Sifive hifive b wifi: only receive 'C'

HiFive1 Rev B
1

when I send ‘AT’ command to esp32 from spi1, getting ‘C’ response.

but send ‘AT’ to esp32, should be get ‘OK’.

environment:
freedom-sdk
ubuntu 20.04 x64

main.c:

drive_spi.h

#include “drive_spi.h”:

volatile SPI_STRUCT *spi_init(uint32_t spi_adress)
{
volatile SPI_STRUCT new_spi_device = (volatile SPI_STRUCT)spi_adress;
return new_spi_device;
}

drive_spi.c

thanks a lot.