# # Example of putting the main processor to sleep then waking it up # via the ULP after a while # from esp32 import ULP from machine import mem32 import machine from esp32_ulp import src_to_binary source = """\ #define RTC_CNTL_LOW_POWER_ST_REG 0x3FF480c0 #define RTC_CNTL_RDY_FOR_WAKEUP BIT(19)  entry:  MOVE r0, 2000  loop:  WAIT 40000 // at 8 MHz this is 5 msec, if we do this 1000 times that's 5 seconds  SUB r0, r0, 1  jump is_rdy_for_wakeup, eq  jump loop   is_rdy_for_wakeup: // Read RTC_CNTL_RDY_FOR_WAKEUP bit # # This test was described in https://github.com/espressif/esp-idf/issues/8341 # See reference manual 31.19. # # The main issue with this is that it will hang if the main CPU wasn't in deep sleep. #  READ_RTC_FIELD(RTC_CNTL_LOW_POWER_ST_REG, RTC_CNTL_RDY_FOR_WAKEUP)  AND r0, r0, 1  JUMP is_rdy_for_wakeup, eq // Retry until the bit is set   WAKE // Trigger wake up  HALT // Stop the ULP program """ # # Compile the ULP code # binary = src_to_binary(source) load_addr, entry_addr = 0, 0 ULP_MEM_BASE = 0x50000000 ULP_DATA_MASK = 0xffff # ULP data is only in lower 16 bits ulp = ULP() ulp.load_binary(load_addr, binary) # # The ULP starts out asleep (halted), so set a timer to wake it # up the first time. # # ulp.set_wakeup_period(0, 50000) # use timer0, wakeup after 50.000 cycles mem32[ULP_MEM_BASE + load_addr] = 0x1000 ulp.run(entry_addr) print("going to sleep") # I think this should enable ULP wakeup mem32[ 0x3ff48038 ] = 0x200 << 10 machine.deepsleep() # # We won't ever reach this, because WAKE is going to cause the main # processor to reset and start over at the beginning. # print("I am awake again")