Instance: SYSTICK
Component: SYSTICK
Base address: 0xE000E010
Register Name |
Type |
Register Width (Bits) |
Register Reset |
Address Offset |
Physical Address |
32 |
0x0000 0000 |
0x0000 0000 |
0xE000 E010 |
||
32 |
0x0000 0000 |
0x0000 0004 |
0xE000 E014 |
||
32 |
0x0000 0000 |
0x0000 0008 |
0xE000 E018 |
||
32 |
0x0000 0000 |
0x0000 000C |
0xE000 E01C |
Address Offset | 0x0000 0000 | ||
Physical Address | 0xE000 E010 | Instance | 0xE000 E010 |
Description | Use the SysTick Control and Status Register to enable the SysTick features. | ||
Type |
Bits | Field Name | Description | Type | Reset | ||
31:17 | RESERVED17 | Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. | RO | 0b000 0000 0000 0000 | ||
16 | COUNTFLAG | Returns 1 if timer counted to 0 since last time this was read. Clears on read by application or debugger. | RO | 0 | ||
15:3 | RESERVED3 | Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. | RO | 0b0 0000 0000 0000 | ||
2 | CLKSOURCE | SysTick clock source. Always reads as one if STCALIB reports NOREF. 0x0:Systick driven by external reference clock. 0x1:Systick driven by processor clock, hclk. |
RO | 0 | ||
1 | TICKINT | 0x0:Counting down to zero does not pend the systick handler. software can use countflag to determine if the systick handler has ever counted to zero. 0x1:Counting down to zero pends the systick handler. |
RW | 0 | ||
0 | ENABLE | Enable SysTick counter 0x0:Counter disabled 0x1:Counter operates in a multi-shot way. that is, counter loads with the reload value and then begins counting down. on reaching 0, it sets the countflag to 1 and optionally pends the systick handler, based on tickint. it then loads the reload value again, and begins counting. |
RW | 0 |
Address Offset | 0x0000 0004 | ||
Physical Address | 0xE000 E014 | Instance | 0xE000 E014 |
Description | Use the SysTick Reload Value Register to specify the start value to load into the current value register when the counter reaches 0. It can be any value between 0 and 0x00FFFFFF. A start value of 0 is possible, but has no effect because the SysTick interrupt and COUNTFLAG are activated when counting from 1 to 0. The reset value of this register is UNKNOWN. | ||
Type |
Bits | Field Name | Description | Type | Reset | ||
31:24 | RESERVED24 | Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. | RO | 0x00 | ||
23:0 | RELOAD | Value to load into the SysTick Current Value Register when the counter reaches 0. | RW | 0x00 0000 |
Address Offset | 0x0000 0008 | ||
Physical Address | 0xE000 E018 | Instance | 0xE000 E018 |
Description | Use the SysTick Current Value Register to find the current value in the register. The reset value of this register is UNKNOWN. | ||
Type |
Bits | Field Name | Description | Type | Reset | ||
31:24 | RESERVED24 | Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. | RO | 0x00 | ||
23:0 | CURRENT | Reads return the current value of the SysTick counter. This register is write-clear. Writing to it with any value clears the register to 0. Clearing this register also clears the COUNTFLAG bit of the SysTick Control and Status Register. | RW | 0x00 0000 |
Address Offset | 0x0000 000C | ||
Physical Address | 0xE000 E01C | Instance | 0xE000 E01C |
Description | Use the SysTick Calibration Value Register to enable software to scale to any required speed using divide and multiply. | ||
Type |
Bits | Field Name | Description | Type | Reset | ||
31 | NOREF | If reads as 1, the Reference clock is not provided - the CLKSOURCE bit of the SysTick Control and Status register will be forced to 1 and cannot be cleared to 0. | RO | 0 | ||
30 | SKEW | If reads as 1, the calibration value for 10ms is inexact (due to clock frequency). | RO | 0 | ||
29:24 | RESERVED24 | Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. | RO | 0b00 0000 | ||
23:0 | TENMS | An optional Reload value to be used for 10ms (100Hz) timing, subject to system clock skew errors. If the value reads as 0, the calibration value is not known. | RO | 0x00 0000 |
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