crewID/libnfc
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Fix packet length checksum computation.

Browse source 
The doc says LCS (aka abtTx[4]) must be set so that the lower byte of LCS+LEN
(aka abtTx[3]) is 0x00.  This has not to be related to the USB buffer size, so
that we can adjust it without breaking down the libnfc.
This commit is contained in:
Romain Tartiere 2010-07-25 16:31:53 +00:00
parent 7f9f907bc2
commit af584bd474
1 changed files with 1 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
libnfc/drivers/pn53x_usb.c
View file

@ -251,7 +251,7 @@ bool pn53x_usb_transceive(const nfc_device_spec_t nds, const byte_t* pbtTx, cons
// Packet length = data length (len) + checksum (1) + end of stream marker (1)
abtTx[3] = szTxLen;
// Packet length checksum
abtTx[4] = BUFFER_LENGTH - abtTx[3];
abtTx[4] = 0x0100 - abtTx[3];
// Copy the PN53X command into the packet abtTx
memmove(abtTx+5,pbtTx,szTxLen);