Double-SD-card real-time data recording device

The invention discloses a double-SD-card real-time data recording device and a compatible FAT32 file system, the device comprises a microprocessor, an internal SD card and an external SD card, the microprocessor is integrated with an SPI controller and an SDIO controller, the microprocessor is connected with the internal SD card through the SPI controller, the microprocessor is connected with the external SD card through the SDIO controller, and the SDIO controller communicates with the microprocessor. A double-SD-card storage mode is used, the internal SD card is installed in the data recording device, and data are recorded at any time; the external SD card can be inserted or pulled out at any time to exchange data between a computer and the device; when file data in the SD card is accessed, a pre-allocated sector address can be quickly positioned to perform read-write operation, so that the use of cluster chain access of FAT32 and an allocation mechanism of blank clusters is avoided, the read-write time is