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Derek Jamison edited this page Sep 5, 2024 · 2 revisions

When you use certain Flipper Zero features, the code will end up calling furi_hal_bus_enable passing a bus to reserve. On debug builds of the firmware there is a furi_check that makes sure no other code has already requested that bus. If the resource is already in use, you will get a "Flipper crashed and was rebooted - furi_check failed" message if you are on a [Release] firmware (on a [Debug] firmware the Flipper may appear frozen - waiting for the debugger to attach - or until you press BACK+LEFT to reboot.)

NOTE: furi_check can happen for MANY reasons, but one reason is that furi_hal_bus_enable got called on the same bus twice.

furi_crash

The best way to tell the cause of the crash, is to attach a debugger and reproduce the crash. And then click on the second function in the call stack.

image

The .\targets\f7\furi_hal\furi_hal_bus.h file lists the various choices for FuriHalBus. Below is a table of common resources that use common timers that you may be using in your code.

Feature Bus
iButton FuriHalBusTIM1
Infrared (RX) FuriHalBusTIM2
Infrared (TX) FuriHalBusTIM1
PWM (pin A7) FuriHalBusTIM1
PWM (pin A4) FuriHalBusLPTIM2
LF-RFID (READ) FuriHalBusTIM1 & FuriHalBusTIM2
LF-RFID (Emulate) FuriHalBusTIM2
NFC FuriHalBusTIM1 & FuriHalBusTIM17
SUB-GHZ (RX) FuriHalBusTIM2
SUB-GHZ (TX) FuriHalBusTIM2

There are many more bus that may be in use, but I found this is a common one. You should search the implementation files for furi_hal_bus_enable to understand which resources it uses. Typically the implementation files that use the bus are in ./targets/f7/furi_hal/furi_hal_<feature-name>.c. Sometimes they use a name that is redefined elsewhere in the file (for example INFRARED_RX_TIMER_BUS is a #define for FuriHalBusTIM2.)

// Relevant #define from Official firmware (Sept 5, 2024)
IBUTTON: #define FURI_HAL_IBUTTON_TIMER_BUS FuriHalBusTIM1

INFRARED (RX): #define INFRARED_RX_TIMER_BUS  FuriHalBusTIM2
INFRARED (TX): #define INFRARED_DMA_TIMER_BUS FuriHalBusTIM1

PWM (PA7) :  furi_hal_bus_enable(FuriHalBusTIM1); 
PWM (PA4): furi_hal_bus_enable(FuriHalBusLPTIM2);

LF-RFID (READ): #define FURI_HAL_RFID_READ_TIMER_BUS FuriHalBusTIM1
                #define RFID_CAPTURE_TIM_BUS FuriHalBusTIM2
LF-RFID (EMULATE): #define FURI_HAL_RFID_EMULATE_TIMER_BUS FuriHalBusTIM2
                #define FURI_HAL_RFID_FIELD_COUNTER_TIMER_BUS FuriHalBusTIM2
LF-RFID (FIELD PRESENCE DETECT): #define FURI_HAL_RFID_FIELD_TIMEOUT_TIMER_BUS FuriHalBusTIM1

NFC: [FuriHalNfcTimerFwt] = {.bus = FuriHalBusTIM1,}
NFC: [FuriHalNfcTimerBlockTx] = {.bus = FuriHalBusTIM17,}

SUB-GHz (RX): furi_hal_bus_enable(FuriHalBusTIM2);
SUB-GHz (TX): furi_hal_bus_enable(FuriHalBusTIM2);
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