ZHCSS40I march   1994  – march 2021 TL16C550C

PRODUCTION DATA  

  1.   1
  2. 1 特性
  3. 2 说明
  4. 3 Revision History
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1  Absolute Maximum Ratings
    2. 5.2  Recommended Operating Conditions (Low Voltage - 3.3 nominal)
    3. 5.3  Recommended Operating Conditions (Standard Voltage - 5 V nominal)
    4. 5.4  Thermal Information
    5. 5.5  Electrical Characteristics (Low Voltage - 3.3 V nominal)
    6. 5.6  Electrical Characteristics (Standard Voltage - 5 V nominal)
    7. 5.7  System Timing Requirements
    8. 5.8  System Switching Characteristics
    9. 5.9  Baud Generator Switching Characteristics
    10. 5.10 Receiver Switching Characteristics
    11. 5.11 Transmitter Switching Characteristics
    12. 5.12 Modem Control Switching Characteristics
  7. 6 Parameter Measurement Information
  8. 7 Detailed Description
    1. 7.1 Autoflow Control (see )
    2. 7.2 Auto-RTS (see )
    3. 7.3 Auto-CTS (see )
    4. 7.4 Enabling Autoflow Control and Auto-CTS
    5. 7.5 Auto-CTS and Auto-RTS Functional Timing
    6. 7.6 Functional Block Diagram
    7. 7.7 Principles of Operation
      1. 7.7.1  Accessible Registers
      2. 7.7.2  FIFO Control Register (FCR)
      3. 7.7.3  FIFO Interrupt Mode Operation
      4. 7.7.4  FIFO Polled Mode Operation
      5. 7.7.5  Interrupt Enable Register (IER)
      6. 7.7.6  Interrupt Identification Register (IIR)
      7. 7.7.7  Line Control Register (LCR)
      8. 7.7.8  Line Status Register (LSR)
      9. 7.7.9  Modem Control Register (MCR)
      10. 7.7.10 Modem Status Register (MSR)
      11. 7.7.11 Programming Baud Generator
      12. 7.7.12 Receiver Buffet Register (RBR)
      13. 7.7.13 Scratch Register
      14. 7.7.14 Transmitter Holding Register (THR)
  9. 8 Application Information
  10. 9 Device and Documentation Support
    1. 9.1 接收文档更新通知
    2. 9.2 支持资源
    3. 9.3 Trademarks
    4. 9.4 静电放电警告
    5. 9.5 术语表
  11. 10Mechanical, Packaging, and Orderable Information

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7.7.9 Modem Control Register (MCR)

The MCR is an 8-bit register that controls an interface with a modem, data set, or peripheral device that is emulating a modem. The contents of this register are summarized in Table 7-3 and are described in the following bulleted list.

  • Bit 0: This bit (DTR) controls the DTR output
  • Bit 1: This bit (RTS) controls the RTS output
  • Bit 2: This bit (OUT1) controls OUT1, a user-designated output signal.
  • Bit 3: This bit (OUT2) controls OUT2, a user-designated output signal.

When any of bits 0 through 3 are set, the associated output is forced low. When any of these bits are cleared, the associated output is forced high.

  • Bit 4: This bit (LOOP) provides a local loop back feature for diagnostic testing of the ACE. When LOOP is set, the following occurs:
    • The transmitter SOUT is set high.
    • The receiver SIN is disconnected.
    • The output of the TSR is looped back into the receiver shift register input.
    • The four modem control inputs (CTS, DSR, DCD, and RI) are disconnected.
    • The four modem control outputs (DTR, RTS, OUT1, and OUT2) are internally connected to the four modem control inputs.
    • The four modem control outputs are forced to the inactive (high) levels.
  • Bit 5: This bit (AFE) is the autoflow control enable. When set, the autoflow control as described in the detailed description is enabled.

In the diagnostic mode, data that is transmitted is immediately received. This allows the processor to verify the transmit and receive data paths to the ACE. The receiver and transmitter interrupts are fully operational. The modem control interrupts are also operational, but the modem control interrupt’s sources are now the lower four bits of the MCR instead of the four modem control inputs. All interrupts are still controlled by the IER.

The ACE flow can be configured by programming bits 1 and 5 of the MCR as shown in Table 7-8.

Table 7-8 ACE Flow Configuration
MCR BIT 5 (AFE) MCR BIT 1 (RTS) ACE FLOW CONFIGURATION
1 1 Auto-RTS and auto-CTS enabled (autoflow control enabled)
1 0 Auto-CTS only enabled
0 X Auto-RTS and auto-CTS disabled