send LF commands to TAG (locomread)

armsrc/appmain.c

@@ -91,12 +91,6 @@ void DbpIntegers(int x1, int x2, int x3)
 
 void AcquireRawAdcSamples125k(BOOL at134khz)
 {
-	BYTE *dest = (BYTE *)BigBuf;
-	int n = sizeof(BigBuf);
-	int i;
-
-	memset(dest,0,n);
-
 	if(at134khz) {
 		FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
 		FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER | FPGA_LF_READER_USE_134_KHZ);
@@ -114,6 +108,18 @@ void AcquireRawAdcSamples125k(BOOL at134khz)
 	// Now set up the SSC to get the ADC samples that are now streaming at us.
 	FpgaSetupSsc();
 
+	// Now call the acquisition routine
+	DoAcquisition125k(at134khz);
+}
+
+// split into two routines so we can avoid timing issues after sending commands //
+void DoAcquisition125k(BOOL at134khz)
+{
+	BYTE *dest = (BYTE *)BigBuf;
+	int n = sizeof(BigBuf);
+	int i;
+
+	memset(dest,0,n);
 	i = 0;
 	for(;;) {
 		if(SSC_STATUS & (SSC_STATUS_TX_READY)) {
@@ -132,6 +138,64 @@ void AcquireRawAdcSamples125k(BOOL at134khz)
 	DbpIntegers(dest[0], dest[1], at134khz);
 }
 
+void ModThenAcquireRawAdcSamples125k(int delay_off,int period_0,int period_1,BYTE *command)
+{
+	BOOL at134khz;
+
+	// see if 'h' was specified
+	if(command[strlen(command) - 1] == 'h')
+		at134khz= TRUE;
+	else
+		at134khz= FALSE;
+	
+	if(at134khz) {
+		FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
+		FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER | FPGA_LF_READER_USE_134_KHZ);
+	} else {
+		FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
+		FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER | FPGA_LF_READER_USE_125_KHZ);
+	}
+
+	// Give it a bit of time for the resonant antenna to settle.
+	SpinDelay(50);
+
+	// Now set up the SSC to get the ADC samples that are now streaming at us.
+	FpgaSetupSsc();
+
+	// now modulate the reader field
+	while(*command != '\0' && *command != ' ')
+		{
+		FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+		LED_D_OFF();
+		SpinDelayUs(delay_off);
+		if(at134khz) {
+			FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
+			FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER | FPGA_LF_READER_USE_134_KHZ);
+		} else {
+			FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
+			FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER | FPGA_LF_READER_USE_125_KHZ);
+		}
+		LED_D_ON();
+		if(*(command++) == '0')
+			SpinDelayUs(period_0);
+		else
+			SpinDelayUs(period_1);
+		}
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+	LED_D_OFF();
+	SpinDelayUs(delay_off);
+	if(at134khz) {
+		FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
+		FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER | FPGA_LF_READER_USE_134_KHZ);
+	} else {
+		FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
+		FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER | FPGA_LF_READER_USE_125_KHZ);
+	}
+
+	// now do the read
+	DoAcquisition125k(at134khz);
+}
+
 //-----------------------------------------------------------------------------
 // Read an ADC channel and block till it completes, then return the result
 // in ADC units (0 to 1023). Also a routine to average 32 samples and
@@ -607,6 +671,10 @@ void UsbPacketReceived(BYTE *packet, int len)
 			AcquireRawAdcSamples125k(c->ext1);
 			break;
 
+		case CMD_MOD_THEN_ACQUIRE_RAW_ADC_SAMPLES_125K:
+			ModThenAcquireRawAdcSamples125k(c->ext1,c->ext2,c->ext3,c->d.asBytes);
+			break;
+
 		case CMD_ACQUIRE_RAW_ADC_SAMPLES_ISO_15693:
 			AcquireRawAdcSamplesIso15693();
 			break;
@@ -793,6 +861,28 @@ void AppMain(void)
 	}
 }
 
+void SpinDelayUs(int us)
+{
+	int ticks = (48*us) >> 10;
+
+	// Borrow a PWM unit for my real-time clock
+	PWM_ENABLE = PWM_CHANNEL(0);
+	// 48 MHz / 1024 gives 46.875 kHz
+	PWM_CH_MODE(0) = PWM_CH_MODE_PRESCALER(10);
+	PWM_CH_DUTY_CYCLE(0) = 0;
+	PWM_CH_PERIOD(0) = 0xffff;
+
+	WORD start = (WORD)PWM_CH_COUNTER(0);
+
+	for(;;) {
+		WORD now = (WORD)PWM_CH_COUNTER(0);
+		if(now == (WORD)(start + ticks)) {
+			return;
+		}
+		WDT_HIT();
+	}
+}
+
 void SpinDelay(int ms)
 {
 	int ticks = (48000*ms) >> 10;

armsrc/apps.h

@@ -12,8 +12,11 @@ void AppMain(void);
 void DbpIntegers(int a, int b, int c);
 void DbpString(char *str);
 void SpinDelay(int ms);
+void SpinDelayUs(int us);
 void ToSendStuffBit(int b);
 void ToSendReset(void);
+void AcquireRawAdcSamples125k(BOOL at134khz);
+void DoAcquisition125k(BOOL at134khz);
 extern int ToSendMax;
 extern BYTE ToSend[];
 extern DWORD BigBuf[];

include/usb_cmd.h

@@ -48,6 +48,7 @@ typedef struct {
 #define CMD_HID_SIM_TAG								0x0209	// ## New command: simulate HID tag by ID
 #define CMD_SET_LF_DIVISOR							0x020A
 #define CMD_SWEEP_LF								0x020B
+#define CMD_MOD_THEN_ACQUIRE_RAW_ADC_SAMPLES_125K			0x020C
 
