Output pin. Can be configured as input or output. 12 GP2 GPIO Pin 2. General Purpose Input/Output pin. Can be configured as input or output. 13 GP3 GPIO Pin 3. General Purpose Input/Output pin. Can be configured as input or output. 14 GP4 GPIO Pin 4. General Purpose Input/Output pin. Can be configured as input or output. 15 GP5 GPIO Pin 5. General Purpose Input/Output pin. Can be configured as input or output. 16 GP6 GPIO Pin 6. General Purpose Input/Output pin. Can be configured as input or output. 17 GP7 GPIO Pin 7. General Purpose Input/Output pin. Can be configured as input or output. 18 GP8 GPIO Pin 8. General Purpose Input/Output pin. Can be configured as input or output. 19 GP9 GPIO Pin 9. General Purpose Input/Output pin. Can be configured as input or output. 20 GP10 GPIO Pin 10. General Purpose Input/Output pin. Can be configured as input or output. 21 GP11 GPIO Pin 11. General Purpose Input/Output pin. Can be configured as input or output. 22 GP12 GPIO Pin 12. General Purpose Input/Output pin. Can be configured as input or output. 23 GP13 GPIO Pin 13. General Purpose Input/Output pin. Can be configured as input or output. 24 GP14 GPIO Pin 14. General Purpose Input/Output pin. Can be configured as input or output. 25 GP15 GPIO Pin 15. General Purpose Input/Output pin. Can be configured as input or output. 26 RW Read/Write Mode. Used to define whether the device is in read or write mode. 27 SDO (SDO) Serial Data Output. Used for SPI interface for data transfer. 28 NC No Connect. This pin is not connected to any internal circuitry. Can be left floating.FAQs (20 Common Questions about MCP23S17-E/SS)
1. Q: What is the MCP23S17-E/SS device used for?A: The MCP23S17-E/SS is used as an I/O expander with a serial interface to increase the number of input/output pins for a microcontroller via SPI communication.
2. Q: What is the voltage range for VDD in MCP23S17-E/SS?A: The VDD pin should be connected to a voltage range between 2.0V and 5.5V.
3. Q: How many GPIO pins does the MCP23S17-E/SS have?A: The MCP23S17-E/SS has 16 General Purpose Input/Output (GPIO) pins.
4. Q: How do you control the direction of the GPIO pins?A: The direction of the GPIO pins can be control LED through the I/O direction registers (IODIR).
5. Q: What are the communication modes available for MCP23S17-E/SS?A: The MCP23S17-E/SS supports SPI communication in both master and slave modes.
6. Q: What is the purpose of the RESET pin?A: The RESET pin is used to reset the device to its default state when held low.
7. Q: What is the function of the INTB pin?A: The INTB pin is an interrupt output that signals when an input pin changes state.
8. Q: How do you configure the MCP23S17-E/SS pins as inputs or outputs?A: The pins can be configured as inputs or outputs by writing to the IODIR register.
9. Q: Can MCP23S17-E/SS be used in I2C communication?A: Yes, the MCP23S17-E/SS can be used in I2C mode, but it requires proper configuration of the address pins (A0, A1, A2).
10. Q: How is the chip reset in case of a malfunction?A: A low pulse on the RESET pin resets the chip to its initial state.
11. Q: Can the GPIO pins of MCP23S17-E/SS be used as inputs and outputs simultaneously?A: No, each GPIO pin can either be an input or output at any given time, but not both simultaneously.
12. Q: What is the maximum operating frequency for the SPI clock (SCL)?A: The maximum operating frequency for the SPI clock (SCL) is 10 MHz.
13. Q: How many I/O expander devices can be connected in a chain using SPI?A: Multiple MCP23S17 devices can be connected in series, limited by the SPI device's address configuration.
14. Q: What type of package does MCP23S17-E/SS come in?A: The MCP23S17-E/SS comes in a 28-pin SSOP (Small Shrink Outline Package).
15. Q: What is the difference between the MCP23S17 and MCP23S18?A: The MCP23S17 supports up to 16 I/O pins, whereas the MCP23S18 supports up to 16 I/O pins with enhanced features like higher voltage tolerance.
16. Q: How do I configure the interrupt functionality?A: The interrupt functionality can be configured via the IOCON register and the GPIO pin settings.
17. Q: Is the MCP23S17-E/SS capable of handling 5V logic?A: Yes, the MCP23S17-E/SS is 5V tolerant on its I/O pins.
18. Q: Can the GPIO pins be used to drive LEDs?A: Yes, the GPIO pins can drive LEDs, but current-limiting resistors should be used to prevent damage.
19. Q: How do I read data from the MCP23S17-E/SS?A: Data can be read by accessing the GPIO registers via SPI.
20. Q: How is the interrupt pin used in MCP23S17-E/SS?A: The INTB pin signals when a change in any of the GPIO inputs occurs, providing an interrupt output to the host processor.
This detailed information ensures all pin functions are covered, providing a complete understanding of the MCP23S17-E/SS.