ESP32: add support to light sleep by bettio · Pull Request #1789 · atomvm/AtomVM

bettio · 2025-08-08T13:20:28Z

Allow putting ESP32 to light sleep, and wake it up using a GPIO or a timer.

These changes are made under both the "Apache 2.0" and the "GNU Lesser General
Public License 2.1 or later" license terms (dual license).

SPDX-License-Identifier: Apache-2.0 OR LGPL-2.1-or-later

pguyot · 2025-08-08T16:22:45Z

src/platforms/esp32/components/avm_sys/platform_nifs.c

 }
 #endif

+static term nif_esp_gpio_wakeup_enable(Context *ctx, int argc, term argv[])


I would call this gpio:wakeup_enable/2 to match with the esp-idf function name.

this means we are leaking more ESP32 specific stuff into GPIO module. I think they can be made somehow generic, but I'm not sure how.

src/platforms/esp32/components/avm_sys/platform_nifs.c

bettio · 2025-08-10T10:30:14Z

There is something that I'd like to here the opinion about:

Should we use the avm_pubsub for pushing power manager events when returning from sleep?
Such as different 3rd party drivers might need to check if any IRQ pin has been raised during sleep, or any other process might need to know that everything was suspend for a certain amount of time.
So we have either 2 options: leave the caller handle this when returning from sleep, or standardizing some kind of mechanism for informing drivers and anything else that there was a power management related event.

pguyot · 2025-08-10T12:26:11Z

There is something that I'd like to here the opinion about:

Should we use the avm_pubsub for pushing power manager events when returning from sleep? Such as different 3rd party drivers might need to check if any IRQ pin has been raised during sleep, or any other process might need to know that everything was suspend for a certain amount of time. So we have either 2 options: leave the caller handle this when returning from sleep, or standardizing some kind of mechanism for informing drivers and anything else that there was a power management related event.

We could use monitor/2 to get the event.

BEAM documentation reads:

The monitor functionality is expected to be extended. That is, other Types and Items are expected to be supported in a future release.

UncleGrumpy · 2025-08-11T16:55:15Z

We could use monitor/2 to get the event.

This is an interesting suggestion, and might be useful to expose an API for pushing other “monitored” events, like acquiring or loosing a network connection.

I think some standardized notification system would be good, but it should be opt in, so extra resources are not consumed if they are not used.

petermm · 2026-01-11T16:19:09Z

lgtm, there is also some docs over here:

"Usage of light sleep is untested, and no support for controlling light sleep is currently implemented. Reach out if you do any experiments and measurements."

AtomVM/doc/src/build-instructions.md

Line 384 in 6330d9f

#### Sleep mode - Light sleep

that needs updating

src/libAtomVM/jit.c

+    if (n <= 64) {
+        union maybe_unsigned_int64 value;
+        bool status = bitstring_extract_integer(
+            ((term) bin_ptr) | TERM_PRIMARY_BOXED, offset, n, bs_flags, &value);


src/libAtomVM/jit.c

+    bool status;
+    switch (n) {
+        case 16:
+            status = bitstring_extract_f16(((term) bin_ptr) | TERM_PRIMARY_BOXED, offset, n, bs_flags, &value);


src/libAtomVM/jit.c

+            status = bitstring_extract_f16(((term) bin_ptr) | TERM_PRIMARY_BOXED, offset, n, bs_flags, &value);
+            break;
+        case 32:
+            status = bitstring_extract_f32(((term) bin_ptr) | TERM_PRIMARY_BOXED, offset, n, bs_flags, &value);


src/libAtomVM/jit.c

+            status = bitstring_extract_f32(((term) bin_ptr) | TERM_PRIMARY_BOXED, offset, n, bs_flags, &value);
+            break;
+        case 64:
+            status = bitstring_extract_f64(((term) bin_ptr) | TERM_PRIMARY_BOXED, offset, n, bs_flags, &value);


petermm · 2026-01-24T10:47:46Z

doc/src/build-instructions.md

-#### Sleep mode - Light sleep
-
-Usage of light sleep is untested, and no support for controlling light sleep is currently implemented. Reach out if you do any experiments and measurements.
+Light sleep is supported as well and can be enabled on ESP32 using the releated functions. When using light sleep memory is retained, and execution is resumed as soon as wakeup is triggered from a wakeup source.


releated -> related

Allow putting ESP32 to light sleep, and wake it up using a GPIO or a timer. Signed-off-by: Davide Bettio <davide@uninstall.it>

petermm

LGTM - we just need to remember build_instructions.md when forwarding it to main..

