Espressif ESP32-S2 User Manual

Chapter 4. API Guides
Some existing macros are defined in soc/soc_ulp.h header file. These macros allow access to the fields of
peripheral registers by their names. Peripheral registers names which can be used with these macros are the ones
defined in soc/rtc_cntl_reg.h, soc/rtc_io_reg.h, soc/sens_reg.h, and soc/rtc_i2c_reg.
h.
READ_RTC_REG(rtc_reg, low_bit, bit_width) Read up to 16 bits from rtc_reg[low_bit + bit_width - 1 :
low_bit] into R0. For example:
#include "soc/soc_ulp.h"
#include "soc/rtc_cntl_reg.h"
/* Read 16 lower bits of RTC_CNTL_TIME0_REG into R0 */
READ_RTC_REG(RTC_CNTL_TIME0_REG, 0, 16)
READ_RTC_FIELD(rtc_reg, field) Read from a field in rtc_reg into R0, up to 16 bits. For example:
#include "soc/soc_ulp.h"
#include "soc/sens_reg.h"
/* Read 8-bit SENS_TSENS_OUT field of SENS_SAR_SLAVE_ADDR3_REG into R0 */
READ_RTC_FIELD(SENS_SAR_SLAVE_ADDR3_REG, SENS_TSENS_OUT)
WRITE_RTC_REG(rtc_reg, low_bit, bit_width, value) Write immediate value into rtc_reg[low_bit + bit_width
- 1 : low_bit], bit_width <= 8. For example:
#include "soc/soc_ulp.h"
#include "soc/rtc_io_reg.h"
/* Set BIT(2) of RTC_GPIO_OUT_DATA_W1TS field in RTC_GPIO_OUT_W1TS_REG */
WRITE_RTC_REG(RTC_GPIO_OUT_W1TS_REG, RTC_GPIO_OUT_DATA_W1TS_S + 2, 1, 1)
WRITE_RTC_FIELD(rtc_reg, field, value) Write immediate value into a field in rtc_reg, up to 8 bits. For ex-
ample:
#include "soc/soc_ulp.h"
#include "soc/rtc_cntl_reg.h"
/* Set RTC_CNTL_ULP_CP_SLP_TIMER_EN field of RTC_CNTL_STATE0_REG to 0 */
WRITE_RTC_FIELD(RTC_CNTL_STATE0_REG, RTC_CNTL_ULP_CP_SLP_TIMER_EN, 0)
4.28.2 Programming ULP coprocessor using C macros (legacy)
In addition to the existing binutils port for the ESP32 ULP coprocessor, it is possible to generate programs for the
ULP by embedding assembly-like macros into an ESP32 application. Here is an example how this can be done:
const ulp_insn_t program[] = {
I_MOVI(R3, 16), // R3 <- 16
I_LD(R0, R3, 0), // R0 <- RTC_SLOW_MEM[R3 + 0]
I_LD(R1, R3, 1), // R1 <- RTC_SLOW_MEM[R3 + 1]
I_ADDR(R2, R0, R1), // R2 <- R0 + R1
I_ST(R2, R3, 2), // R2 -> RTC_SLOW_MEM[R2 + 2]
I_HALT()
};
size_t load_addr = 0;
size_t size = sizeof(program)/sizeof(ulp_insn_t);
ulp_process_macros_and_load(load_addr, program, &size);
ulp_run(load_addr);
The program array is an array of ulp_insn_t, i.e. ULP coprocessor instructions. Each I_XXX preprocessor
define translates into a single 32-bit instruction. Arguments of these preprocessor defines can be register numbers
(R0 —R3) and literal constants. See ULP coprocessor instruction defines section for descriptions of instructions and
arguments they take.
Espressif Systems 1491
Submit Document Feedback
Release v4.4

Espressif ESP32-S2 Specifications

General

Brand	Espressif
Model	ESP32-S2
Category	Single board computers
Language	English