NFC library using PN532 to read/write NDEF Messages to NFC tags
Dependents: Seeed_NFC_Shield_write Nucleo_test_nfc
Fork of PN532 by
Diff: PN532_SPI.cpp
- Revision:
- 0:9c6b9280c0e1
- Child:
- 1:b8cab5222fd0
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/PN532_SPI.cpp Tue Oct 08 08:33:22 2013 +0000 @@ -0,0 +1,203 @@ + +#include "PN532_SPI.h" +#include "debug.h" + +#define STATUS_READ 2 +#define DATA_WRITE 1 +#define DATA_READ 3 + +PN532_SPI::PN532_SPI(SPI &spi, PinName ss) : _ss(ss) +{ + command = 0; + _spi = &spi; + _spi->format(8, 0); + _spi->frequency(2000000); + + _ss = 1; +} + +PN532_SPI::PN532_SPI(SPI *spi, PinName ss) : _ss(ss) +{ + command = 0; + _spi = spi; + _spi->format(8, 0); + _spi->frequency(2000000); + + _ss = 1; +} + +void PN532_SPI::begin() +{ + +} + +void PN532_SPI::wakeup() +{ + _ss = 0; + wait_ms(2); + _ss = 1; +} + +int8_t PN532_SPI::writeCommand(const uint8_t buf[], uint8_t len) +{ + command = buf[0]; + writeFrame(buf, len); + + uint8_t timeout = PN532_ACK_WAIT_TIME; + while (!isReady()) { + wait_ms(1); + timeout--; + if (0 == timeout) { + DMSG("Time out when waiting for ACK\n"); + return -2; + } + } + if (readAckFrame()) { + DMSG("Invalid ACK\n"); + return PN532_INVALID_ACK; + } + return 0; +} + +int16_t PN532_SPI::readResponse(uint8_t buf[], uint8_t len, uint16_t timeout) +{ + uint16_t time = 0; + while (!isReady()) { + wait_ms(1); + time++; + if (timeout > 0 && time > timeout) { + return PN532_TIMEOUT; + } + } + + _ss = 0; + wait_ms(1); + + int16_t result; + do { + write(DATA_READ); + + if (0x00 != read() || // PREAMBLE + 0x00 != read() || // STARTCODE1 + 0xFF != read() // STARTCODE2 + ) { + + result = PN532_INVALID_FRAME; + break; + } + + uint8_t length = read(); + if (0 != (uint8_t)(length + read())) { // checksum of length + result = PN532_INVALID_FRAME; + break; + } + + uint8_t cmd = command + 1; // response command + if (PN532_PN532TOHOST != read() || (cmd) != read()) { + result = PN532_INVALID_FRAME; + break; + } + + DMSG("read: "); + DMSG_HEX(cmd); + + length -= 2; + if (length > len) { + for (uint8_t i = 0; i < length; i++) { + DMSG_HEX(read()); // dump message + } + DMSG("\nNot enough space\n"); + read(); + read(); + result = PN532_NO_SPACE; // not enough space + break; + } + + uint8_t sum = PN532_PN532TOHOST + cmd; + for (uint8_t i = 0; i < length; i++) { + buf[i] = read(); + sum += buf[i]; + + DMSG_HEX(buf[i]); + } + DMSG("\n"); + + uint8_t checksum = read(); + if (0 != (uint8_t)(sum + checksum)) { + DMSG("checksum is not ok\n"); + result = PN532_INVALID_FRAME; + break; + } + read(); // POSTAMBLE + + result = length; + } while (0); + + _ss = 1; + + return result; +} + +bool PN532_SPI::isReady() +{ + _ss = 0; + + write(STATUS_READ); + uint8_t status = read() & 1; + _ss = 1; + return status; +} + +void PN532_SPI::writeFrame(const uint8_t buf[], uint8_t len) +{ + _ss = 0; + wait_ms(2); // wake up PN532 + + write(DATA_WRITE); + write(PN532_PREAMBLE); + write(PN532_STARTCODE1); + write(PN532_STARTCODE2); + + uint8_t length = len + 1; // length of data field: TFI + DATA + write(length); + write(~length + 1); // checksum of length + + write(PN532_HOSTTOPN532); + uint8_t sum = PN532_HOSTTOPN532; // sum of TFI + DATA + + DMSG("write: "); + + for (uint8_t i = 0; i < len; i++) { + write(buf[i]); + sum += buf[i]; + + DMSG_HEX(buf[i]); + } + + uint8_t checksum = ~sum + 1; // checksum of TFI + DATA + write(checksum); + write(PN532_POSTAMBLE); + + _ss = 1; + + DMSG("\n"); +} + +int8_t PN532_SPI::readAckFrame() +{ + const uint8_t PN532_ACK[] = {0, 0, 0xFF, 0, 0xFF, 0}; + + uint8_t ackBuf[sizeof(PN532_ACK)]; + + _ss = 0; + wait_ms(1); + write(DATA_READ); + + for (uint8_t i = 0; i < sizeof(PN532_ACK); i++) { + ackBuf[i] = read(); + } + + _ss = 1; + + return memcmp(ackBuf, PN532_ACK, sizeof(PN532_ACK)); +}