Files
Embedded-Hacking/drivers/0x03_button_cbm/Src/rp2350_delay.c
T
Kevin Thomas afdc1fa594 Add 0x03_button_cbm: bare-metal RP2350 button driver
- GPIO15 active-low button input with internal pull-up
- 20ms software debounce via busy-wait confirmation
- LED mirrors button state, UART reports edge transitions
- New gpio_config_input_pullup() in GPIO driver
- 1555B FLASH, 13 source files, zero warnings
2026-04-05 16:06:46 -04:00

40 lines
1.0 KiB
C

/**
******************************************************************************
* @file rp2350_delay.c
* @author Kevin Thomas
* @brief Delay driver implementation for RP2350.
*
* Busy-wait millisecond delay calibrated for a 14.5 MHz clock
* (3600 loop iterations per millisecond).
*
******************************************************************************
* @attention
*
* Copyright (c) 2026 Kevin Thomas.
* All rights reserved.
*
* This software is licensed under terms that can be found in the LICENSE file
* in the root directory of this software component.
* If no LICENSE file comes with this software, it is provided AS-IS.
*
******************************************************************************
*/
#include "rp2350_delay.h"
void delay_ms(uint32_t ms)
{
if (ms == 0)
return;
__asm__ volatile (
"mov r4, #3600\n\t"
"mul r5, %0, r4\n\t"
"1:\n\t"
"subs r5, #1\n\t"
"bne 1b\n\t"
:
: "r" (ms)
: "r4", "r5", "cc"
);
}