Wokwi crashes on Swift code, probably simulating a TFT display

[libewa]

Describe the bug
When running my project, Wokwi consistently crashes setting the D/C pin.

To Reproduce

• Download my project: https://github.com/libewa/swiftflag
• Install and use a nightly Swift toolchain
• Build for ESP32-C3
• Run the project with Wokwi CLI

Expected behavior
Wokwi should simulate the ESP32 and TFT waving a flag.

Environment (please complete the following information):

• OS: macOS Sequoia 15.5
• Browser n/a
• Version 0.16.2

Additional Context

stdout

Wokwi CLI v0.16.2 (ce38a7079ab7)
Detected IDF project in .
Connected to Wokwi Simulation API 1.0.0-20250706-gdd259c8a
Starting simulation...
ESP-ROM:esp32c3-api1-20210207
Build:Feb  7 2021
rst:0x1 (POWERON),boot:0xc (SPI_FAST_FLASH_BOOT)
SPIWP:0xee
mode:DIO, clock div:1
load:0x3fcd5820,len:0x1574
load:0x403cc710,len:0xc30
load:0x403ce710,len:0x2f58
entry 0x403cc71a
I (2) boot: ESP-IDF v5.4-dirty 2nd stage bootloader
I (2) boot: compile time Jul  6 2025 17:29:50
I (2) boot: chip revision: v0.3
I (2) boot: efuse block revision: v1.0
I (3) boot.esp32c3: SPI Speed      : 80MHz
I (3) boot.esp32c3: SPI Mode       : DIO
I (4) boot.esp32c3: SPI Flash Size : 4MB
I (4) boot: Enabling RNG early entropy source...
I (5) boot: Partition Table:
I (5) boot: ## Label            Usage          Type ST Offset   Length
I (6) boot:  0 nvs              WiFi data        01 02 00009000 00006000
I (6) boot:  1 phy_init         RF data          01 01 0000f000 00001000
I (7) boot:  2 factory          factory app      00 00 00010000 00100000
I (8) boot: End of partition table
I (8) esp_image: segment 0: paddr=00010020 vaddr=3c030020 size=107dch ( 67548) map
I (12) esp_image: segment 1: paddr=00020804 vaddr=3fc8da00 size=0188ch (  6284) load
I (13) esp_image: segment 2: paddr=00022098 vaddr=40380000 size=0d930h ( 55600) load
I (16) esp_image: segment 3: paddr=0002f9d0 vaddr=50000200 size=0001ch (    28) load
I (16) esp_image: segment 4: paddr=0002f9f4 vaddr=00000000 size=00624h (  1572) 
I (16) esp_image: segment 5: paddr=00030020 vaddr=42000020 size=2c078h (180344) map
I (26) boot: Loaded app from partition at offset 0x10000
I (26) boot: Disabling RNG early entropy source...
I (27) cpu_start: Unicore app
I (14) cpu_start: Pro cpu start user code
I (14) cpu_start: cpu freq: 160000000 Hz
I (14) app_init: Application information:
I (14) app_init: Project name:     swiftflag
I (14) app_init: App version:      d4c67a9-dirty
I (15) app_init: Compile time:     Jul  6 2025 17:36:30
I (15) app_init: ELF file SHA256:  c11aca3b1...
I (15) app_init: ESP-IDF:          v5.4-dirty
I (15) efuse_init: Min chip rev:     v0.3
I (16) efuse_init: Max chip rev:     v1.99 
I (16) efuse_init: Chip rev:         v0.3
I (16) heap_init: Initializing. RAM available for dynamic allocation:
I (16) heap_init: At 3FC90D40 len 0002F2C0 (188 KiB): RAM
I (17) heap_init: At 3FCC0000 len 0001C710 (113 KiB): Retention RAM
I (17) heap_init: At 3FCDC710 len 00002950 (10 KiB): Retention RAM
I (18) heap_init: At 5000021C len 00001DCC (7 KiB): RTCRAM
I (18) spi_flash: detected chip: gd
I (18) spi_flash: flash io: dio
I (18) sleep_gpio: Configure to isolate all GPIO pins in sleep state
I (19) sleep_gpio: Enable automatic switching of GPIO sleep configuration
I (19) main_task: Started on CPU0
I (21) main_task: Calling app_main()
I (23) gpio: GPIO[3]| InputEn: 1| OutputEn: 1| OpenDrain: 0| Pullup: 0| Pulldown: 0| Intr:0 
I (32) gpio: GPIO[2]| InputEn: 1| OutputEn: 1| OpenDrain: 0| Pullup: 0| Pulldown: 0| Intr:0 
I (40) gpio: GPIO[4]| InputEn: 1| OutputEn: 1| OpenDrain: 0| Pullup: 0| Pulldown: 0| Intr:0 
I (49) gpio: GPIO[10]| InputEn: 1| OutputEn: 1| OpenDrain: 0| Pullup: 0| Pulldown: 0| Intr:0 
I (56) gpio: GPIO[8]| InputEn: 1| OutputEn: 0| Open

Error message

API Error: Connection to wss://wokwi.com/api/ws/beta closed unexpectedly: code 1006

[urish]

Thanks for reporting!

Does the same code work on a physical device?
And does it work in Wokwi for VS Code?

Can you please attach a pre compiled binary + elf file?

[libewa]

I don't actually have a physical ESP32-C3. I'd like to, as this is for a school project. (panic laughter)

Wokwi VS Code has the same issue and crashes at the same time, but Wokwi CLI gave me the errors too.

ELF and BIN are not allowed as attachments on GitHub, how can I send them?

[urish]

You can zip them and then attach

[libewa]

Here you go:
Archiv.zip

[urish]

Thanks, the issue reproduces. Looks like the code uses GPIO11, which is not available on the esp32-c3-devkitm-1 board, and that causes the simulation to hang. Working on a fix.

[urish]

Pushed a fix, now the simulator does not hang anymore when trying to use GPIO11 on the ESP32-C3 DevKit M-1

However, with your code, there's still nothing on the screen. It looks the the SPI in your code is not configured to use the correct pin numbers, and thus, the data does not go to the display: