1.3 Register Bit Types
The following table describes the register bit attributes used throughout this document.
| Register Bit Type Notation | Register Bit Description |
|---|---|
| R | Read: A register or bit with this attribute can be read. |
| W | Write: A register or bit with this attribute can be written. |
| RO | Read Only: A register or bit with this attribute is read only; writing has no effect. |
| WO | Write Only: If a register or bit is write-only, reads will return unspecified data. |
| W1S | Write One to Set: Writing a one sets the value. Writing a zero has no effect. |
| W1C | Write One to Clear: Writing a one clears the value. Writing a zero has no effect. |
| RC | Read to Clear: Content is cleared after the read. Writes have no effect. |
| SC | Self Clearing: A bit with this attribute will be cleared to ‘0’ after being written as ‘1’. Hardware often clears such bits following the completion of some action initiated by the write. |
| NASR | Not Affected by Software Reset: The state of NASR bits do not change on assertion of a software reset. |
Many of these register bit notations can be combined. Some examples of this are:
- R/W: Can be written. Will return current setting on a read.
- R/W SC: Bit is readable. When set, it will automatically be cleared by hardware once some action is complete.
- R/W1C: Bit is readable. Write a ‘1’ to this bit to clear.