feat(pn53x): transceive_bits (wip)

acr122usb/device.go

@@ -402,3 +402,7 @@ func (pnd *Acr122UsbDevice) SetPropertyDuration(property gonfc.Property, value t
 func (pnd *Acr122UsbDevice) InitiatorTargetIsPresent(nt *gonfc.NfcTarget) (bool, error) {
 	return pnd.chip.InitiatorTargetIsPresent(nt)
 }
+
+func (pnd *Acr122UsbDevice) InitiatorTransceiveBits(tx []byte, txBits int, txPar []byte, rx []byte, rxPar []byte) (int, error) {
+	return pnd.chip.InitiatorTransceiveBits(tx, txBits, txPar, rx, rxPar)
+}

device.go

@@ -22,7 +22,7 @@ type Device interface {
 	// InitiatorSelectDepTarget(ndm DepMode, nbr BaudRate, pndiInitiator *DepInfo, timeout time.Duration) (*NfcTarget, error)
 	InitiatorDeselectTarget() error
 	InitiatorTransceiveBytes(tx, rx []byte, timeout time.Duration) (int, error)
-	// InitiatorTransceiveBits()
+	InitiatorTransceiveBits(tx []byte, txBits int, txPar []byte, rx []byte, rxPar []byte) (int, error)
 	// InitiatorTransceiveBytesTimed()
 	// InitiatorTransceiveBitsTimed()
 	InitiatorTargetIsPresent(nt *NfcTarget) (bool, error)

periphio/i2cdevice.go

@@ -96,3 +96,7 @@ func (d *PeriphioI2CDevice) GetSupportedBaudRate(nmt gonfc.ModulationType) ([]go
 func (d *PeriphioI2CDevice) GetSupportedBaudRateTargetMode(nmt gonfc.ModulationType) ([]gonfc.BaudRate, error) {
 	panic("TODO")
 }
+
+func (pnd *PeriphioI2CDevice) InitiatorTransceiveBits(tx []byte, txBits int, txPar []byte, rx []byte, rxPar []byte) (int, error) {
+	return pnd.chip.InitiatorTransceiveBits(tx, txBits, txPar, rx, rxPar)
+}

pigpio/pn532i2c.device.go

@@ -207,3 +207,7 @@ func (pnd *PN532PiGPIOI2CDevice) GetSupportedBaudRate(mt gonfc.ModulationType) (
 func (pnd *PN532PiGPIOI2CDevice) GetSupportedBaudRateTargetMode(mt gonfc.ModulationType) ([]gonfc.BaudRate, error) {
 	return pnd.chip.GetSupportedBaudRate(gonfc.N_TARGET, mt)
 }
+
+func (pnd *PN532PiGPIOI2CDevice) InitiatorTransceiveBits(tx []byte, txBits int, txPar []byte, rx []byte, rxPar []byte) (int, error) {
+	return pnd.chip.InitiatorTransceiveBits(tx, txBits, txPar, rx, rxPar)
+}

