Transcript EE_446_ACC_PSoC_Presentation

Programmable System-on-Chip (PSoC)
General Overview
Embedded Architectures
EE446
Typical Microcontroller Purposes
• The purpose for uC’s is to interface
multiple types of hardware.
– Digital Input/Outputs:
• Switches
• Relays
• LEDs
– Digital Communications: I2C, SPI
– Analog Input/Outputs
Computer
uC
Thermal
Gyro
Acceleration
Example of Hardware Interfacing
Regular Microcontroller
Caveats
– What if you need more Analog Inputs?
– What if you need more Interrupts?
– Advanced projects: more PWMs needed?
• Use external circuitry
• Buy a larger microcontroller
What is a Programmable
System-on-Chip (PSoC)?
• A customizable microcontroller that
includes flexible analog and digital
logic blocks.
– Analog blocks:
• High-resolution inputs (up to 20-bit)
• 4 Digital-to-Analog Converters
– Digital logic blocks (UDBs):
• A wide mix of digital peripherals can be
implemented into a single chip.
– Up to 4 voltage domains
– Almost all pins can be flexible in terms
of being digital or analog.
What is a Programmable
System-on-Chip (PSoC)?
• PSoC-5
(Powered by ARM Core)
– Provides above features plus
ARM processor benefits:
• Up to 67Mhz
• Flash: Up to 256kb
• SRAM: Up to 65kb
– Up to 70 I/O pins
General Overview of
PSoC Features
API
Cypress PSoC IDE
Cypress PSoC IDE (Block Configuration)
PSoC Pin Routing
PSoC Main Program Code
ISR Flag
Main loop
ISR Flag
API’s for the PSoC Blocks
API’s for the PSoC Blocks
Top-level
UDB Block Diagram
Top-level
UDB Routing Diagram
Extensive Uses of UDBs
• Examples of possible hardware configurations on a
single (and largest) PSoC chip:
– 12 UARTs
or
– 28 PWMs
• For a normal microcontroller, this configuration is
impossible without resorting to additional external
hardware, such as:
– Daisy-chain or bus-connected peripherals:
• Microcontrollers
• I2C/SPI-connected hardware for UART, PWM, etc.
Extensive Uses of UDBs
Technology Mapping
Summary
Extensive Uses of UDBs
Technology Mapping
Summary
PSoC Top-Level Analog Routing Diagram
PSoC Analog
Routing
• Analog Local Bus
– 4 on left side, 4 on right side
– Connects to analog resource blocks only
– No access to GPIO’s
• Analog Global Bus
– Connects I/O to analog resource blocks on same side
– Connects to GPIO on their respective quadrant
– 8 routes on left side, 8 routes on right side
• Analog Mux Bus
– Connects the buses to the ‘outside’ world
– Can connect to all GPIO’s and all analog resource blocks
PSoC Die Quadrants Analog Routing
Global Bus
Detailed Analog Routing
Interrupts
Why have interrupts?
• An external event that needs immediate attention.
– An ‘emergency’ switch
– A long-running timer
• PSoC-5 supports 16 system interrupts and 32
from peripherals.
– Tail Chaining (Back-to-Back)
– Late Arrival
(Lower  Higher)
– Reprioritize Interrupts
• Same Priority?
– Fixed Function  DMA  UDB
Interrupts
• Some modules that are used needs immediate attention in real time.
Interrupt Vector Table
How Interrupts Work
Interrupt Setup and ISR
Tail Chaining Interrupts
Late Arrival Interrupts
Polling vs Interrupting
• Signals can happen too fast for the CPU to
read or process!
Example PSoC Project
Firmware Overview
I/O Communications
Inputs
From
Sensors
Outputs
To
Devices
Raw Sensor Data Collection
to the Host PC
• Digital:
– I2C used in Gyroscopes, Accelerometers,
Magnetometers (IMU), and Temperature Sensor
– UART from Sonar @ 9600bps (8N1)
• For this particular usage, very inefficient.
• Requires interrupts and additional code complexity.
• Very slow data updates.
• ADC Settings and Inputs:
– 14-bits @ 70,000 Samples Per Second (currently)
– Vcc = 5 Volt (Reference)
– Raw value range:
• 0v
• 0


5v
16384
PSoC Data Output
•
Raw ADC Values: 85 updates/sec over Serial UART @ 115200bps (8N1)
Servo
Position
Infrared
Gyro
X-Axis
Gyro
Y-Axis
Gyro
Z-Axis
Sonar
(analog)
Host PC
Application GUI