topic Re: RF Transmiter FXTH87 Power consumption and reset issues in Sensors

RF Transmiter FXTH87 Power consumption and reset issues

juansebastian16 — Tue, 03 Feb 2026 21:35:46 GMT

Hello everyone! and thanks in advance for reading!

I have been working on the FXTH87 Tire pressure sensor but I have a problem first of all about Reset sources, because I am counting with the Z axis accelerometer every time it turns around (spinning), but for any reason the register that count it, suddenly returns to zero (chip reset!). I have worked, to solve this, over the COP timer and the Periodic hardware (PRST), Reset sources, but nothing change.

In the other hand, I have measured the power consumption on chip and I got 5mA with RF and UUMA peripherals ON, and 1,48mA in STOP1 MODE doing nothing on code! so that is sooo much! I don't know whether the problem of reset is generated in a problem in the chip about power, voltage,... I am using a power supply voltage and works fine but maybe the chip have problems in power consumption and forces it reset itself.

Thanks in advance!

Re: RF Transmiter FXTH87 Power consumption and reset issues

juansebastian16 — Wed, 14 Feb 2018 21:57:55 GMT

I am focusing on Reset sources, and the only 2 Reset sources that I have problems are "illegal Address" and "Low Voltage Detect". The first one (illegal Address) is the more responsible about Resets. If I don't use a Firmware subroutine like "u8Status=TPMS_READ_ACCEL_Z(UUMA,2,0,7);", the Reset problem is solved... But you know this is not a solution...

I've communicated this chip with a receiver RFM69HCW, but the only thing I need is that the chip does not reset itself.

Re: RF Transmiter FXTH87 Power consumption and reset issues

juansebastian16 — Fri, 16 Feb 2018 20:55:38 GMT

Somebody know how to get the measurements WITHOUT Firmware Calls?

Re: RF Transmiter FXTH87 Power consumption and reset issues

david_diaz — Wed, 14 Mar 2018 22:15:41 GMT

Hello Juan,

Please review the information below for a better understanding of the issue:

- Are you using the TPMS FXTH87 Reference Project LF RF Communication CW10?

- Have you considered to use the Schematic TPMS FXTH870911 315MHz as a reference for your device connections?

- Could you please read the SRS register? Could you please share your results?

Regards,

David

Re: RF Transmiter FXTH87 Power consumption and reset issues

juansebastian16 — Tue, 03 Apr 2018 15:39:10 GMT

Hi and thank you!

Yes, I am using the TPMS FXTH87 Reference Project LF RF Communicaion CW10 now, because before I was using a library called ¨firmware.h¨ but now with this code example the reset was solved but I have another problem... The chip is not executing the code after turning off the chip, I mean, the code works good in transmition and there is not reset problem but I turn off the power supply and the turn it on and the code is not working now.

Because I transmit in 433 MHz I am using the Schematic TPMS FXTH87 434MHz (Figure 2-2. Typical reference demonstrator for FXTH87 434 MHz // from PDF FXTH87EDRM)... or should I use the Typical reference demonstrator for FXTH87 315 MHz??

About power consumption, I still have the same problem, In Stop1 mode and peripherals and GPIO off the chip consume around 2 mA and it should be, at least, 15 uA, please help me sloving this, with that consumption it is impossible to implement.

Thank you in advance!

