SPRAD62 February   2023 TMS320F280023C , TMS320F280025C , TMS320F280025C-Q1 , TMS320F280037C , TMS320F280037C-Q1 , TMS320F280038C-Q1 , TMS320F280039C , TMS320F280039C-Q1 , TMS320F28386D , TMS320F28386D-Q1 , TMS320F28386S , TMS320F28386S-Q1 , TMS320F28388D , TMS320F28388S , TMS320F28P650DH , TMS320F28P650DK , TMS320F28P650SH , TMS320F28P650SK , TMS320F28P659DK-Q1

 

  1.   Abstract
  2.   Trademarks
  3. 1Introduction
  4. 2Serial Port Design Methodology
    1. 2.1 Step 1: Understand Design Requirements
    2. 2.2 Step 2: Identify Required Inputs to the CLB Tile
      1. 2.2.1 GPIO Input Qualification
      2. 2.2.2 CLB Input Settings
    3. 2.3 Step 3: Identify Required Outputs from CLB Logic
      1. 2.3.1 Synchronizing Outputs Signals
      2. 2.3.2 Output Signal Conditioning
    4. 2.4 Step 4: Design the CLB Logic
      1. 2.4.1 Resource Allocation
      2. 2.4.2 Exchanging Data Between CLB FIFOs and MCU RAM
      3. 2.4.3 CLB Logic Status and Trigger Flags
        1. 2.4.3.1 Status/Flag Bits
        2. 2.4.3.2 Trigger Bits
    5. 2.5 Step 5: Simulate the Logic Design
    6. 2.6 Step 6: Test the CLB Logic
  5. 3Example A: Using the CLB to Input and Output a TDM Stream in Audio Applications
    1. 3.1 Example Overview
    2. 3.2 Step 1: Understand Design Requirements
    3. 3.3 Step 2: Identify Required Inputs to the CLB Tile
    4. 3.4 Step 3: Identify Required Outputs from CLB Logic
    5. 3.5 Step 4: Design the CLB Logic
      1. 3.5.1 Resource Allocation
      2. 3.5.2 TDM Word Counter
      3. 3.5.3 FSYNC and DATA1 Output Synchronization
    6. 3.6 Step 5: Simulate the Logic Design
    7. 3.7 Step 6: Test the CLB Logic
      1. 3.7.1 Hardware Setup and Connections
      2. 3.7.2 Software Setup
      3. 3.7.3 Testing Output Setup and Hold Times
      4. 3.7.4 Testing Data Integrity
  6. 4Example B: Using the CLB to Implement a Custom Communication Bus for LED Driver in Lighting Applications
    1. 4.1 Example Overview
    2. 4.2 Step 1: Understand Design Requirements
    3. 4.3 Step 2: Identify Required Inputs to the CLB Tile
    4. 4.4 Step 3: Identify Required Outputs From CLB Logic
    5. 4.5 Step 4: Design the CLB Logic
      1. 4.5.1 TX Tile Logic
      2. 4.5.2 RX Tile Logic
      3. 4.5.3 Data Clocking
    6. 4.6 Step 5: Simulate the Logic Design
    7. 4.7 Step 6: Test the CLB Logic
      1. 4.7.1 Hardware Setup and Connections
      2. 4.7.2 Software Setup
      3. 4.7.3 Testing Output Setup and Hold Times
  7. 5References

2.2.2 CLB Input Settings

Each of the eight CLB inputs have different configuration and filter options which must be carefully considered depending on the switching characteristics of the serial bus. Table 2-3 and Table 2-4 list the different options and their possible uses.

Table 2-3 CLB Input Configuration Options
Input Configuration Setting Description Uses
Asynchronous input The input signal is not synchronized to SYSCLKOUT. Use for passing signals unchanged through the CLB tile and directly to the CLB outputs.
Synchronization to SYSCLKOUT (recommended setting) The input signal is synchronized to SYSCLKOUT. Generally, it is required to synchronize all CLB inputs used in tile logic blocks.
Table 2-4 CLB Input Filter Options
Input Filter Setting Description Uses
No filtering The input signal is passed directly to the CLB tile. Use for designing logic that depends on the logical state of the input. For example, enable & disable signals.
Rising-edge detect A single pulse equal to a CLB clock will be generated when a rising-edge is detected on the input signal. Use for shifting data in or out of the counters in serializer mode or for counting serial clock edges.
Falling-edge detect A single pulse equal to a CLB clock will be generated when a falling-edge is detected on the input signal. Use for shifting data in or out of the counters in serializer mode or for counting serial clock edges.
Any-edge detect A single pulse equal to a CLB clock will be generated when a falling-edge or rising-edge is detected on the input signal. Use for logic that needs to act on both edges of an input signal.

A single external input may need to be mapped to multiple CLB tile inputs with different input filter settings. This allows part of the CLB tile logic to operate off the rising edge of an external signal and separate logic to operate off the falling edge of the same signal. Mapping of a single external signal to multiple CLB inputs is used in the two examples given in this application report.