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SysTick.mod
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SysTick.mod
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MODULE SysTick;
(**
Oberon RTK Framework
System tick
for Kernel v2: use sys tick interrupt
--
Each core has its own sys tick, ie. registers
are not shared.
--
MCU: Cortex-M0+ RP2040, tested on Pico
--
Copyright (c) 2020-2024 Gray, gray@grayraven.org
https://oberon-rtk.org/licences/
**)
IMPORT SYSTEM, MCU := MCU2, Exceptions;
CONST
(* bits *)
SYST_CSR_COUNTFLAG = 16;
SYST_CSR_ENABLE = 0;
SYST_CSR_TICKINT = 1;
CountPerMillisecond = MCU.SysTickFreq DIV 1000;
PROCEDURE InstallHandler*(handler: PROCEDURE);
BEGIN
Exceptions.InstallExcHandler(MCU.SysTickHandlerOffset, handler)
END InstallHandler;
PROCEDURE SetPrio*(prio: INTEGER);
BEGIN
Exceptions.SetSysExcPrio(Exceptions.SysExcSysTickNo, prio)
END SetPrio;
PROCEDURE Enable*;
BEGIN
SYSTEM.PUT(MCU.SYST_CSR, {SYST_CSR_TICKINT, SYST_CSR_ENABLE})
END Enable;
PROCEDURE Init*(millisecondsPerTick: INTEGER);
VAR cntReload: INTEGER;
BEGIN
cntReload := millisecondsPerTick * CountPerMillisecond - 1;
SYSTEM.PUT(MCU.SYST_RVR, cntReload);
SYSTEM.PUT(MCU.SYST_CVR, 0) (* clear counter *)
END Init;
END SysTick.