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Part Number: TRF7960EVM
I am using the EVM7960A. When trying to read two IEC15693 tags with three identical least significant nibbles
the anticollision fails that the tags are not read. For example UIDs:
E00401504C3948F0
E00401504A2608F0
This event is unusual but it does occur. Any help would be appreciated.
Will
Hello Will,
I believe this is related to a bug in the firmware anticollision process, please try see this post which has an updated iso15693.c file: https://e2e.ti.com/support/wireless_connectivity/nfc_rfid/f/667/p/557855/2040789#2040789
If you use that along with the firmware provided on the TRF7960AEVM page and re-flash the TRF7960AEVM, you should be able to read the tags.
Hello Will,
Sorry for the delay in getting back to you on this - I tested the code further was able to recreate the failures. They didn't happen always for me, just sporadically, but I uncovered the root source and made one more key change (a delay is needed when getting a collision error).
Please try this updated iso15693.c file:
/****************************************************************
* FILENAME: iso15693.c
*
* BRIEF: Contain functions to search ISO15693 standardized tags
* in stand alone mode and execute ISO15693 Anticollision in
* remote mode.
*
* Copyright (C) 2010 Texas Instruments, Inc.
*
* AUTHOR(S): Reiser Peter DATE: 02 DEC 2010
*
* EDITED BY:
* *
*
****************************************************************/
#include "iso15693.h"
//===============================================================
u08_t afi = 0;
u08_t flags = 0; // stores the mask value (used in anticollision)
extern u08_t buf[300];
extern u08_t i_reg;
extern u08_t irq_flag;
extern s08_t rxtx_state;
extern u08_t rx_error_flag;
extern u08_t stand_alone_flag;
extern u08_t host_control_flag;
//===============================================================
// NAME: void Iso15693FindTag(void)
//
// BRIEF: Is used to detect ISO15693 conform tags in stand alone
// mode.
//
// INPUTS:
//
// OUTPUTS:
//
// PROCESS: [1] turn on RF driver
// [2] do a complete anticollision sequence
// [3] turn off RF driver
//
// NOTE: If ISO15693 conform Tag is detected, ISO15693 LED will
// be turned on.
//
// CHANGE:
// DATE WHO DETAIL
// 23Nov2010 RP Original Code
//===============================================================
void
Iso15693FindTag(void)
{
Trf796xTurnRfOn();
Trf796xWriteIsoControl(0x02);
// The VCD should wait at least 1 ms after it activated the
// powering field before sending the first request, to
// ensure that the VICCs are ready to receive it. (ISO15693-3)
McuDelayMillisecond(1);
flags = SIXTEEN_SLOTS;
buf[20] = 0x00;
Iso15693Anticollision(&buf[20], 0); // send Inventory request
Trf796xTurnRfOff();
Trf796xResetIrqStatus();
// clear any IRQs
}
//===============================================================
// NAME: void Iso15693Anticollision(u08_t *mask, u08_t length)
//
// BRIEF: Is used to perform a inventory cycle of 1 or 16
// timeslots.
