firmware: Minimal frame encodingHEADmain

This only covers the correct frame size, setting the buffer to 0 and
copy the payload over.

Missing is:

- copy destination address
- copy source address
- set frame type
- calculate and add CRC32 checksum

1 files changed, 3 insertions, 0 deletions

diff --git a/firmware/src/data_link.h b/firmware/src/data_link.h
index d2a25a1..45f58dc 100644
--- a/firmware/src/data_link.h
+++ b/firmware/src/data_link.h
@@ -9,6 +9,9 @@
 #define DL_SLIP_ESC_END 0xDC
 #define DL_SLIP_ESC_ESC 0xDD
 
+#define DL_MAX_FRAME_SIZE 1500
+
+ssize_t dl_encode_frame(uint8_t *payload, size_t len, uint8_t *dst);
 void dl_send_frame(const struct device *const uart_dev, uint8_t *buffer,
                    size_t len);