embassy-rs/embassy · error

Timer does not exist

Error message

Timer does not exist

What it means

generate_timers iterates every TIM* (non-TIMB) peripheral of the chip and looks up its configuration in the static TIMERS table, panicking if the timer model is unknown. The TIMERS map must contain an entry (bit width, capabilities) for every timer instance present in the package metadata.

Solutions

1. Add an entry for the missing timer (with its bits/capabilities) to the TIMERS map in embassy-mspm0/build.rs.
2. Build against a chip variant whose timers are all covered by the TIMERS table.
3. Report the missing timer for your part number upstream so the table is extended.

Example fix

// before (TIMERS map)
"TIMG0": TimerInfo { bits: 16, .. },
// after
"TIMG0": TimerInfo { bits: 16, .. },
"TIMG12": TimerInfo { bits: 32, .. },

// verify all TIM peripherals have a TIMERS entry before building
let missing: Vec<_> = metadata.peripherals.iter()
    .filter(|p| p.name.starts_with("TIM") && !p.name.starts_with("TIMB"))
    .filter(|p| !TIMERS.contains_key(p.name.as_str()))
    .map(|p| p.name.clone()).collect();
assert!(missing.is_empty(), "timers missing from TIMERS map: {:?}", missing);

When it happens

Trigger: Building embassy-mspm0 for a package containing a TIM-prefixed peripheral (e.g. a newly added TIMG12 or another timer variant) that has no corresponding key in the build script's TIMERS map, during generate_code -> generate_timers.

Common situations: A new MSPM0 device family introduces a timer instance not yet listed in the TIMERS table; a metadata peripheral name spelling differs from the TIMERS keys; upstream added a chip before updating the timer table.

Understand the failure class

Background: 'Could not be found', 'does not exist', 'not found in database': the resource-not-found family when an ID, slug, key, or URI lookup comes back empty — this error's family across 20 libraries.

Related errors

• Could not find any timer
• no SYSCTL peripheral
• Could not find NRST pin to cfg gate
• Could not find DEBUGSS peripheral
• Could not find SWD pin to cfg gate

AI-assisted analysis of embassy-rs/embassy@463a07b963 (2026-09-10). Data as JSON: /api/errors/e4c6f302e2194d13. Report an issue: GitHub.

Appendix: source

Thrown at embassy-mspm0/build.rs:583

    quote! {
        embassy_hal_internal::peripherals_definition!(#(#singletons_peripherals_def),*);
        embassy_hal_internal::peripherals_struct!(#(#singletons_peripherals_struct),*);
    }
}

fn generate_timers() -> TokenStream {
    // Generate timers
    let timer_impls = METADATA
        .peripherals
        .iter()
        .filter(|p| p.name.starts_with("TIM"))
        .filter(|p| !p.name.starts_with("TIMB"))
        .map(|peripheral| {
            let name = Ident::new(&peripheral.name, Span::call_site());
            let timers = &*TIMERS;

            let timer = timers.get(peripheral.name).expect("Timer does not exist");
            assert!(timer.bits == 16 || timer.bits == 32);
            let bits = if timer.bits == 16 {
                quote! { Bits16 }
            } else {
                quote! { Bits32 }
            };

            let mut impls = Vec::new();
            let prescaler = timer.prescaler;
            let channels = timer.ccp_channels_external;

            impls.push(quote! {
                impl_tim_instance!(
                    #name,
                    prescaler: #prescaler,
                    width: #bits,
                    channels: #channels
                );

View on GitHub (pinned to 463a07b963)