Repository navigation
M5ToughC5: getWakeSource() always returns 0 #431
Description
Observed:
On M5ToughC5 the wake source value returned for any wake source (power button, timer, ...) is always 0.
Expected:
The reported wake source should match the actual wake source as defined in m5pm1_wake_src_t in file M5PM1.h.
Code:
#include <M5Unified.h>
#include <M5PM1.h>
M5PM1 pm1;
void setup(void)
{
uint8_t wake_source = 255;
M5.begin();
pm1.begin(&M5.In_I2C, M5PM1_DEFAULT_ADDR, M5PM1_I2C_FREQ_400K);
pm1.getWakeSource(&wake_source, M5PM1_CLEAN_ALL);
M5.Display.setTextSize(2);
M5.Display.printf("Wake Source: %d\n", wake_source);
}
void loop(void)
{
M5.update();
if(!M5.Touch.getCount()) return;
M5.Display.println("Power ON after 5s");
delay(1000);
pm1.timerSet(5, M5PM1_TIM_ACTION_POWERON);
pm1.shutdown();
}
Libraries used:
M5Unified: 0.2.29
M5GFX: 0.2.36
M5PM1: 1.0.7
Thanks
Felix
Activity
ainyan03 commentedon Nov 5, 2026
Thank you for the report. The fix is merged into the
developbranch and will be part of the next M5Unified release. It is not in a release yet.What to do after updating
Read the wake source through M5Unified instead of the M5PM1 library:
The bits are the same as
m5pm1_wake_src_t, for example0x01for the timer and0x04for the power button. It returns 0 when no reason was recorded, for example after a reset.Why the value was 0
M5.begin()has to clear the PM1WAKE_SRCregister on ToughC5, because the PM1 IRQ output stays low until it is cleared. Anything that reads the register afterwards gets 0.M5Unified now keeps the value before clearing it, and
getWakeSource()above returns that kept value. The register itself is still cleared, so this behavior does not change.About
M5PM1.hM5PM1.hbelongs to the separate M5PM1 library, which is not part of M5Unified. M5Unified does not use it, sopm1.getWakeSource()from that library still reads the register directly and still returns 0 afterM5.begin(). Reading it beforeM5.begin()is not something M5Unified supports.Details are in #432. The M-Bus pins of ToughC5 were also added to
getPin()there.felmue commentedon Nov 6, 2026
Hello @ainyan03
thank you for the quick fix and the detailed explanation. I appreciate it.
I tested and verified the fix using M5Unified 0.3.0 (alongside M5GFX 0.3.0) and I can confirm that reading the wake source via
M5.Power.M5pm1.getWakeSource();reports the correct wake source.Thanks
Felix