"ledc_get_duty(): channel argument is invalid" error for more than 8 PWM channels on ESP32 with ledcAttach

[diyelectromusic]

Board

ESP32 WROOM DA

Device Description

Commonly available ESP32 third party DevKit

Hardware Configuration

None

Version

latest development Release Candidate (RC-X)

IDE Name

Arduino IDE

Operating System

Windows 10

Flash frequency

80MHz

PSRAM enabled

yes

Upload speed

115200

Description

Attempting to configure more than 8 PWM channels using ledcAttach() results in the error "ledc: ledc_get_duty(736): channel argument is invalid" for all channels greater than 8.

I believe this might be due to the fact that in the ledcAttachChannel() function, the "channel" parameter is passed directly into ledc_get_duty() whereas in other calls to ledc_get_duty() the required parameter is "channel % 8".

The call fails the check in ledc_get_duty() against LEDC_CHANNEL_MAX which is part of the enum ledc_channel_t defined in components/hal/include/hal/ledc_types.h in the ESPIDF and presumably ends up with the value 8 (given there are 8 previous entries in the enum definition).

Note: I don't believe this stops the channel from being configured, as the code follows through regardless - it is just additional erroneous error messages, but I don't know the impact of "duty" being invalid when next passed into ledc_channel_config() in the ledcAttachChannel() function.

Sketch

int pwmpins[10] = {15,2,4,16,17,5,18,19,21,22};

void setup() {
  Serial.begin(115200);
  for (int i=0; i< 10; i++) {
    Serial.print("Attaching ");
    Serial.println(i);
    ledcAttach(pwmpins[i], 5000, 8);
  }
}

