counter.py

"""
Very basic example showing data exchange main CPU <--> ULP coprocessor.

To show that the ULP is doing something, it just increments the value <data>.
It does that once per ulp timer wakeup (and then the ULP halts until it gets
waked up via the timer again).

The timer is set to a rather long period, so you can watch the data value
incrementing (see loop at the end).
"""

from esp32 import ULP
from machine import mem32

from esp32_ulp import src_to_binary

source = """\
data:       .long 0

entry:      move r3, data    # load address of data into r3
            ld r2, r3, 0     # load data contents ([r3+0]) into r2
            add r2, r2, 1    # increment r2
            st r2, r3, 0     # store r2 contents into data ([r3+0])

            halt             # halt ULP co-prozessor (until it gets waked up again)
"""

binary = src_to_binary(source, cpu="esp32")  # cpu is esp32 or esp32s2

load_addr, entry_addr = 0, 4

ULP_MEM_BASE = 0x50000000
ULP_DATA_MASK = 0xffff  # ULP data is only in lower 16 bits

ulp = ULP()
ulp.set_wakeup_period(0, 50000)  # use timer0, wakeup after 50.000 cycles
ulp.load_binary(load_addr, binary)

mem32[ULP_MEM_BASE + load_addr] = 0x1000
ulp.run(entry_addr)

while True:
    print(hex(mem32[ULP_MEM_BASE + load_addr] & ULP_DATA_MASK))