I've started a personal project a few days ago and I'm stuck on it. The idea is to output PWM on pin 8 (GPIO8) of a ESP32-C3 using LEDC peripheral on an ESP32-C3 using assembly language (RISC-V) with ESP-IDF. I've started by configuring GPIO, LEDC and enabling LEDC_CLK (according to the ESP32-C3 technical documentation) but no output have been observed.
The fisrt thing I did was to use simple output (using GPIO_OUTPUT_REG) and it worked ! Then I changed the GPIO Matrix output signal for a given pin by using the function ledc_ls_sig_out3. At this point nothing worked correctly : for instance changing the value of LEDC_IDLE_LV_CH (default output of LEDC) did not impact the output.
I put my code on my GitHub : https://github.com/LeoDupuy02/simple_ledc_pwm.git
I would like to know if there is specific registers to program to enable LEDC or to let LEDC access some memory or if the project is a bit too tough.. Thank you !
Assembly code :
init_pwm :
addi sp, sp, -4
sw ra, 0(sp)
# -----------------------------------------------------------------------------
#### Base : 0x600C_0000 - System registers
# SYSTEM_PERIP_RST_EN0_REG (0x0018) -> 0x0800 : RESET SYS_LEDC_CLK
li a2, 0x600C0018
li t5, 0x00000800
lw t1, 0(a2)
or t1, t1, t5
sw t1, 0(a2)
li a2, 0x600C0018
li t5, 0x00000000
lw t1, 0(a2)
and t1, t1, t5
sw t1, 0(a2)
# SYSTEM_PERIP_CLK_EN0_REG (0x0010) -> 0x0800 : enable SYS_LEDC_CLK
li a2, 0x600C0010
li t6, 0x00000800
lw t1, 0(a2)
or t1, t1, t5
sw t1, 0(a2)
# SYSTEM_SYSCLK_CONF_REG (0x0058) -> 0x0400 : PLL as SOC CLK
#li a2, 0x600C0058
#li t5, 0x00400
#lw t1, 0(a2)
#or t1, t1, t5
#sw t1, 0(a2)
# SYSTEM_CLOCK_GATE_REG (0x0054) -> ori 0x0001
# -------------------------------------------------------------
# Base LEDC_PWM : 0x6001_9000
# Register : LEDC_CONF_REG : 0x00D0 (general) : APB_CLK as LEDC Timer
li t5, 0x80000001
li a2, 0x600190D0
lw t1, 0(a2)
or t1, t1, t5
sw t1, 0(a2)
# Register : LEDC_TIMER3_CONF_REG : 0x00B8
li t5, 0x0000F906
li a2, 0x600190B8
lw t1, 0(a2)
or t1, t1, t5
sw t1, 0(a2)
# Register : LEDC_CH3_HPOINT_REG : 0x00040
li t5, 0x0000010
li a2, 0x60019040
lw t1, 0(a2)
or t1, t1, t5
sw t1, 0(a2)
# Register : LEDC_CH3_DUTY_REG : 0x0044
li t5, 0x00000080
li a2, 0x60019044
lw t1, 0(a2)
or t1, t1, t5
sw t1, 0(a2)
# Register : LEDC_CH3_CONF0_REG : 0x003C
li t5, 0x0000000f
li a2, 0x6001903C
lw t1, 0(a2)
or t1, t1, t5
sw t1, 0(a2)
# Register : LEDC_CH3_CONF1_REG : 0x0048
li t5, 0x00000000
li a2, 0x60019048
lw t1, 0(a2)
or t1, t1, t5
sw t1, 0(a2)
# ---- UPDATE -----
# Register : LEDC_CH3_CONF0_REG : 0x0000 (register 0)
li t5, 0x00000010
li a2, 0x6001903C
lw t1, 0(a2)
or t1, t1, t5
sw t1, 0(a2)
# Register : LEDC_TIMER3_CONF_REG : 0x00B8
li t5, 0x02000000
li a2, 0x600190B8
lw t1, 0(a2)
or t1, t1, t5
sw t1, 0(a2)
# ----------------------------------------------------------------------
# Base GPIO : 0x6000_4000
# Register : GPIO_FUNC48_IN_SEL_CFG_REG (n: 0-127) (0x0154+4*n) : bit 7 to 1
#li t5, 0x0040
#li a2, 0x60004214
#lw t1, 0(a2)
#or t1, t1, t5
#sw t1, 0(a2)
# Register : GPIO_FUNC8_OUT_SEL_CFG_REG (n: 0-21) (0x0554+4*n) : valeur sur 46 (ledc_ls_sig_out1 ) + 9ème bit sur 0 (to enable peripheral output)
li a2, 0x60004574
li t5, 0xfffff800
li t6, 0x00000030
lw t1, 0(a2)
and t1, t1, t5
or t1, t1, t6
sw t1, 0(a2)
# Register : IO_MUX_GPIO8_REG (0x0004+4*8) : CONFIG MUX : 0001010010100100
li t5, 0x1000
li t6, 0xfffff000
li a2, 0x60009024
lw t1, 0(a2)
or t1, t1, t5
and t1, t1, t6
sw t1, 0(a2)
# Register : GPIO_ENABLE_W1TC_REG (0x0028) : Clear ENABLE Reg
# Register : GPIO_ENABLE_W1TS_REG (0x0024) : SET ENABLE
li t5, 0x0100
li a2, 0x60004024
lw t1, 0(a2)
or t1, t1, t5
sw t1, 0(a2)
# Register : GPIO_OUT_W1TS_REG (0x0008)
li t5, 0x0100
li a2, 0x60004000
lw t1, 0(a2)
or t1, t1, t5
sw t1, 0(a2)
# Register : GPIO_OUT_W1TC_REG (0x000C)
addi sp, sp, 4
jalr ra