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Always ACK on transmission.

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Summary: Make sending ACK on message transmission skipable.
Owner: rtartiere@il4p.fr
Cc: rtartiere@il4p.fr
Status: New
I guess that for performance reasons, some advance users would prefer to skip
sending the non-mandatory ACK on data transmission.  They may also perform a
quicker check of the ACK returned by the chip after sending the command and
before receiving the response (not sure about this one).

It will probably be a ./configure option disabled by default that allows some "shortcuts" to perform NFC hacking.
This commit is contained in:
Romain Tartiere
2010-08-13 16:02:18 +00:00
parent f4bc39bf41
commit 57b775bae2
3 changed files with 24 additions and 0 deletions
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4
libnfc/drivers/pn53x_usb.c
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@@ -243,6 +243,7 @@ bool pn53x_usb_transceive(nfc_device_t* pnd, const byte_t* pbtTx, const size_t s
byte_t abtTx[BUFFER_LENGTH] = { 0x00, 0x00, 0xff }; // Every packet must start with "00 00 ff"
byte_t abtRx[BUFFER_LENGTH];
usb_spec_t* pus = (usb_spec_t*)pnd->nds;
// TODO: Move this one level up for libnfc-1.6
uint8_t ack_frame[] = { 0x00, 0x00, 0xff, 0x00, 0xff, 0x00 };
// Packet length = data length (len) + checksum (1) + end of stream marker (1)
@@ -298,6 +299,9 @@ bool pn53x_usb_transceive(nfc_device_t* pnd, const byte_t* pbtTx, const size_t s
PRINT_HEX("RX", abtRx,ret);
#endif
#ifdef DEBUG
PRINT_HEX("TX", ack_frame,6);
#endif
usb_bulk_write(pus->pudh, pus->uiEndPointOut, (char *)ack_frame, 6, USB_TIMEOUT);
// When the answer should be ignored, just return a succesful result