Page 126 - Toucpad robotics C11

Uses in Robotics
Sensor Integration: Very popular for connecting multiple sensors (like accelerometers, gyroscopes, magnetometers,
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pressure sensors, temperature sensors) to a single microcontroller, reducing wiring complexity.
Real-time Clocks and Memory: Interfacing with Real-time Clock (RTC) modules or Electrically Erasable Programmable
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Read-Only Memory (EEPROM) chips for data storage.
Small Displays: Controlling small Liquid Crystal Displays (LCDs) or Organic Light Emitting Diode (OLED) displays.
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Motor Driver Control: Some motor drivers can be controlled via I2C for setting speed or direction.
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Speed and Performance

Moderate Speed: Faster than UART but generally slower than SPI. Standard speeds range from 100 kilobits per
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second (kbps) (Standard Mode) to 400 kbps (Fast Mode), with faster modes like 1 Megabit per second (Mbps)
(Fast Mode Plus) and 3.4 Mbps (High-Speed Mode) available.
Overhead: The addressing and acknowledgement overhead can reduce the effective data throughput.
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Error Detection and Reliability
Acknowledgement Bit: The acknowledgement mechanism provides a basic form of error detection, confirming if a
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byte was received.
No Cyclic Redundancy Check (CRC): Does not include more robust error detection like a Cyclic Redundancy Check,
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meaning some data corruption might go undetected.
Bus Arbitration: In multi-master systems, a mechanism called “arbitration” ensures that only one master transmits
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at a time, preventing data collisions.
Reliability: Generally reliable for short-distance communication within a circuit board or between closely located
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components.

Serial Peripheral Interface (SPI)
Description
Serial Peripheral Interface, often called SPI, is a synchronous serial communication protocol primarily used for high-speed
data transfer over short distances, typically between a microcontroller (master) and one or more peripheral devices
(slaves).

Key Characteristics and Differences
Synchronous: Uses a shared clock line for synchronization.
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Four Wires: Typically uses four dedicated wires, allowing full-duplex communication:
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∑ Master Out Slave In (MOSI): Data from master to slave.
∑ Master In Slave Out (MISO): Data from slave to master.
∑ Serial Clock (SCK or SCLK): Clock signal generated by the master.

∑ Slave Select (SS or CS - Chip Select): A separate line for each slave. The master pulls this line low to enable
(select) a specific slave it wants to communicate with.

Master-Slave Architecture: One master device controls communication with one or more slave devices. Each slave
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requires its own dedicated Slave Select line.
Full-Duplex: Allows simultaneous bidirectional communication (sending and receiving data at the same time).
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No Addressing: Unlike I2C, SPI does not use device addresses. Instead, the master selects a slave by activating its
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dedicated Slave Select line.
Continuous Data Streaming: Can send continuous streams of data without needing start/stop conditions for each
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byte, making it very efficient for large data transfers.

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Touchpad Robotics - XI