void loop() {
}

### Debug Message

```plain
ets Jul 29 2019 12:21:46

rst:0x1 (POWERON_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:1
load:0x3fff0030,len:1448
load:0x40078000,len:14844
ho 0 tail 12 room 4
load:0x40080400,len:4
load:0x40080404,len:3356
entry 0x4008059c
Attaching 0
[    10][I][esp32-hal-ledc.c:117] ledcAttachChannel(): LEDC attached to pin 15 (channel 0, resolution 8)
Attaching 1
[    21][I][esp32-hal-ledc.c:117] ledcAttachChannel(): LEDC attached to pin 2 (channel 1, resolution 8)
Attaching 2
[    31][I][esp32-hal-ledc.c:117] ledcAttachChannel(): LEDC attached to pin 4 (channel 2, resolution 8)
Attaching 3
[    41][I][esp32-hal-ledc.c:117] ledcAttachChannel(): LEDC attached to pin 16 (channel 3, resolution 8)
Attaching 4
[    51][I][esp32-hal-ledc.c:117] ledcAttachChannel(): LEDC attached to pin 17 (channel 4, resolution 8)
Attaching 5
[    62][I][esp32-hal-ledc.c:117] ledcAttachChannel(): LEDC attached to pin 5 (channel 5, resolution 8)
Attaching 6
[    72][I][esp32-hal-ledc.c:117] ledcAttachChannel(): LEDC attached to pin 18 (channel 6, resolution 8)
Attaching 7
[    82][I][esp32-hal-ledc.c:117] ledcAttachChannel(): LEDC attached to pin 19 (channel 7, resolution 8)
Attaching 8
E (91) ledc: ledc_get_duty(736): channel argument is invalid
[    93][I][esp32-hal-ledc.c:117] ledcAttachChannel(): LEDC attached to pin 21 (channel 8, resolution 8)
Attaching 9
E (107) ledc: ledc_get_duty(736): channel argument is invalid
[   109][I][esp32-hal-ledc.c:117] ledcAttachChannel(): LEDC attached to pin 22 (channel 9, resolution 8)
  Allocated Bytes   :    22972 B (  22.4 KB)
  Minimum Free Bytes:   351708 B ( 343.5 KB)
  Largest Free Block:   118772 B ( 116.0 KB)
------------------------------------------
Flash Info:
------------------------------------------
  Chip Size         :  4194304 B (4 MB)
  Block Size        :    65536 B (  64.0 KB)
  Sector Size       :     4096 B (   4.0 KB)
  Page Size         :      256 B (   0.2 KB)
  Bus Speed         : 80 MHz
  Bus Mode          : QIO
------------------------------------------
Partitions Info:
------------------------------------------
                nvs : addr: 0x00009000, size:    20.0 KB, type: DATA, subtype: NVS
            otadata : addr: 0x0000E000, size:     8.0 KB, type: DATA, subtype: OTA
               app0 : addr: 0x00010000, size:  1280.0 KB, type:  APP, subtype: OTA_0
               app1 : addr: 0x00150000, size:  1280.0 KB, type:  APP, subtype: OTA_1
             spiffs : addr: 0x00290000, size:  1408.0 KB, type: DATA, subtype: SPIFFS
           coredump : addr: 0x003F0000, size:    64.0 KB, type: DATA, subtype: COREDUMP
------------------------------------------
Software Info:
------------------------------------------
  Compile Date/Time : May 14 2024 20:46:54
  Compile Host OS   : windows
  ESP-IDF Version   : v5.1.4-51-g442a798083-dirty
  Arduino Version   : 3.0.0
------------------------------------------
Board Info:
------------------------------------------
  Arduino Board     : ESP32_WROOM_DA
  Arduino Variant   : esp32da
  Arduino FQBN      : esp32:esp32:esp32da:PartitionScheme=default,CPUFreq=240,FlashMode=qio,FlashFreq=80,FlashSize=4M,UploadSpeed=921600,LoopCore=1,EventsCore=1,DebugLevel=debug,EraseFlash=none
============ Before Setup End ============
Attaching 0
[   502][I][esp32-hal-ledc.c:117] ledcAttachChannel(): LEDC attached to pin 15 (channel 0, resolution 8)
Attaching 1
[   512][I][esp32-hal-ledc.c:117] ledcAttachChannel(): LEDC attached to pin 2 (channel 1, resolution 8)
Attaching 2
[   523][I][esp32-hal-ledc.c:117] ledcAttachChannel(): LEDC attached to pin 4 (channel 2, resolution 8)
Attaching 3
[   533][I][esp32-hal-ledc.c:117] ledcAttachChannel(): LEDC attached to pin 16 (channel 3, resolution 8)
Attaching 4
[   543][I][esp32-hal-ledc.c:117] ledcAttachChannel(): LEDC attached to pin 17 (channel 4, resolution 8)
Attaching 5
[   554][I][esp32-hal-ledc.c:117] ledcAttachChannel(): LEDC attached to pin 5 (channel 5, resolution 8)
Attaching 6
[   564][I][esp32-hal-ledc.c:117] ledcAttachChannel(): LEDC attached to pin 18 (channel 6, resolution 8)
Attaching 7
[   574][I][esp32-hal-ledc.c:117] ledcAttachChannel(): LEDC attached to pin 19 (channel 7, resolution 8)
Attaching 8
E (583) ledc: ledc_get_duty(736): channel argument is invalid
[   585][I][esp32-hal-ledc.c:117] ledcAttachChannel(): LEDC attached to pin 21 (channel 8, resolution 8)
Attaching 9
E (599) ledc: ledc_get_duty(736): channel argument is invalid
[   600][I][esp32-hal-ledc.c:117] ledcAttachChannel(): LEDC attached to pin 22 (channel 9, resolution 8)
=========== After Setup Start ============
INTERNAL Memory Info:
------------------------------------------
  Total Size        :   387244 B ( 378.2 KB)
  Free Bytes        :   354692 B ( 346.4 KB)
  Allocated Bytes   :    24988 B (  24.4 KB)
  Minimum Free Bytes:   349056 B ( 340.9 KB)
  Largest Free Block:   118772 B ( 116.0 KB)
------------------------------------------
GPIO Info:
------------------------------------------
  GPIO : BUS_TYPE[bus/unit][chan]
  --------------------------------------  
     1 : UART_TX[0]
     2 : LEDC[0][1]
     3 : UART_RX[0]
     4 : LEDC[0][2]
     5 : LEDC[0][5]
    15 : LEDC[0][0]
    16 : LEDC[0][3]
    17 : LEDC[0][4]
    18 : LEDC[0][6]
    19 : LEDC[0][7]
    21 : LEDC[1][8]
    22 : LEDC[1][9]
============ After Setup End =============

Other Steps to Reproduce

No response

I have checked existing issues, online documentation and the Troubleshooting Guide

• I confirm I have checked existing issues, online documentation and Troubleshooting guide.

[P-R-O-C-H-Y]

@diyelectromusic Thank you for reporting the issue. I have opened a PR with a fix.