ESP32S3 (WROOM) I2S question

[PCRiscV]

Hello,

I am new to the ESP32 family but not new to embedded software programming. I am trying to get the I2S bus to work with MEMS microphone.

I have configured the I2S as follow:

Code: [Select all] [Expand/Collapse]

1.    
2. i2s_std_config_t std_cfg = {
3.         .clk_cfg = I2S_STD_CLK_DEFAULT_CONFIG(48000),
4.         .slot_cfg = I2S_STD_MSB_SLOT_DEFAULT_CONFIG(I2S_DATA_BIT_WIDTH_32BIT, I2S_SLOT_MODE_STEREO),
5.         .gpio_cfg = {
6.             .mclk = PIN_I2S_MCLK,
7.             .bclk = PIN_I2S_BCLK,
8.             .ws = PIN_I2S_WS,
9.             .dout = I2S_GPIO_UNUSED,
10.             .din = PIN_I2S_DIN,
11.             .invert_flags = {
12.                 .mclk_inv = false,
13.                 .bclk_inv = false,
14.                 .ws_inv = false,
15.             },
16.         },
17.     };

GeSHi © Codebox Plus Extension

During boot, I see the following messages:

I (300) mems: Starting the I2S bus
D (301) i2s_common: rx channel is registered on I2S0 successfully
D (301) i2s_common: MCLK is pinned to GPIO0 on I2S4
D (302) i2s_common: DMA malloc info: dma_desc_num = 6, dma_desc_buf_size = dma_frame_num * slot_num * data_bit_width = 1920
D (303) i2s_std: Clock division info: [sclk] 160000000 Hz [mdiv] 13 [mclk] 12288000 Hz [bdiv] 4 [bclk] 3072000 Hz
D (305) i2s_std: The rx channel on I2S0 has been initialized to STD mode successfully
D (306) i2s_common: i2s rx channel enabled

But when I look at the signal with the logic analyzer, I am seeing some bizarre things (see attachment #2). The WS signal is not good when low but is right when high.

Even the BCLK signal is not quite right. When the WS signal transition to high, the BCLK signal has a glitch (attachment #1)

Where should I look next?
Thanks.

[ESP_Sprite]

That honestly looks like measurement errors. Is your LA ground connected properly and is the threshold set appropriately? Long unshielded wires running in parallel can also lead to results like this.

[PCRiscV]

You are right! My mistake. I fixed my wiring and everything looks good on the logic analyzer.
Sorry about that.

[ESP_Sprite]

No worries, things like that are kinda hard to recognize when they happen on a LA. Glad to hear you're getting more sane measurements now!