Refer to PN532 User Manual 6.2.3:
"In the case the host controller does not detect an ACK frame within
these 15 ms, the host controller should resend the same command frame."
so here retry SAM command, it will fix the 'Unable to read ACK' issus.
The problem occurs in the following succession of events:
* Emit commands returning an answer larger than 16 bytes
* Re-enumerate USB devices without power cycle, e.g. a warm reboot of the PC
The bug can be reproduced for testing purposes with usbreset.c from
https://askubuntu.com/questions/645/how-do-you-reset-a-usb-device-from-the-command-line#661
$ lsusb|grep NFC
Bus 001 Device 010: ID 04e6:5591 SCM Microsystems, Inc. SCL3711-NFC&RW
$ sudo ./usbreset /dev/bus/usb/001/010
Resetting USB device /dev/bus/usb/001/010
Reset successful
$ echo -e "4a 01 00\n423000" |pn53x-tamashell
$ sudo ./usbreset /dev/bus/usb/001/010
Resetting USB device /dev/bus/usb/001/010
Error in ioctl: No such device
$ lsusb|grep NFC
... device disappeared
In the example above, reading 4 pages of a MFUL corrupted one single byte.
The entire buffer can be corrupted e.g. with fast-reading a MFUL EV1:
$ echo -e "4a 01 00\n423a0013"|pn53x-tamashell
The problem occurs in the following succession of events:
* Emit commands larger than 17 bytes
* Re-enumerate USB devices without power cycle, e.g. a warm reboot of the PC
The bug can be reproduced for testing purposes with usbreset.c from
https://askubuntu.com/questions/645/how-do-you-reset-a-usb-device-from-the-command-line#661
$ lsusb|grep NFC
Bus 001 Device 010: ID 04e6:5591 SCM Microsystems, Inc. SCL3711-NFC&RW
$ sudo ./usbreset /dev/bus/usb/001/010
Resetting USB device /dev/bus/usb/001/010
Reset successful
$ echo 06000000000000000000000000000000000000 |pn53x-tamashell
$ sudo ./usbreset /dev/bus/usb/001/010
Resetting USB device /dev/bus/usb/001/010
Error in ioctl: No such device
$ lsusb|grep NFC
... device disappeared
After a DESfire operation SCL3711 will sometimes enter a state where
libusb-0.x is unable to fill config field in struct usb_device. The
USB device has to be power-cycled to restore a sane state.
This introduce a work around, by using hardcoded values for endpoints
and packet size when they are unavailable.
* adam/master:
allow partial writes. tidy up usage.
vary expected dump size based on tag type
read extra mf-ul EV1 blocks
show EV1 auth PACK (tag/reader trust secret)
show EV1 storage size
add EV1 password auth to nfc-mfultralight
nfc.c:1244:19: warning: Dereference of undefined pointer value
for (int i = 0; nmt[i]; i++) {
^~~~~~
nfc.c:1256:23: warning: Dereference of undefined pointer value
for (int j = 0; nbr[j]; j++) {
^~~~~~
pn53x.c:1746:15: warning: Function call argument is an uninitialized value
*cycles = __pn53x_get_timer(pnd, pbtTxRaw[szTx + 1]);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