Merge ESP32 light sleep support (#1789) from release-0.6 branch.

After atomvm#1789 (and the subsequent forward port from release-0.6), light sleep has been introduced in main. Update newer documentation accordingly. Signed-off-by: Davide Bettio <davide@uninstall.it>

After atomvm#1789 (and the subsequent forward port from release-0.6), light sleep has been merged in main. Update newer documentation accordingly. Signed-off-by: Davide Bettio <davide@uninstall.it>

bettio force-pushed the add-support-to-esp32-light-sleep branch from 778ca20 to 0cb4308 Compare August 8, 2025 14:39

pguyot reviewed Aug 8, 2025

View reviewed changes

bettio force-pushed the add-support-to-esp32-light-sleep branch from 0cb4308 to 4d62044 Compare August 10, 2025 15:01

bettio force-pushed the add-support-to-esp32-light-sleep branch from 4d62044 to a07cef1 Compare January 22, 2026 14:06

github-advanced-security bot found potential problems Jan 22, 2026

View reviewed changes

petermm reviewed Jan 24, 2026

View reviewed changes

bettio force-pushed the add-support-to-esp32-light-sleep branch from a07cef1 to 28023c0 Compare January 24, 2026 13:57

ESP32: add support to light sleep

183c398

Allow putting ESP32 to light sleep, and wake it up using a GPIO or a timer. Signed-off-by: Davide Bettio <davide@uninstall.it>

bettio force-pushed the add-support-to-esp32-light-sleep branch from 28023c0 to 183c398 Compare January 24, 2026 14:23

petermm approved these changes Jan 24, 2026

View reviewed changes

bettio merged commit bcb9d81 into atomvm:release-0.6 Jan 25, 2026
87 of 105 checks passed

bettio added a commit that referenced this pull request Feb 1, 2026

Forward port changes from v0.6 release branch

07e37ae

Merge ESP32 light sleep support (#1789) from release-0.6 branch.

bettio mentioned this pull request Feb 5, 2026

Update documentation with info about light sleep #2088

Open

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

ESP32: add support to light sleep#1789

ESP32: add support to light sleep#1789
bettio merged 1 commit intoatomvm:release-0.6from
bettio:add-support-to-esp32-light-sleep

bettio commented Aug 8, 2025 •

edited

Loading

Uh oh!

pguyot Aug 8, 2025

Uh oh!

bettio Aug 10, 2025

Uh oh!

bettio Jan 24, 2026

Uh oh!

Uh oh!

bettio commented Aug 10, 2025 •

edited

Loading

Uh oh!

pguyot commented Aug 10, 2025 •

edited

Loading

Uh oh!

UncleGrumpy commented Aug 11, 2025

Uh oh!

petermm commented Jan 11, 2026

Uh oh!

Check failure

Check failure

Check failure

Check failure

petermm Jan 24, 2026

Uh oh!

petermm left a comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

Conversation

bettio commented Aug 8, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

pguyot Aug 8, 2025

Choose a reason for hiding this comment

Uh oh!

bettio Aug 10, 2025

Choose a reason for hiding this comment

Uh oh!

bettio Jan 24, 2026

Choose a reason for hiding this comment

Uh oh!

Uh oh!

bettio commented Aug 10, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

pguyot commented Aug 10, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

UncleGrumpy commented Aug 11, 2025

Uh oh!

petermm commented Jan 11, 2026

Uh oh!

Check failure

Check failure

Check failure

Check failure

petermm Jan 24, 2026

Choose a reason for hiding this comment

Uh oh!

petermm left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

bettio commented Aug 8, 2025 •

edited

Loading

bettio commented Aug 10, 2025 •

edited

Loading

pguyot commented Aug 10, 2025 •

edited

Loading