RM0352 datasheet(69/138 Pages) STMICROELECTRONICS

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RM0352

System timer (SysTick)

137

Type:

R/W

Reset:

Description:

SysTick reload value register

To generate a multi-shot timer with a period of N processor clock cycles, use a RELOAD

value of N-1. For example, if the SysTick interrupt is required every 100 clock pulses, set

RELOAD to 99.

9.3.3

SysTick current value register (SYST_CVR)

Address:

SysTick BaseAddress + 0x008

Type:

R/W

Reset:

Description:

SysTick current value register

9.3.4

SysTick calibration value register (SYST_CALIB)

Address:

SysTick BaseAddress + 0x00C

Type:

R/O

[31:24]

RESERVED

[23:0]

RELOAD: value to load into the SYST_CVR when the counter is enabled and

when reaches zero.

The RELOAD value can be any value in the range 0x00000001-0x00FFFFFF.

Programming 0x00000000 has no effect because the SysTick exception

request and COUNTFLAG are activated when counting down from 1 to 0.

Table 68. SysTick current value register

SysTick current value register (SYST_CVR)

31 30 29 28 27 26 25 24 23 22 21 20 19 18 17

15 14 13 12 11 10

RESERVED

CURRENT

[31:24]

RESERVED

[23:0]

CURRENT: read returns the current value of the SysTick counter.

A write of any value clears the field to zero and clears the

SYST_CSR.COUNTFLAG bit to zero.

Table 69. SysTick calibration value register

SysTick calibration value register (SYST_CALIB)

29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10

9876

543210

NOREF SKEW

RESERVED

TENMS

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