|
| 1 | +# |
| 2 | +# This file is part of the micropython-esp32-ulp project, |
| 3 | +# https://github.com/micropython/micropython-esp32-ulp |
| 4 | +# |
| 5 | +# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file. |
| 6 | +# SPDX-License-Identifier: MIT |
| 7 | + |
| 8 | +""" |
| 9 | +Example for: ESP32-S2 Wemos mini development board V1.0.0 with led on pin 15 |
| 10 | +
|
| 11 | +This example creates a PWM-like dimming effect using self-modifying ULP code. |
| 12 | +The ULP program rewrites the `WAIT` instructions to control on/off LED durations, |
| 13 | +simulating a variable duty cycle. |
| 14 | +
|
| 15 | +Note: |
| 16 | +The `WAIT` instruction uses an immediate operand (fixed value) for delay cycles. However, we can change the lower half of memory |
| 17 | +to modify these values at runtime, simulating variable wait times via registers. |
| 18 | +""" |
| 19 | + |
| 20 | +fromesp32importULP |
| 21 | +frommachineimportmem32 |
| 22 | +fromesp32_ulpimportsrc_to_binary |
| 23 | +fromtimeimportsleep |
| 24 | + |
| 25 | +source="""\ |
| 26 | +# constants from: |
| 27 | +# https://github.com/espressif/esp-idf/blob/v5.0.2/components/soc/esp32s2/include/soc/reg_base.h |
| 28 | +#define DR_REG_RTCIO_BASE 0x3f408400 |
| 29 | +
|
| 30 | +# constants from: |
| 31 | +# https://github.com/espressif/esp-idf/blob/v5.0.2/components/soc/esp32s2/include/soc/rtc_io_reg.h |
| 32 | +#define RTC_IO_XTAL_32P_PAD_REG (DR_REG_RTCIO_BASE + 0xC0) |
| 33 | +#define RTC_IO_X32P_MUX_SEL_M (BIT(19)) |
| 34 | +#define RTC_GPIO_OUT_REG (DR_REG_RTCIO_BASE + 0x0) |
| 35 | +#define RTC_GPIO_ENABLE_REG (DR_REG_RTCIO_BASE + 0xc) |
| 36 | +#define RTC_GPIO_ENABLE_S 10 |
| 37 | +#define RTC_GPIO_OUT_DATA_S 10 |
| 38 | +
|
| 39 | +# constants from: |
| 40 | +# https://github.com/espressif/esp-idf/blob/v5.0.2/components/soc/esp32s2/include/soc/rtc_io_channel.h |
| 41 | +#define RTCIO_GPIO15_CHANNEL 15 |
| 42 | +
|
| 43 | +.global entry |
| 44 | +program_init: |
| 45 | + # connect GPIO to ULP (0: GPIO connected to digital GPIO module, 1: GPIO connected to analog RTC module) |
| 46 | + WRITE_RTC_REG(RTC_IO_XTAL_32P_PAD_REG, RTC_IO_X32P_MUX_SEL_M, 1, 1); |
| 47 | +
|
| 48 | + # enable GPIO as output, not input (this also enables a pull-down by default) |
| 49 | + WRITE_RTC_REG(RTC_GPIO_ENABLE_REG, RTC_GPIO_ENABLE_S + RTCIO_GPIO15_CHANNEL, 1, 1) |
| 50 | +
|
| 51 | +set_waits: add r0, r0, 0xFF # Increase r0 (delay time) |
| 52 | + move r3, wait_off |
| 53 | + st r0, r3, 0 # Overwrite wait_off with new delay value |
| 54 | +
|
| 55 | + move r2, 0xFFFF |
| 56 | + sub r1, r2, r0 # Calculate complementary delay time |
| 57 | + move r3, wait_on |
| 58 | + st r1, r3, 0 # Overwrite wait_on with new value |
| 59 | +
|
| 60 | + WRITE_RTC_REG(RTC_GPIO_OUT_REG, RTC_GPIO_OUT_DATA_S + RTCIO_GPIO15_CHANNEL, 1, 0) # turn off led |
| 61 | +wait_off: wait 0 # Placeholder; value overwritten dynamically |
| 62 | + WRITE_RTC_REG(RTC_GPIO_OUT_REG, RTC_GPIO_OUT_DATA_S + RTCIO_GPIO15_CHANNEL, 1, 1) # turn on led |
| 63 | +wait_on: wait 0 # Placeholder; value overwritten dynamically |
| 64 | +
|
| 65 | +jump set_waits # Loop program |
| 66 | +
|
| 67 | +""" |
| 68 | + |
| 69 | +binary=src_to_binary(source,cpu="esp32s2")# cpu is esp32 or esp32s2 |
| 70 | + |
| 71 | +load_addr,entry_addr=0,0 |
| 72 | + |
| 73 | +ULP_MEM_BASE=0x50000000 |
| 74 | + |
| 75 | +ulp=ULP() |
| 76 | +ulp.load_binary(load_addr,binary) |
| 77 | + |
| 78 | +ulp.run(entry_addr) |
| 79 | + |
| 80 | +whileTrue: |
| 81 | +print(hex(mem32[ULP_MEM_BASE+40]))# show that the WAIT cycles are changing |
| 82 | +sleep(0.5) |