//
// INPUTS:
// Parameters:
// u08_t *mask mask value
// u08_t length number of significant bits of
// mask value
//
// OUTPUTS:
//
// PROCESS: [1] send command
// [2] receive respond
// [3] send respond to host
//
// CHANGE:
// DATE WHO DETAIL
// 23Nov2010 RP Original Code
// 3May2011 AF Bugfix
//===============================================================
void
Iso15693Anticollision(u08_t *mask, u08_t length) // host command 0x14
{
u08_t i = 1, j = 1, command[2], no_slots, found = 0;
u08_t *p_slot_no, slot_no[17];
u08_t new_mask[8], new_length, mask_size;
u32_t size;
u08_t fifo_length = 0;
u16_t k;
slot_no[0] = 0x00;
// BUGFIX
TRF796xCheckRXWaitTime();
if((flags & BIT5) == 0x00) // flag bit5 is the number of slots indicator
{
no_slots = 16; // 16 slots if bit is cleared
Trf796xEnableSlotCounter();
}
else
{
no_slots = 1; // 1 slot if bit is set
}
p_slot_no = &slot_no[0]; // slot number pointer
mask_size = (((length >> 2) + 1) >> 1); // mask_size is 1 for length = 4 or 8
buf[0] = 0x8F;
buf[1] = 0x91; // send with CRC
buf[2] = 0x3D; // write continuous from 1D
buf[5] = flags; // ISO15693 flags
buf[6] = 0x01; // anticollision command code
//optional afi should be here
if(flags & 0x10)
{
// mask_size is 2 for length = 12 or 16 ;
// and so on
size = mask_size + 4; // mask value + mask length + afi + command code + flags
buf[7] = afi;
buf[8] = length; // masklength
if(length > 0)
{
for(i = 0; i < mask_size; i++)
{
buf[9 + i] = *(mask + ((mask_size-1)-i));
}
}
fifo_length = 9;
}
else
{
// mask_size is 2 for length = 12 or 16
// and so on
size = mask_size + 3; // mask value + mask length + command code + flags
buf[7] = length; // masklength
if(length > 0)
{
for(i = 0; i < mask_size; i++)
{
buf[8 + i] = *(mask + ((mask_size-1)-i));
}
}
fifo_length = 8;
}
buf[3] = (char) (size >> 8);
buf[4] = (char) (size << 4);
Trf796xResetIrqStatus();
McuCounterSet(); // TimerA set
COUNT_VALUE = COUNT_1ms * 30; // 20ms
IRQ_CLR; // PORT2 interrupt flag clear
IRQ_ON;
Trf796xRawWrite(&buf[0], mask_size + fifo_length); // writing to FIFO
i_reg = 0x01;
irq_flag = 0x00;
START_COUNTER; // start timer up mode
while(irq_flag == 0x00)
{
} // wait for end of TX interrupt
for(j = 1; j <= no_slots; j++) // 1 or 16 available timeslots
{ rxtx_state = 1; // prepare the extern counter
// the first UID will be stored from buf[1] upwards
McuCounterSet(); // TimerA set
COUNT_VALUE = COUNT_1ms * 20;
START_COUNTER; // start timer up mode
irq_flag = 0x00;
while(irq_flag == 0x00)
{
} // wait for interrupt
while(i_reg == 0x01) // wait for RX complete
{
k++;
if(k == 0xFFF0)
{
i_reg = 0x00;
rx_error_flag = 0x00;
}
}
command[0] = RSSI_LEVELS; // read RSSI levels
Trf796xReadSingle(command, 1);
switch(i_reg)
{
case 0xFF: // if recieved UID in buffer
if(stand_alone_flag == 1)
{
found = 1;
}
else
{
#ifdef ENABLE_HOST
UartPutCrlf();
UartPutChar('[');
for(i = 3; i < 11; i++)
{
UartPutByte(buf[i]); // send UID to host
}
UartPutChar(',');
UartPutByte(command[0]); // RSSI levels
UartPutChar(']');
UartPutCrlf();
#endif
}
break;
case 0x02: // collision occured
if(stand_alone_flag == 0)
{
#ifdef ENABLE_HOST
UartPutChar('[');
UartPutChar('z');
UartPutChar(',');
UartPutByte(command[0]); // RSSI levels
UartPutChar(']');
#endif
}
p_slot_no++; // remember a collision was detected
*p_slot_no = j;
McuDelayMillisecond(5);
break;
case 0x00: // timer interrupt
if(stand_alone_flag == 0)
{
#ifdef ENABLE_HOST
UartPutChar('['); // send no-response massage to host
UartPutChar(',');
UartPutByte(command[0]); // RSSI levels
UartPutChar(']');
#endif
}
break;
default:
break;
}
Trf796xReset(); // FIFO has to be reset before recieving the next response
if((no_slots == 16) && (j < 16)) // if 16 slots used send EOF(next slot)
{
Trf796xStopDecoders();
Trf796xRunDecoders();
Trf796xTransmitNextSlot();
}
else if((no_slots == 16) && (j == 16)) // at the end of slot 16 stop the slot counter
{ Trf796xStopDecoders();
Trf796xDisableSlotCounter();
}
else if(no_slots == 1) // 1 slot is used
{
break;
}
if(stand_alone_flag == 0)
{
#ifdef ENABLE_HOST
//UartPutCrlf();
#endif
}
} // for
if(host_control_flag == 0)
{
if(found == 1) // LED on?
