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

2.4.3.1 Status/Flag Bits

Status/flag bits allow the CPU to poll the state of the CLB logic. For example, after a CLB interrupt, the CPU can poll a flag bit to determine if the interrupt was due a data receive interrupt or a receive error interrupt.

These status/flag bits can be implemented using the HLC registers. However, one HLC register has to be used per flag since there is no bitwise AND or OR instruction supported by the HLC. For example, a non-zero value in HLC R0 register could be used to indicate a receive interrupt, while a non-zero value in R1 could be used to indicate a receive error.

Note: The HLC “INTR <tag>” instruction and CLB_INTR_TAG_REG cannot be used for flags since subsequent uses of this instruction will overwrite any previous tag values.

The CLB logic status can also be determined by directly reading the status of the different CLB logic blocks. For example, if an FSM is configured to define multiple states, e.g. IDLE and ACTIVE, the CPU can read the status of S0 and S1 to determine the CLB logic state.

The CPU can use the CLB memory-mapped debug registers CLB_DBG_Rn, CLB_DBG_Cn, and CLB_DBG_OUT to determine the status of different blocks within the CLB. An example of using HLC registers as status bits is shown in the following code block. The code block uses C2000ware driverlib functions.

uint32_t chkIntFlag = CLB_getRegister(CCSI2_RX_TILE_BASE, CLB_REG_HLC_R1);
uint32_t rcvIntFlag = CLB_getRegister(CCSI2_RX_TILE_BASE, CLB_REG_HLC_R2);
uint32_t endIntFlag = CLB_getRegister(CCSI2_RX_TILE_BASE, CLB_REG_HLC_R3);

    ...

    // Receive interrupt
    if (rcvIntFlag & 0x1)
    {
        ...
        // Clear the receive interrupt flag register
        CLB_writeInterface(CCSI2_RX_TILE_BASE, CLB_ADDR_HLC_R2, 0x0);
    }

    // End interrupt
    if (endIntFlag & 0x1)
    {
        ...
        // Clear the end interrupt flag register
        CLB_writeInterface(CCSI2_RX_TILE_BASE, CLB_ADDR_HLC_R3, 0x0);
    }

    // Check error interrupt
    if (chkIntFlag & 0x1)
    {
        ...
        // Clear the check error interrupt flag register
        CLB_writeInterface(CCSI2_RX_TILE_BASE, CLB_ADDR_HLC_R1, 0x0);
    }