Differences

This shows you the differences between two versions of the page.

--- cvend [2026/01/21 09:19] – v
+++ cvend [2026/01/28 00:26] (current) – Add title asb
@@ Line 1: / Line 1: @@
+====== cVEND NFC Reader ======
 cVEND is the NFC reader on the bottom half of the PM3
 {{ :cvend_plug.pdf |}}
+The associated serial device appears to be at /dev/ttymxc3 in Linux.
@@ Line 52: / Line 57: @@
 There are 4 bytes appended at the end of some messages (presumably those with ID LSB=1, if the Rust struct description is accurate?) which is not a CRC32 with any polynomial I recognize, but a CRC32 of (message + CRC) is always 0xFFFFFFFF. These 4 bytes are NOT included in the length.
+The checksum is _appended_, as can be seen by it following the log message (after the final \0).
+is it a _little endian_, _bit negated_ CRC32. Which is weird because the length is big endian?..
+* Host only sends two types of messages after initialization - both of type 0xBC. One is length 1 and the body is always 0x60 (+ negated CRC 2A714F60), the other is of length 4 and the body is always 5A2BC3F9 (+ negated-CRC 11A8A56A)