{
LED_15693_ON; // LEDs indicate detected ISO15693 tag
}
else
{
LED_15693_OFF;
LED_POWER_ON;
}
}
new_length = length + 4; // the mask length is a multiple of 4 bits
mask_size = (((new_length >> 2) + 1) >> 1);
while((*p_slot_no != 0x00) && (no_slots == 16) && (new_length < 61) && (slot_no[16] != 16))
{
*p_slot_no = *p_slot_no - 1;
for(i = 0; i < 8; i++)
{
new_mask[i] = *(mask + i); //first the whole mask is copied
}
if((new_length & BIT2) == 0x00)
{
*p_slot_no = *p_slot_no << 4;
}
else
{
for(i = 7; i > 0; i--)
{
new_mask[i] = new_mask[i - 1];
}
new_mask[0] &= 0x00;
}
new_mask[0] |= *p_slot_no; // the mask is changed
McuDelayMillisecond(2);
Iso15693Anticollision(&new_mask[0], new_length); // recursive call with new Mask
p_slot_no--;
}
IRQ_OFF;
} // Iso15693Anticollision
//===============================================================
// NAME: void TRF796xCheckRXWaitTime()
//
// BRIEF: a bug writes wrong value in register 0x07 "RX no response wait"
// this causes ISO15693 Anticollision to fail
//
// INPUTS:
//
// OUTPUTS:
//
// PROCESS: [1] read ISO register to check if low or high data rate
// [2] set correct value in register 0x07 "RX no response wait"
//
//
// CHANGE:
// DATE WHO DETAIL
// 3May2011 Andre Frantzke Bugfix
//===============================================================
void TRF796xCheckRXWaitTime(void)
{
u08_t MyRegister[2],write[2];
// [1] read ISO register to check if low or high data rate
MyRegister[0] = ISO_CONTROL;
MyRegister[1] = ISO_CONTROL;
Trf796xReadSingle (&MyRegister[1], 1);
//[2] set correct value in register 0x07 "RX no response wait"
if((MyRegister[1] < 0x02) || (MyRegister[1] == 0x04) || (MyRegister[1] == 0x05)) // low data rate
{
write[0] = RX_NO_RESPONSE_WAIT_TIME;
write[1] = 0x30; // 1812 us
Trf796xWriteSingle(write, 2);
}
else
{
write[0] = RX_NO_RESPONSE_WAIT_TIME;
write[1] = 0x14; // 755 us
Trf796xWriteSingle(write, 2);
}
}
/*
u08_t MyRegisters[30], MyTemp[2];
MyRegisters[0] = CHIP_STATE_CONTROL;
MyRegisters[1] = CHIP_STATE_CONTROL; // next slot counter
Trf796xReadSingle (&MyRegisters[1], 1);
MyRegisters[2] = ISO_CONTROL;
MyRegisters[3] = ISO_CONTROL; // next slot counter
Trf796xReadSingle (&MyRegisters[3], 1);
MyRegisters[4] = ISO_14443B_OPTIONS;
MyRegisters[5] = ISO_14443B_OPTIONS; // next slot counter
Trf796xReadSingle (&MyRegisters[5], 1);
MyRegisters[6] = ISO_14443A_OPTIONS;
MyRegisters[7] = ISO_14443A_OPTIONS; // next slot counter
Trf796xReadSingle (&MyRegisters[7], 1);
MyRegisters[8] = TX_TIMER_EPC_HIGH;
MyRegisters[9] = TX_TIMER_EPC_HIGH; // next slot counter
Trf796xReadSingle (&MyRegisters[6], 1);
MyRegisters[10] = TX_TIMER_EPC_LOW;
MyRegisters[11] = TX_TIMER_EPC_LOW; // next slot counter
Trf796xReadSingle (&MyRegisters[11], 1);
MyRegisters[12] = TX_PULSE_LENGTH_CONTROL;
