为什么ESP32-S3的SDIO接SD卡，用1bit数据和4bit数据读取文件，速度几乎没有差别

[122722629@qq.com]

4bit不是应该快很多吗，但是实际并没有快多少，600多K的文件，要700ms才能读完。

这是1bit时的日志：

Code: Untitled.cpp Select all

I (0) cpu_start: App cpu up.

I (1218) spiram: SPI SRAM memory test OK

I (1227) cpu_start: Pro cpu start user code

I (1227) cpu_start: cpu freq: 240000000

I (1227) cpu_start: Application information:

I (1230) cpu_start: Project name:     sd_card

I (1235) cpu_start: App version:      ac75c64-dirty

I (1241) cpu_start: Compile time:     Apr  6 2022 14:41:49

I (1247) cpu_start: ELF file SHA256:  9c75e896892f3e6c...

I (1253) cpu_start: ESP-IDF:          v4.4-dirty

I (1258) heap_init: Initializing. RAM available for dynamic allocation:

I (1266) heap_init: At 3FC951D8 len 0004AE28 (299 KiB): D/IRAM

I (1272) heap_init: At 3FCE0000 len 0000EE34 (59 KiB): STACK/DRAM

I (1279) heap_init: At 3FCF0000 len 00008000 (32 KiB): DRAM

I (1285) heap_init: At 600FE000 len 00002000 (8 KiB): RTCRAM

I (1292) spiram: Adding pool of 8192K of external SPI memory to heap allocator

I (1300) spi_flash: detected chip: gd

I (1304) spi_flash: flash io: dio

I (1308) sleep: Configure to isolate all GPIO pins in sleep state

I (1315) sleep: Enable automatic switching of GPIO sleep configuration

I (1322) cpu_start: Starting scheduler on PRO CPU.

I (0) cpu_start: Starting scheduler on APP CPU.

I (1337) spiram: Reserving pool of 32K of internal memory for DMA/internal allocations

I (1346) example: Initializing SD card

I (1350) example: Using SDMMC peripheral

I (1355) example: Mounting filesystem

I (1359) gpio: GPIO[8]| InputEn: 0| OutputEn: 0| OpenDrain: 0| Pullup: 1| Pulldown: 0| Intr:0 

I (1369) gpio: GPIO[10]| InputEn: 0| OutputEn: 0| OpenDrain: 0| Pullup: 1| Pulldown: 0| Intr:0 

I (1378) gpio: GPIO[6]| InputEn: 0| OutputEn: 0| OpenDrain: 0| Pullup: 1| Pulldown: 0| Intr:0 

I (1435) example: Filesystem mounted

Name: SD

Type: SDSC

Speed: 20 MHz

Size: 121MB

I (1436) example: Opening file /sdcard/hello.txt

I (1446) example: File written

I (1450) example: Renaming file /sdcard/hello.txt to /sdcard/foo.txt

I (1452) example: Reading file /sdcard/foo.txt

I (1456) example: Read from file: 'Hello SD   !'

I (1556) example: list: /,open succeed

I (1557) example: file: 2.MJP , size: 622178 , fattrib: 32

I (1557) example: file: FOO.TXT , size: 13 , fattrib: 32

I (1562) example: free_heap_size = 8082979

I (1567) example: free_heap_size = 8078883

I (2279) example: read 622178 bytes in 707 ms

I (2280) example: free_heap_size = 8082979



I (2280) example: Card unmounted

这是4bit时的日志：

Code: Untitled.cpp Select all

I (0) cpu_start: App cpu up.

I (1218) spiram: SPI SRAM memory test OK

I (1227) cpu_start: Pro cpu start user code

I (1227) cpu_start: cpu freq: 240000000

I (1227) cpu_start: Application information:

I (1230) cpu_start: Project name:     sd_card

I (1235) cpu_start: App version:      ac75c64-dirty

I (1241) cpu_start: Compile time:     Apr  6 2022 14:41:49

I (1247) cpu_start: ELF file SHA256:  ca6d01d26a856673...

I (1253) cpu_start: ESP-IDF:          v4.4-dirty

I (1258) heap_init: Initializing. RAM available for dynamic allocation:

I (1266) heap_init: At 3FC951D8 len 0004AE28 (299 KiB): D/IRAM

I (1272) heap_init: At 3FCE0000 len 0000EE34 (59 KiB): STACK/DRAM

I (1279) heap_init: At 3FCF0000 len 00008000 (32 KiB): DRAM

I (1285) heap_init: At 600FE000 len 00002000 (8 KiB): RTCRAM

I (1292) spiram: Adding pool of 8192K of external SPI memory to heap allocator

I (1300) spi_flash: detected chip: gd

I (1304) spi_flash: flash io: dio

I (1308) sleep: Configure to isolate all GPIO pins in sleep state

I (1315) sleep: Enable automatic switching of GPIO sleep configuration

I (1322) cpu_start: Starting scheduler on PRO CPU.

I (0) cpu_start: Starting scheduler on APP CPU.

I (1337) spiram: Reserving pool of 32K of internal memory for DMA/internal allocations

I (1346) example: Initializing SD card

I (1350) example: Using SDMMC peripheral

I (1355) example: Mounting filesystem

I (1359) gpio: GPIO[8]| InputEn: 0| OutputEn: 0| OpenDrain: 0| Pullup: 1| Pulldown: 0| Intr:0

I (1369) gpio: GPIO[10]| InputEn: 0| OutputEn: 0| OpenDrain: 0| Pullup: 1| Pulldown: 0| Intr:0

I (1378) gpio: GPIO[6]| InputEn: 0| OutputEn: 0| OpenDrain: 0| Pullup: 1| Pulldown: 0| Intr:0

I (1387) gpio: GPIO[7]| InputEn: 0| OutputEn: 0| OpenDrain: 0| Pullup: 1| Pulldown: 0| Intr:0

I (1396) gpio: GPIO[12]| InputEn: 0| OutputEn: 0| OpenDrain: 0| Pullup: 1| Pulldown: 0| Intr:0

I (1406) gpio: GPIO[5]| InputEn: 0| OutputEn: 1| OpenDrain: 0| Pullup: 0| Pulldown: 0| Intr:0

I (1463) example: Filesystem mounted

Name: SD

Type: SDSC

Speed: 20 MHz

Size: 121MB

I (1464) example: Opening file /sdcard/hello.txt

I (1474) example: File written

I (1530) example: Renaming file /sdcard/hello.txt to /sdcard/foo.txt

I (1532) example: Reading file /sdcard/foo.txt

I (1533) example: Read from file: 'Hello SD   !'

I (1633) example: list: /,open succeed

I (1633) example: file: 2.MJP , size: 622178 , fattrib: 32

I (1633) example: file: FOO.TXT , size: 13 , fattrib: 32

I (1639) example: free_heap_size = 8082979

I (1643) example: free_heap_size = 8078883

I (2356) example: read 622178 bytes in 707 ms

I (2356) example: free_heap_size = 8082979



I (2357) example: Card unmounted

[Yake]

你看下你的 SD 卡速率是多少，很多时候是受限于 SD 卡的速率。用 PC 读写试试速率

[Jinsc_esp32]

因为你用的是C语言提供的接口，读写用fatfs的接口就行了