SBOS487B June   2009  – March 2020 PGA280

PRODUCTION DATA.  

  1. Features
  2. Applications
  3. Description
    1.     Device Images
      1.      Typical Application
  4. Revision History
  5. Pin Configuration and Functions
    1.     Pin Functions
  6. Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 Electrical Characteristics
    3. 6.3 Timing Requirements: Serial Interface
    4. 6.4 Typical Characteristics
  7. Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Functional Blocks
        1. 7.3.1.1 Input Switch Network
        2. 7.3.1.2 Input Amplifier, Gain Network, and Buffer
        3. 7.3.1.3 Current Buffer
        4. 7.3.1.4 Input Protection
        5. 7.3.1.5 EMI Susceptibility
        6. 7.3.1.6 Output Stage
        7. 7.3.1.7 Output Filter
        8. 7.3.1.8 Single-Ended Output
        9. 7.3.1.9 Error Detection
      2. 7.3.2 Error Indicators
        1. 7.3.2.1 Input Clamp Conduction (ICAerr)
        2. 7.3.2.2 Input Overvoltage (IOVerr)
        3. 7.3.2.3 Gain Network Overload (GAINerr)
        4. 7.3.2.4 Output Amplifier (OUTerr)
        5. 7.3.2.5 CheckSum Error (CRCerr)
    4. 7.4 Device Functional Modes
      1. 7.4.1 GPIO Operation Mode
        1. 7.4.1.1 CS Mode
    5. 7.5 Programming
      1. 7.5.1 SPI and Register Description
      2. 7.5.2 Command Structure and Register Overview
        1. 7.5.2.1 Command Byte
        2. 7.5.2.2 Extended CS
          1. 7.5.2.2.1 SPI Timing Diagrams (Read and Write)
          2. 7.5.2.2.2 GPIO Pin Reference
          3. 7.5.2.2.3 Checksum
      3. 7.5.3 GPIO Configuration
      4. 7.5.4 Buffer Timing
    6. 7.6 Register Map
      1. 7.6.1  Register 0: Gain and External MUX Address (address = 00h) [reset = 0000 0000b]
      2. 7.6.2  Register 1: Software Reset Register (address = 01h) [reset = 0000 0000b]
      3. 7.6.3  Register 2: SPI: MODE Selection to GPIO-Pin (address = 02h) [reset = 0000 0000b]
      4. 7.6.4  Register 3: BUF Timeout Register (address = 03h) [reset = 0001 1001b]
      5. 7.6.5  Register 4: Error Register (address = 04h) [reset = 0000 0000b]
      6. 7.6.6  Register 5: GPIO Register (address = 05h) [reset = 0000 0000b]
      7. 7.6.7  Register 6: Input Switch Control Register 1 (address = 06h) [reset = 0110 0000b]
      8. 7.6.8  Register 7: Input Switch Control Register 2 (address =07h ) [reset = 0000 0000b]
      9. 7.6.9  Register 8: GPIO Configuration Register (address = 08h) [reset = 0000 0000b]
      10. 7.6.10 Register 9: CS Configuration Mode Register (address = 09h) [reset = 0000 0000b]
      11. 7.6.11 Register 10: Configuration Register 1 (address = 0Ah) [reset = 0000 0000b]
      12. 7.6.12 Register 11: Configuration Register 2 (address = 0Bh) [reset = 0001 0000b]
      13. 7.6.13 Register 12: Special Functions Register (address = 0Ch) [reset = 0000 0000b]
  8. Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 External Clock Synchronization
      2. 8.1.2 Quiescent Current
      3. 8.1.3 Settling Time
      4. 8.1.4 Overload Recovery
  9. Power Supply Recommendations
  10. 10Device and Documentation Support
    1. 10.1 Receiving Notification of Documentation Updates
    2. 10.2 Support Resources
    3. 10.3 Trademarks
    4. 10.4 Electrostatic Discharge Caution
    5. 10.5 Glossary
  11. 11Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

GPIO Pin Reference

As shown in Figure 54, the PGA280 has seven multi-function pins labeled GPIO0 through GPIO6. These pins can function as general purpose input-output (GPIO) pins either to read a digital input or to output a digital signal as an interrupt or control. GPIO functions are controlled through Register 5 and Register 8.

These pins can also be programmed to have additional special functions for the PGA280. Each of these seven pins can be used as an output for the extended chip select function (ECS), using the PGA280 to redirect the SPI communications to other connected devices. CS Configuration Mode is enabled through Register 9. Additionally, Register 2 controls the clock polarity (CP) of each ECS. For each bit set to 1, a positive edge of SCLK follows CS (CP = 0); for each bit set to 0, a negative edge of SCLK follows CS (CP = 1).

Together with the GPIO and ECS functions, the seven pins can perform more specialized input and output tasks as controlled by Register 12, the Special Functions Register.

GPIO0, GPIO1, and GPIO2 can be used to control an external multiplexer. If the MUX function is enabled in the first three bits of Register 12, the output value on the MUX pins is controlled through Register 0. This configuration allows for simultaneous control of the PGA280 gain and external multiplexer settings by writing to a single register.

GPIO3 can be used to output an error flag. As with bit 3 of Register 4, this option would be the logical OR of the error bits in Register 10 (IARerr, ICAerr, OUTerr, GAINerr, and IOVerr).

GPIO4 can be used as an input to trigger the current buffer. The low-to-high edge of a pulse starts the buffer with a delay of three to four clock cycles. If held high, the buffer [BUFA] remains active. The active time is extended by a minimum of three to four clock cycles in addition to the time set with FLAGTIM.

GPIO5 can be configured as an output to indicate a buffer active condition. The polarity is controlled by BUFApol of bit 5 in Register 10.

GPIO6 can be configured as either an output or an input with the Special Functions Register. With Bit 7, OSCOUT connects the internal oscillator to GPIO6. With Bit 6, SYNCIN allows an external oscillator to provide the master clock to the PGA280.

To use any of these functions, Register 8 must first be set to 0 for input or to 1 for an output (for GPIO, ECS, or special function).

Once set, any 1s in Register 9 supersede the GPIO function for the related pin, allowing for CS configuration.

Likewise, any 1s in Register 12 supersede the GPIO function and CS configuration, allowing for any of the pin-specific special functions to operate.

PGA280 ai_spec_function_pin_assign_bos487.gifFigure 54. Special Function to Pin Assignment Reference