MyRegisters[13] = TX_PULSE_LENGTH_CONTROL; // next slot counter
Trf796xReadSingle (&MyRegisters[13], 1);
MyRegisters[14] = RX_NO_RESPONSE_WAIT_TIME;
MyRegisters[15] = RX_NO_RESPONSE_WAIT_TIME; // next slot counter
Trf796xReadSingle (&MyRegisters[15], 1);
MyRegisters[16] = RX_WAIT_TIME;
MyRegisters[17] = RX_WAIT_TIME; // next slot counter
Trf796xReadSingle (&MyRegisters[17], 1);
MyRegisters[18] = MODULATOR_CONTROL;
MyRegisters[19] = MODULATOR_CONTROL; // next slot counter
Trf796xReadSingle (&MyRegisters[19], 1);
MyRegisters[20] = RX_SPECIAL_SETTINGS;
MyRegisters[21] = RX_SPECIAL_SETTINGS; // next slot counter
Trf796xReadSingle (&MyRegisters[21], 1);
MyRegisters[22] = REGULATOR_CONTROL;
MyRegisters[23] = REGULATOR_CONTROL; // next slot counter
Trf796xReadSingle (&MyRegisters[23], 1);
MyRegisters[24] = IRQ_STATUS;
MyRegisters[25] = IRQ_STATUS; // next slot counter
Trf796xReadSingle (&MyRegisters[25], 1);
MyRegisters[26] = IRQ_MASK;
MyRegisters[27] = IRQ_MASK; // next slot counter
Trf796xReadSingle (&MyRegisters[27], 1);
MyRegisters[28] = COLLISION_POSITION;
MyRegisters[29] = COLLISION_POSITION; // next slot counter
Trf796xReadSingle (&MyRegisters[29], 1);
*/
Hello Will,
There are timing differences between NXP SLI tags and TI Tag-It Transponders, typically concerning the amount of time until a tag replies to a command.
In the trf796x.c file, there is a function to set the registers, Trf796xWriteIsoControl
Find these lines in it (look around line 717):
if((iso_control < 0x02) || (iso_control == 0x04) || (iso_control == 0x05)) // low data rate
{
write[0] = RX_NO_RESPONSE_WAIT_TIME;
write[1] = 0x30; // 1812 us
Trf796xWriteSingle(write, 2);
}
else
{
write[0] = RX_NO_RESPONSE_WAIT_TIME;
write[1] = 0x14; // 755 us
Trf796xWriteSingle(write, 2);
}
The setting in the ELSE statement is what you want to change, the 0x14. In the TRF7970A BoosterPack code, it is set to 0x15 if I remember right, so try increasing that. I'd try 0x20 and see if that works just to give the tags more time.
I would usually try and track down the setting myself but I don't have NXP tags that collide that far in...
In the past, that setting was been the culprit, so tinker with it a bit and see if you get better results.
Hi Ralph,
I made modifications to the 'while block' which runs the recursive anti-collision call
along the lines of the TRF7970A BoosterPack and LaunchPack code. The GUI for
the TRF7960A EVM still does not report tags with collisions in the first 3 nibbles but
when I connect the firmware directly to a terminal and step through code I can see
the collisions are correctly resolved and then each of the tags are reported. This
along with adjusting the wait times solves the problem for me.
Many thanks,
Will