`std/delay` — Delays¶

import std/delay

Blocking busy-wait delays, built on the @burn intrinsic. Nothing here uses a timer, so the delays hold the CPU and their accuracy depends on knowing the clock frequency.

Defining your clock¶

The public delay functions scale themselves to the CPU clock by calling a @cpu_mhz() function that you define once per project. It is not built in, because only you know your board’s clock. AVR parts often ship on the internal RC oscillator (commonly 1 or 8 MHz); a common external-crystal clock is 16 MHz:

@cpu_mhz() -> u16 { return 16 }     # or 8, or 1, to match your hardware

If you do not want this dependency, call the underscore-prefixed primitives and pass the clock explicitly.

Public delays¶

@delay_ms($ms: u16)¶: Delay for approximately $ms milliseconds, using the project clock from @cpu_mhz().

@delay_us($us: u16)¶: Delay for approximately $us microseconds, using the project clock from @cpu_mhz(). Very short waits are dominated by call overhead.

Explicit-clock primitives¶

@_delay_ms($ms: u16, $clock_mhz: u16)¶: Delay for approximately $ms milliseconds at a CPU clock of $clock_mhz MHz (e.g. 8 or 16). The public @delay_ms wraps this.

@_delay_us($us: u16, $clock_mhz: u16)¶

Delay for approximately $us microseconds at a CPU clock of $clock_mhz MHz.

The product $us * $clock_mhz must fit in 16 bits — about 16,000 µs at 16 MHz. For longer waits use @delay_ms.

Example¶

target atmega328p
import std/gpio
import std/delay

@cpu_mhz() -> u16 { return 16 }    # tell the delay library our clock is 16 MHz

@main {
    @pin_mode_b(5, 1)              # LED pin as output
    loop * {
        @digital_write_b(5, 1)     # LED on
        @delay_ms(500)             # wait half a second
        @digital_write_b(5, 0)     # LED off
        @delay_ms(500)             # wait again -> a 1 Hz blink
    }
}

std/delay — Delays¶

Defining your clock¶

Public delays¶

Explicit-clock primitives¶

Example¶

`std/delay` — Delays¶