ao_spi_recv(void *block, uint16_t len, uint8_t spi_index);
void
-ao_spi_duplex(void *out, void *in, uint16_t len, uint8_t spi_index);
+ao_spi_duplex(const void *out, void *in, uint16_t len, uint8_t spi_index);
extern uint16_t ao_spi_speed[STM_NUM_SPI];