SPRUIY2 November   2024 F29H850TU , F29H859TU-Q1

 

  1.   1
  2.   Read This First
    1.     About This Manual
    2.     Related Documentation from Texas Instruments
    3.     Glossary
    4.     Support Resources
    5.     Trademarks
  3. 1Architecture Overview
    1. 1.1 Introduction to the CPU
    2. 1.2 Data Type
    3. 1.3 C29x CPU System Architecture
      1. 1.3.1 Emulation Logic
      2. 1.3.2 CPU Interface Buses
    4. 1.4 Memory Map
  4. 2Central Processing Unit (CPU)
    1. 2.1 C29x CPU Architecture
      1. 2.1.1 Features
      2. 2.1.2 Block Diagram
    2. 2.2 CPU Registers
      1. 2.2.1 Addressing Registers (Ax/XAx)
      2. 2.2.2 Fixed-Point Registers (Dx/XDx)
      3. 2.2.3 Floating Point Register (Mx/XMx)
      4. 2.2.4 Program Counter (PC)
      5. 2.2.5 Return Program Counter (RPC)
      6. 2.2.6 Status Registers
        1. 2.2.6.1 Interrupt Status Register (ISTS)
        2. 2.2.6.2 Decode Phase Status Register (DSTS)
        3. 2.2.6.3 Execute Phase Status Register (ESTS)
    3. 2.3 Instruction Packing
      1. 2.3.1 Standalone Instructions and Restrictions
      2. 2.3.2 Instruction Timeout
    4. 2.4 Stacks
      1. 2.4.1 Software Stack
      2. 2.4.2 Protected Call Stack
      3. 2.4.3 Real Time Interrupt / NMI Stack
  5. 3Interrupts
    1. 3.1 CPU Interrupts Architecture Block Diagram
    2. 3.2 RESET, NMI, RTINT, and INT
      1. 3.2.1 RESET (CPU reset)
      2. 3.2.2 NMI (Non-Maskable Interrupt)
      3. 3.2.3 RTINT (Real Time Interrupt)
      4. 3.2.4 INT (Low-Priority Interrupt)
    3. 3.3 Conditions Blocking Interrupts
      1. 3.3.1 ATOMIC Counter
    4. 3.4 CPU Interrupt Control Registers
      1. 3.4.1 Interrupt Status Register (ISTS)
      2. 3.4.2 Decode Phase Status Register (DSTS)
      3. 3.4.3 Interrupt-Related Stack Registers
    5. 3.5 Interrupt Nesting
      1. 3.5.1 Interrupt Nesting Example Diagram
    6. 3.6 Security
      1. 3.6.1 Overview
      2. 3.6.2 LINK
      3. 3.6.3 STACK
      4. 3.6.4 ZONE
  6. 4Pipeline
    1. 4.1  Introduction
    2. 4.2  Decoupled Pipeline Phases
    3. 4.3  Dual Instruction Prefetch Buffers
    4. 4.4  Pipeline Advancement and Stalls
    5. 4.5  Pipeline Hazards and Protection Mechanisms
    6. 4.6  Register Updates and Corresponding Pipeline Phases
    7. 4.7  Register Reads and Writes During Normal Operation
    8. 4.8  D2 Read Protection
    9. 4.9  E1 Read Protection
    10. 4.10 WAW Protection
    11. 4.11 Protection During Interrupt
  7. 5Addressing Modes
    1. 5.1 Addressing Modes Overview
      1. 5.1.1 Documentation and Implementation
      2. 5.1.2 List of Addressing Mode Types
        1. 5.1.2.1 Additional Types of Addressing
      3. 5.1.3 Addressing Modes Summarized
    2. 5.2 Addressing Mode Fields
      1. 5.2.1 ADDR1 Field
      2. 5.2.2 ADDR2 Field
      3. 5.2.3 ADDR3 Field
      4. 5.2.4 DIRM Field
      5. 5.2.5 Additional Fields
    3. 5.3 Alignment and Pipeline Considerations
      1. 5.3.1 Alignment
      2. 5.3.2 Pipeline Considerations
    4. 5.4 Types of Addressing Modes
      1. 5.4.1 Direct Addressing
      2. 5.4.2 Pointer Addressing
        1. 5.4.2.1 Pointer Addressing with #Immediate Offset
        2. 5.4.2.2 Pointer Addressing with Pointer Offset
        3. 5.4.2.3 Pointer Addressing with #Immediate Increment/Decrement
        4. 5.4.2.4 Pointer Addressing with Pointer Increment/Decrement
      3. 5.4.3 Stack Addressing
        1. 5.4.3.1 Allocating and De-allocating Stack Space
      4. 5.4.4 Circular Addressing Instruction
      5. 5.4.5 Bit Reversed Addressing Instruction
  8. 6Safety and Security Unit (SSU)
    1. 6.1 SSU Overview
    2. 6.2 Links and Task Isolation
    3. 6.3 Sharing Data Outside Task Isolation Boundary
    4. 6.4 Protected Call and Return
  9. 7Emulation
    1. 7.1 Overview of Emulation Features
    2. 7.2 Debug Terminology
    3. 7.3 Debug Interface
    4. 7.4 Execution Control Mode
    5. 7.5 Breakpoints, Watchpoints, and Counters
      1. 7.5.1 Software Breakpoint
      2. 7.5.2 Hardware Debugging Resources
        1. 7.5.2.1 Hardware Breakpoint
        2. 7.5.2.2 Hardware Watchpoint
        3. 7.5.2.3 Benchmark Counters
      3. 7.5.3 PC Trace
  10. 8Revision History

