uv-k5-firmware-custom/driver/systick.c
2023-09-09 08:03:56 +01:00

55 lines
1.2 KiB
C

/* Copyright 2023 Dual Tachyon
* https://github.com/DualTachyon
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "ARMCM0.h"
#include "driver/systick.h"
#include "misc.h"
// 0x20000324
static uint32_t gTickMultiplier;
void SYSTICK_Init(void)
{
SysTick_Config(480000);
gTickMultiplier = 48;
}
void SYSTICK_DelayUs(uint32_t Delay)
{
uint32_t i;
uint32_t Start;
uint32_t Previous;
uint32_t Current;
uint32_t Delta;
i = 0;
Start = SysTick->LOAD;
Previous = SysTick->VAL;
do {
do {
Current = SysTick->VAL;
} while (Current == Previous);
if (Current < Previous) {
Delta = -Current;
} else {
Delta = Start - Current;
}
i += Delta + Previous;
Previous = Current;
} while (i < Delay * gTickMultiplier);
}