Increasing the answer/command buffer size

[salmg]

Noticed that the buffer used for PN532 communication is limited by 64 bytes:

#define PN532_PACKBUFFSIZ 64

• The C-APDU command length can be up to 261 bytes (CLA-INS-P1-P2-P3-255 data bytes-Le)
• The R-APDU returned to the host controller can have a length of 258 bytes (256 data bytes-SW1-SW2)

By design, the library uses just one buffer for commands and answers with fixed size(PN532_PACKBUFFSIZ) but a very low one.

Using only 64 bytes from the PN532 buffer is almost four times less its limit. This limitation affects directly the ISO/14443A or raw communication projects.

Making some tests, I noticed that the actual library design could be implemented with a buffer size of 255 without changing anything else:

#define PN532_PACKBUFFSIZ 255

[asdfjkl]

can you confirm/deny that sending a large apdu (say 80 bytes) is possible? In my setup ( https://github.com/adafruit/Adafruit-PN532/issues/73 ) increasing the command buffer for receiving apdus works fine (large apdu replies are received ok), but sending large apdus fails.

[salmg]

I have to mentioned that I tested that buffer size using only the SPI configuration.

[caternuson]

Looks similar to #38

[mhaberler]

can you confirm/deny that sending a large apdu (say 80 bytes) is possible? In my setup ( #73 ) increasing the command buffer for receiving apdus works fine (large apdu replies are received ok), but sending large apdus fails.

see the manual reference in https://github.com/adafruit/Adafruit-PN532/issues/124 which is unambiguous