3.2.4 INT (Low-Priority Interrupt)

The INT (low-priority interrupt) is the lowest-priority interrupt line, and receives signals driven by an interrupt expansion and aggregation unit (the PIPE module for most C29x CPU systems). This interrupt line is typically used for lower priority operations and task schedulers.

Blocking and Masking

INT sources are able to be masked, and the INT line can also be blocked/disabled by user code using the DSTS.INTE enable bit. If DSTS.INTE is enabled, then any interrupts received on the INT line are directly passed to the CPU for prioritization. Priority is then decided among the interrupts on the NMI or RTINT lines. To prevent an RTINT interrupt from nesting within a INT interrupt, the ATOMIC instruction can be used for a finite number of instruction packets.

On entering a INT ISR, further INTs are automatically disabled using the DSTS.INTE bit. To allow nesting, enable interrupts using the ENINT instruction. There also exists a DISINT instruction for disabling the INT line again.

The C29x CPU also provides a special INT called as Supervisor Interrupt. Supervisor Interrupt is essentially an INT which can override the DSTS.INTE setting. For example, Supervisor Interrupt can be a certain task monitor interrupt which requires the interrupt to not get blocked by erroneous setting of the DSTS.INTE.

Signal Propagation

The PIPE module provides external interrupt aggregation and arbitration for the RTINT and INT lines. This allows for many signals to be categorized as "real-time interrupts" ("RTINT") or "low-priority interrupts" ("INT"), and then prioritized before passing to the CPU's RTINT or INT interrupt line.

The PIPE effectively multiplexes the single INT CPU interrupt line to be able to receive from multiple incoming INT interrupts in the appropriate order.

The module allows for enabling and disabling of INT signals before the signals reach the INT line of the CPU. The module also allows nesting capability amongst other interrupts categorized as INT or RTINT. See the F29H85x and F29P58x Real-Time Microcontrollers Technical Reference Manual for details on the PIPE module features.

Stack

Unlike the NMI or RTINT interrupt lines, the INT line uses the standard software stack for context save and restore. Only one of the multiple available CPU stacks can be used for INT. This is configured by the INTSP register in the external PIPE module. If an INT vector points to the wrong LINK which is associated with a different STACK (security-assigned stack), then an NMI fault is generated.

If the current stack pointer is not pointing to the INTSP, then any pending INT remains pending until the stack pointer points to the selected INTSP stack.