pn53x/initiator.transceivebits.go

@@ -0,0 +1,159 @@
+package pn53x
+
+import (
+	"errors"
+
+	"github.com/maitredede/gonfc"
+)
+
+// InitiatorTransceiveBits
+// chips/pn53x.c pn53x_initiator_transceive_bits
+func (pnd *Chip) InitiatorTransceiveBits(pbtTx []byte, szTxBits int, pbtTxPar []byte, pbtRx []byte, pbtRxPar []byte) (int, error) {
+
+	var szFrameBits int
+
+	abtCmd := make([]byte, PN53x_EXTENDED_FRAME__DATA_MAX_LEN)
+	abtCmd[0] = byte(InCommunicateThru)
+
+	// Check if we should prepare the parity bits ourself
+	if (!pnd.bPar.Get()) && (szTxBits > 0) {
+		// Convert data with parity to a frame
+		frame, err := WrapFrame(pbtTx, szTxBits, pbtTxPar)
+		if err != nil {
+			return 0, err
+		}
+		for i := 0; i < min(len(frame), len(abtCmd)-1); i++ {
+			abtCmd[i+1] = frame[i]
+		}
+		szFrameBits = len(frame)
+	} else {
+		szFrameBits = szTxBits
+	}
+
+	// Retrieve the leading bits
+	ui8Bits := byte(szFrameBits) % 8
+
+	// Get the amount of frame bytes + optional (1 byte if there are leading bits)
+	var lead int
+	if ui8Bits == 0 {
+		lead = 0
+	} else {
+		lead = 1
+	}
+	szFrameBytes := (szFrameBits / 8) + lead
+
+	// When the parity is handled before us, we just copy the data
+	if pnd.bPar.Get() {
+		for i := 0; i < szFrameBytes; i++ {
+			abtCmd[i+1] = pbtTx[i]
+		}
+	}
+
+	// Set the amount of transmission bits in the PN53X chip register
+	if err := pnd.setTxBits(ui8Bits); err != nil {
+		return 0, err
+	}
+
+	// Send the frame to the PN53X chip and get the answer
+	// We have to give the amount of bytes + (the command byte 0x42)
+	abtRx := make([]byte, PN53x_EXTENDED_FRAME__DATA_MAX_LEN)
+	szRx, err := pnd.transceive(abtCmd[:szFrameBytes+1], abtRx, -1)
+	if err != nil {
+		return 0, err
+	}
+	// Get the last bit-count that is stored in the received byte
+	ui8rcc, err := pnd.readRegister(PN53X_REG_CIU_Control)
+	if err != nil {
+		return 0, err
+	}
+	ui8Bits = ui8rcc & SYMBOL_RX_LAST_BITS
+
+	// Recover the real frame length in bits
+	var tern int
+	if ui8Bits == 0 {
+		tern = 0
+	} else {
+		tern = 1
+	}
+	szFrameBits = ((szRx - 1 - tern) * 8) + int(ui8Bits)
+
+	var szRxBits int
+	if len(pbtRx) > 0 {
+		// Ignore the status byte from the PN53X here, it was checked earlier in pn53x_transceive()
+		// Check if we should recover the parity bits ourself
+		if !pnd.bPar.Get() {
+			// Unwrap the response frame
+			frame, framePar, err := UnwrapFrame(abtRx[1:], szFrameBits)
+			if err != nil {
+				return 0, err
+			}
+			szRxBits = len(frame)
+			for i := 0; i < szRxBits; i++ {
+				pbtRx[i] = frame[i]
+				pbtRxPar[i] = framePar[i]
+			}
+			// if ((res = pn53x_unwrap_frame(abtRx + 1, szFrameBits, pbtRx, pbtRxPar)) < 0)
+			//   return res;
+		} else {
+			// Save the received bits
+			szRxBits = szFrameBits
+			// Copy the received bytes
+			for i := 0; i < szRx-1; i++ {
+				pbtRx[i] = abtRx[i+1]
+			}
+		}
+	}
+	// Everything went successful
+	return szRxBits, nil
+}
+
+// WrapFrame
+// chips/pn53x.c pn53x_wrap_frame
+func WrapFrame(pbtTx []byte, szTxBits int, pbtTxPar []byte) ([]byte, error) {
+	szBitsLeft := szTxBits
+
+	// Make sure we should frame at least something
+	if szBitsLeft == 0 {
+		return nil, gonfc.NFC_ECHIP
+	}
+
+	panic(errors.New("TODO : pn53x.WrapFrame"))
+	// var szFrameBits int
+	// // Handle a short response (1byte) as a special case
+	// if szBitsLeft < 9 {
+	// 	frame := pbtTx[:szTxBits]
+	// 	return frame, nil
+	// }
+
+	// // We start by calculating the frame length in bits
+	// szFrameBits = szTxBits + (szTxBits / 8)
+
+	// // Parse the data bytes and add the parity bits
+	// // This is really a sensitive process, mirror the frame bytes and append parity bits
+	// // buffer = mirror(frame-byte) + parity + mirror(frame-byte) + parity + ...
+	// // split "buffer" up in segments of 8 bits again and mirror them
+	// // air-bytes = mirror(buffer-byte) + mirror(buffer-byte) + mirror(buffer-byte) + ..
+	// for {
+	// 	// Reset the temporary frame byte;
+	// 	var btFrame byte = 0
+	// 	for uiBitPos := byte(0); uiBitPos < 8; uiBitPos++ {
+
+	// 	}
+	// 	// Every 8 data bytes we lose one frame byte to the parities
+	// 	pbtFrame++
+	// }
+}
+
+// WrapFrame
+// chips/pn53x.c pn53x_unwrap_frame
+func UnwrapFrame(pbtFrame []byte, szFrameBits int) ([]byte, []byte, error) {
+	var pbtRx []byte
+	var pbtRxPar []byte
+	szBitsLeft := szFrameBits
+	// Make sure we should frame at least something
+	if szBitsLeft == 0 {
+		return pbtRx, pbtRxPar, gonfc.NFC_ECHIP
+	}
+
+	panic(errors.New("TODO : pn53x.UnwrapFrame"))
+}