SLAS564I August   2007  – December 2024 CDCE937 , CDCEL937

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Timing Requirements: CLK_IN
    7. 5.7 Timing Requirements: SDA/SCL
    8. 5.8 EEPROM Specification
    9. 5.9 Typical Characteristics
  7. 6 Parameter Measurement Information
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Control Terminal Setting
      2. 7.3.2 Default Device Setting
      3. 7.3.3 SDA/SCL Serial Interface
      4. 7.3.4 Data Protocol
    4. 7.4 Device Functional Modes
      1. 7.4.1 SDA/SCL Hardware Interface
    5. 7.5 Programming
  9. 8 Register Maps
    1. 8.1 SDA/SCL Configuration Registers
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Spread Spectrum Clock (SSC)
        2. 9.2.2.2 PLL Frequency Planning
        3. 9.2.2.3 Crystal Oscillator Start-Up
        4. 9.2.2.4 Frequency Adjustment With Crystal Oscillator Pulling
        5. 9.2.2.5 Unused Inputs and Outputs
        6. 9.2.2.6 Switching Between XO and VCXO Mode
      3. 9.2.3 Application Curves
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Third-Party Products Disclaimer
      2. 10.1.2 Development Support
    2. 10.2 Documentation Support
      1. 10.2.1 Related Documentation
    3. 10.3 Receiving Notification of Documentation Updates
    4. 10.4 Support Resources
    5. 10.5 Trademarks
    6. 10.6 Electrostatic Discharge Caution
    7. 10.7 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

7.3.4 Data Protocol

The device supports Byte Write and Byte Read and Block Write and Block Read operations.

For Byte Write/Read operations, the system controller can individually access addressed bytes.

For Block Write/Read operations, the bytes are accessed in sequential order from lowest to highest byte (with most significant bit first) with the ability to stop after any complete byte has been transferred. The numbers of Bytes read-out are defined by Byte Count in the Generic Configuration Register. At Block Read instruction all bytes defined in the Byte Count has to be readout to correctly finish the read cycle.

Once a byte has been sent, the byte is written into the internal register and is effective immediately. This applies to each transferred byte independent of whether this is a Byte Write or a Block Write sequence.

If the EEPROM write cycle is initiated, the internal registers are written into the EEPROM. Data can be read out during the programming sequence (Byte Read or Block Read). The programming status can be monitored by EEPIP, byte 01h–bit 6. Before beginning EEPROM programming, pull CLKIN LOW. CLKIN must be held LOW for the duration of EEPROM programming. After initiating EEPROM programming with EEWRITE, byte 06h-bit 0, do not write to the device registers until EEPIP is read back as a 0.

The offset of the indexed byte is encoded in the command code, as described in Target Receiver Address (7 Bits).

Table 7-5 Target Receiver Address (7 Bits)
DEVICEA6A5A4A3A2A1(1)A0(1)R/ W
CDCEx91311001011/0
CDCEx92511001001/0
CDCEx93711011011/0
CDCEx94911011001/0
(1) Address bits A0 and A1 are programmable through the SDA/SCL bus (Byte 01, Bit [1:0]). This allows addressing up to 4 devices connected to the same SDA/SCL bus. The least-significant bit of the address byte designates a write or read operation.