SWRU626 December 2025 CC3501E , CC3551E
Table 3-549 lists the memory-mapped registers for the SYSTICK registers. All register offset addresses not listed in Table 3-549 should be considered as reserved locations and the register contents should not be modified.
| Offset | Acronym | Register Name | Section |
|---|---|---|---|
| 0h | SYST_CSR | Controls and provides status date for the SysTick timer | Section 3.9.15.1 |
| 4h | SYST_RVR | Specifies the SysTick timer counter reload value | Section 3.9.15.2 |
| 8h | SYST_CVR | Contains the current value of the SysTick counter | Section 3.9.15.3 |
| Ch | SYST_CALIB | Indicates the SysTick calibration value and parameters for the selected security state | Section 3.9.15.4 |
Complex bit access types are encoded to fit into small table cells. Table 3-550 shows the codes that are used for access types in this section.
| Access Type | Code | Description |
|---|---|---|
| Read Type | ||
| R | R | Read |
| Write Type | ||
| W | W | Write |
| Reset or Default Value | ||
| -n | Value after reset or the default value | |
SYST_CSR is shown in Table 3-551.
Return to the Summary Table.
Controls and provides status date for the SysTick timer
| Bit | Field | Type | Reset | Description |
|---|---|---|---|---|
| 31-17 | RES17 | R | 0h | Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. |
| 16 | COUNTFLAG | R/W | 0h | Indicates whether the counter has counted to zero since the last read of this register |
| 15-3 | RES3 | R | 0h | Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. |
| 2 | CLKSOURCE | R/W | 0h | Indicates the SysTick clock source |
| 1 | TICKINT | R/W | 0h | Indicates whether counting to 0 causes the status of the SysTick exception to change to pending |
| 0 | ENABLE | R/W | 0h | Indicates the enabled status of the SysTick counter |
SYST_RVR is shown in Table 3-552.
Return to the Summary Table.
Specifies the SysTick timer counter reload value
| Bit | Field | Type | Reset | Description |
|---|---|---|---|---|
| 31-24 | RES24 | R | 0h | Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. |
| 23-0 | RELOAD | R/W | Xh | Value to load into the SYST_CVR when the counter is enabled and when it reaches 0 |
SYST_CVR is shown in Table 3-553.
Return to the Summary Table.
Contains the current value of the SysTick counter
| Bit | Field | Type | Reset | Description |
|---|---|---|---|---|
| 31-24 | RES24 | R | 0h | Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. |
| 23-0 | CURRENT | W | Xh | Reads the current value of the SysTick counter. A write of any value clears the field to 0, and also clears the SYST_CSR.COUNTFLAG bit to 0. |
SYST_CALIB is shown in Table 3-554.
Return to the Summary Table.
Indicates the SysTick calibration value and parameters for the selected security state
| Bit | Field | Type | Reset | Description |
|---|---|---|---|---|
| 31 | RES24_2 | R | 0h | Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. |
| 30 | SKEW | R | 0h | Indicates whether the TENMS value is exact |
| 29-24 | RES24 | R | 0h | Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. |
| 23-0 | TENMS | R | Xh | Reload value for 10ms (100Hz) timing, subject to system clock skew errors. If the value reads as zero, the calibration value is not known. |