1 files changed, 3 insertions, 2 deletions
diff --git a/os/io/platforms/STM32/spi_lld.h b/os/io/platforms/STM32/spi_lld.h
index 54dcbfff3..a6041f060 100644
--- a/os/io/platforms/STM32/spi_lld.h
+++ b/os/io/platforms/STM32/spi_lld.h
@@ -186,8 +186,9 @@ extern "C" {
   void spi_lld_select(SPIDriver *spip);
   void spi_lld_unselect(SPIDriver *spip);
   void spi_lld_ignore(SPIDriver *spip, size_t n);
-  void spi_lld_exchange(SPIDriver *spip, size_t n, void *txbuf, void *rxbuf);
-  void spi_lld_send(SPIDriver *spip, size_t n, void *txbuf);
+  void spi_lld_exchange(SPIDriver *spip, size_t n,
+                        const void *txbuf, void *rxbuf);
+  void spi_lld_send(SPIDriver *spip, size_t n, const void *txbuf);
   void spi_lld_receive(SPIDriver *spip, size_t n, void *rxbuf);
 #ifdef __cplusplus
 }