 // For the 13.56 MHz tags
 #define CMD_ACQUIRE_RAW_ADC_SAMPLES_ISO_15693		0x0300

winsrc/command.cpp

@@ -9,6 +9,7 @@
 #include <stdio.h>
 #include <limits.h>
 #include <math.h>
+#include <unistd.h>
 
 #include "prox.h"
 #include "../common/iso14443_crc.c"
@@ -535,6 +536,21 @@ static void CmdLoread(char *str)
 	SendCommand(&c, FALSE);
 }
 
+/* send a command before reading */
+static void CmdLoCommandRead(char *str)
+{
+	static char dummy[3];
+
+	dummy[0]= ' ';
+	
+	UsbCommand c;
+	c.cmd = CMD_MOD_THEN_ACQUIRE_RAW_ADC_SAMPLES_125K;
+	sscanf(str, "%i %i %i %s %s", &c.ext1, &c.ext2, &c.ext3, &c.d.asBytes,&dummy+1);
+	// in case they specified 'h'
+	strcpy(&c.d.asBytes + strlen(c.d.asBytes),dummy);
+	SendCommand(&c, FALSE);
+}
+
 static void CmdLosamples(char *str)
 {
 	int cnt = 0;
@@ -2065,7 +2081,7 @@ static void Cmdmanchestermod(char *str)
  *               Typical values can be 64, 32, 128...
  */
 static void Cmdmanchesterdemod(char *str) {
-	int i, j, invert= 0;
+	int i, j;
 	int bit;
 	int clock;
 	int lastval;
@@ -2077,16 +2093,6 @@ static void Cmdmanchesterdemod(char *str) {
 	int bit2idx = 0;
 	int warnings = 0;
 
-	/* check if we're inverting output */
- 	if(*str == 'i')
-	{
-		PrintToScrollback("Inverting output");
-		invert= 1;
-		do
-			++str;
-		while(*str == ' '); // in case a 2nd argument was given
-	}
-
 	/* Holds the decoded bitstream: each clock period contains 2 bits       */
 	/* later simplified to 1 bit after manchester decoding.                 */
 	/* Add 10 bits to allow for noisy / uncertain traces without aborting   */
@@ -2157,7 +2163,7 @@ static void Cmdmanchesterdemod(char *str) {
 			if (!hithigh || !hitlow)
 				bit ^= 1;
 
-			BitStream[bit2idx++] = bit ^ invert;
+			BitStream[bit2idx++] = bit;
 		}
 	}
 
@@ -2209,9 +2215,9 @@ static void Cmdmanchesterdemod(char *str) {
 	// to stop output at the final bitidx2 value, not bitidx
 	for (i = 0; i < bitidx; i += 2) {
 		if ((BitStream[i] == 0) && (BitStream[i+1] == 1)) {
-				BitStream[bit2idx++] = 1 ^ invert;
+			BitStream[bit2idx++] = 1;
 		} else if ((BitStream[i] == 1) && (BitStream[i+1] == 0)) {
-			BitStream[bit2idx++] = 0 ^ invert;
+			BitStream[bit2idx++] = 0;
 		} else {
 			// We cannot end up in this state, this means we are unsynchronized,
 			// move up 1 bit:
@@ -2450,11 +2456,12 @@ static struct {
 	"lcd",				CmdLcd,0,			"<HEX command> <count> -- Send command/data to LCD",
 	"lcdreset",			CmdLcdReset,0,		"    Hardware reset LCD",
 	"load",				CmdLoad,1,		"<filename> -- Load trace (to graph window",
+	"locomread",			CmdLoCommandRead,0,		"<off period> <'0' period> <'1' period> <command> ['h'] -- Modulate LF reader field to send command before read (all periods in microseconds) (option 'h' for 134)",
 	"loread",			CmdLoread,0,		"['h'] -- Read 125/134 kHz LF ID-only tag (option 'h' for 134)",
 	"losamples",		CmdLosamples,0,		"[128 - 16000] -- Get raw samples for LF tag",
 	"losim",			CmdLosim,0,		"    Simulate LF tag",
 	"ltrim",			CmdLtrim,1,		"<samples> -- Trim samples from left of trace",
-	"mandemod",			Cmdmanchesterdemod,1,	"[i] [clock rate] -- Manchester demodulate binary stream (option 'i' to invert output)",
+	"mandemod",			Cmdmanchesterdemod,1,	"[clock rate] -- Try a Manchester demodulation on a binary stream",
 	"manmod",			Cmdmanchestermod,1,	"[clock rate] -- Manchester modulate a binary stream",
 	"norm",				CmdNorm,1,		"    Normalize max/min to +/-500",
 	"plot",				CmdPlot,1,		"    Show graph window",

winsrc/prox.h

@@ -51,6 +51,7 @@ int CmdClearGraph(int redraw);
 static void CmdAppendGraph(int redraw, int clock, int bit);
 static void CmdEM410xsim(char *str);
 static void CmdLosim(char *str);
+static void CmdLoCommandRead(char *str);
 static void CmdLoread(char *str);
 static void CmdLosamples(char *str);
 static void CmdBitsamples(char *str);