CSR Bit Fields

RISC-V tcontrol CSR Register

Address 0x7A5Privilege Machine/DebugAccess RW / XLENDebug, trace, and trigger CSRs

tcontrol at 0x7A5 is a Debug trigger CSR: is a standard named CSR in the Debug trigger category.

Field Map

Understand tcontrol By Bit Fields

1 key fields
XLEN-1:0

VALUE

RW

Full register value of tcontrol; bits not split out here follow the relevant extension or privileged specification, and reserved or WPRI fields should be preserved when writing other fields and ignored on reads.

VALUE (bits XLEN-1:0) — Full register value of tcontrol; bits not split out here follow the relevant extension or privileged specification, and reserved or WPRI fields should be preserved when writing other fields and ignored on reads.

What This Field Controls

  • - Full register value of tcontrol; bits not split out here follow the relevant extension or privileged specification, and reserved or WPRI fields should be preserved when writing other fields and ignored on reads.

Common Values

This field is better understood together with surrounding context than as a fixed memorized enumeration.

Open Official Manual

What To Check First When Reading This CSR

  • - First confirm that the current hart implements tcontrol; unimplemented or insufficiently privileged accesses raise an illegal-instruction exception.
  • - Use address 0x7A5 and the lowest access privilege (Machine/Debug) to decide whether software may read it directly.
  • - Do not assume fixed values for reserved, WARL, or WLRL bits; interpret the value according to the specification and implementation.

Risk Checks Before Writing

  • - Preserve bits that are not being changed so reserved or implementation-defined fields are not written with invalid values.
  • - Prefer CSRRS/CSRRC for local set/clear operations to avoid CSRRW overwriting concurrently updated status bits.

Put It Back Into A Real Flow

1

During initialization or the relevant privileged flow, software reads tcontrol to observe the current state.

2

Modify only the target fields while preserving all other bits.

3

Read back the CSR or validate through later trap, interrupt, or context-switch behavior that the setting took effect.