This is the code I´m using

******************************************************************************  *   * TPMS FXTH87 LF RF Communication  * Data received by LF is processed  * The RF frame format and RF settings are compatible with the MKW01 receiver.   *   * user_configuration.h : contains the demo parameters configurable by the user  *   * MKW01_Communication.c : contains functions to process LF frame received and  * execute commands accordingly  *     ******************************************************************************/  /*  ******************************************************************************  *  *  Main.c - Code will reside in here.  *  ******************************************************************************  */ #include <hidef.h>                   /* for EnableInterrupts macro       */ #include "derivative.h"              /* include peripheral declarations  */ #include "main.h"                    #include "user_configuration.h" #include "dal.h"                      #include "szk_lf_data_detect.h" #include "szk_ff_tpm.h" #include "MKW01_Communication.h" #include "LED.h"  /*  ******************************************************************************  *  *                                  M A I N  *                          *            Choose demo parameters in user_configuration.h        *  ******************************************************************************  */  /* Be careful: LED5 and LED6 are driven by PTB0 and PTB1 which are also used in priority by the LF block   * So when the LF block is ON, LED5 and LED6 cannot be used.  * Choose in user_configuration.h to use LEDs or not.  */  unsigned long i=0; unsigned int c=0; int PACCZ=0,PACCX=0,P=0; UINT8 RESET @ 0x1800; UINT16 Z=0;  UINT8 u8Status=0x00; UINT16 gu16UUMA[5];// @ 0x01A1; UINT16 u16CompPressure; UINT16 u16CompAccelZ; UINT16 FrameID; UINT32 Tire_ID; UINT8 Firmware_Version; UINT8 Derivative_Descriptor; UINT8 TPMS_ID[6]; UINT8 LFDatagram[5]; UINT16 u16CompAccelX;  //UINT8  TPMS_CONT_ACCEL_GV  @ 0x008Eu; /* Embedded Firmware maps this location */ //UINT8  TPMS_INTERRUPT_FLAG @ 0x008Fu; /* Embedded Firmware maps this location */  UINT32 vueltas=0;   ///////////////////////////////////////////////////////////////////////////////////////////////////////////  UINT8 au8RFDataForCS[15] @ 0x0091; // Maximum length is 32 bytes; size of the RF buffer (in bytes)  void vfnSetupMCU(void); void RF_Setup(void); void InitTPM1CH0(void); void Send_RF_Datagram(void); void Code_Manchester_Frame(unsigned char *ptr); void vfnSetSTOPMode(UINT8 u8Mode); void tire_ID(void); void Init_LF(void); void Decode_LF_Datagram(void); void vfnSetPWU(void);  void main(void) {      UINT8 u8LFCount;      UINT8 u8LFFirst; //     DisableInterrupts;      u8LFFirst = LFDATA;       /* Config GPIO for setup */      vfnSetupGPIO();            vfnSetupMCU();          vfnSetPWU();          RF_Setup();i=0;        while(i<200){i++;}i=0;  // 5000(400ms)  -- 12500(1s)        tire_ID();        vueltas=0;PACCZ=0;PACCX=0;c=0; //       EnableInterrupts;      for (;;) {           __RESET_WATCHDOG();     /* feeds the dog */////////////////////////////////////////////////////////////////////////////////////////               RESET = CLEAR; //              while(i<10000){i++;}i=0;  // 5000(400ms)  -- 12500(1s) //              c++;                //              while(i<10000){i++;}i=0;  // 5000(400ms)  -- 12500(1s) //              c++;               RFCR2=0x0E; RFCR7_RFIACK = SET; //              u8Status=TPMS_READ_VOLTAGE(gu16UUMA); u8Status=TPMS_READ_TEMPERATURE(gu16UUMA);                    u8Status=TPMS_READ_PRESSURE(gu16UUMA,4); //          u8Status=TPMS_READ_ACCEL_X(gu16UUMA,2,0,7);           u8Status=TPMS_READ_ACCEL_Z(gu16UUMA,2,0,7); //TPMS_READ_ACCEL_Z(gu16UUMA,2,0,7);           u8Status=TPMS_COMP_PRESSURE(&u16CompPressure,gu16UUMA);           P=u16CompPressure>>1;           u8Status=TPMS_COMP_ACCEL_Z(&u16CompAccelZ,gu16UUMA); //TPMS_COMP_ACCEL_Z(&u16CompAccelZ,gu16UUMA);           PACCZ=u16CompAccelZ>>1;           Z=gu16UUMA[4];  // Z=gu16UUMA[4];            //          u8Status=TPMS_READ_ACCEL_X(gu16UUMA,2,0,7);  //TPMS_READ_DYNAMIC_ACCEL_Z(1,&u8Offset,UUMA); //        u8Status=TPMS_COMP_ACCEL_X(&u16CompAccelX,gu16UUMA); //         PACCX=u16CompAccelX>>1;           while(Z<315) //<27          Z<315      //  Z<309 (X)               { //                   DisableInterrupts;                    RFCR2=0x0E; RFCR7_RFIACK = SET;  // Clear all Flags            //         RESET = CLEAR;__RESET_WATCHDOG();     /* feeds the dog */ //               u8Status=TPMS_READ_VOLTAGE(gu16UUMA); u8Status=TPMS_READ_TEMPERATURE(gu16UUMA);                u8Status=TPMS_READ_PRESSURE(gu16UUMA,4); //               u8Status=TPMS_READ_ACCEL_X(gu16UUMA,2,0,7);                   u8Status=TPMS_READ_ACCEL_Z(gu16UUMA,2,0,7);  //TPMS_READ_ACCEL_Z(gu16UUMA,2,0,7);                   u8Status=TPMS_COMP_ACCEL_Z(&u16CompAccelZ,gu16UUMA); //TPMS_COMP_ACCEL_Z(&u16CompAccelZ,gu16UUMA);                   PACCZ=u16CompAccelZ>>1; // PTBD=1; //X=UUMA[3];           Z=gu16UUMA[4];  // Z=gu16UUMA[4]; //                  while(i<200){i++;}i=0;  // 5000(400ms)  -- 12500(1s) ///////////                   Send_RF_Datagram();TPMS_RF_WRITE_DATA_REVERSE(sizeof(au8RFDataForCS), &au8RFDataForCS[0u], 0);           //        TPMS_RF_READ_DATA_REVERSE(sizeof(READBuff), &READBuff[0], 0);           //        while(i<350){i++;}i=0;  // 5000(400ms)  -- 12500(1s) ///////////                   RFCR2 = 0x8E;           //        TPMS_RF_SET_TX(119);                   while(i<500){i++;}i=0;  // 5000(400ms)  -- 12500(1s) //////// i<400               }                              while(Z>295) //>17      Z>295       // Z>295 (X)               {           //         DisableInterrupts;                    RFCR2=0x0E; RFCR7_RFIACK = SET;  // Clear all Flags            //         RESET = CLEAR;__RESET_WATCHDOG();     /* feeds the dog */ //                   u8Status=TPMS_READ_VOLTAGE(gu16UUMA); u8Status=TPMS_READ_TEMPERATURE(gu16UUMA);                    u8Status=TPMS_READ_PRESSURE(gu16UUMA,4); //                   u8Status=TPMS_READ_ACCEL_X(gu16UUMA,2,0,7);                   u8Status=TPMS_READ_ACCEL_Z(gu16UUMA,2,0,7);  //TPMS_READ_ACCEL_Z(gu16UUMA,2,0,7);                   u8Status=TPMS_COMP_ACCEL_Z(&u16CompAccelZ,gu16UUMA); //TPMS_COMP_ACCEL_Z(&u16CompAccelZ,gu16UUMA);                   PACCZ=u16CompAccelZ>>1; // PTBD=0; //Z=UUMA[4];           Z=gu16UUMA[4];  // Z=gu16UUMA[4]; //                  while(i<200){i++;}i=0;  // 5000(400ms)  -- 12500(1s) ///////////                   Send_RF_Datagram();TPMS_RF_WRITE_DATA_REVERSE(sizeof(au8RFDataForCS), &au8RFDataForCS[0u], 0);           //        TPMS_RF_READ_DATA_REVERSE(sizeof(READBuff), &READBuff[0], 0);           //        while(i<350){i++;}i=0;  // 5000(400ms)  -- 12500(1s) ///////////                   RFCR2 = 0x8E;           //        TPMS_RF_SET_TX(119);                   while(i<500){i++;}i=0;  // 5000(400ms)  -- 12500(1s) //////// i<400               }               vueltas++; //// Turn it around                  } }  /*  ******************************************************************************  *  *                        vfnSetSTOPMode  *  ******************************************************************************  */ void vfnSetSTOPMode(UINT8 u8Mode) {      /*       Table 3-1. Stop Mode Selection       SIMPOT1  SPMSC2   SPMSC1        BDCSCR       STOPE    PDC      LVDE & LVDSE  ENBDM   Stop Mode       0       x        x             x      Stop modes disabled; illegal opcode reset if STOP instruction executed       1       1        0             0      Stop1       1       x        1             x      Stop4       1       x        x             1      Stop4 with BDM       */      if (u8Mode == STOP1 ) {           SPMSC2 |= SPMSC2_PDC_MASK;           SPMSC1 = (SPMSC1 | SPMSC1_LVDE_MASK)                     & (UINT8) (~((UINT8) (SPMSC1_LVDSE_MASK | SPMSC1_BGBE_MASK)));      } else if (u8Mode == STOP4 ) {           SPMSC2 |= SPMSC2_PDC_MASK;           /* Use BGBE for accurate ADC measurements */           SPMSC1 |= (SPMSC1_LVDSE_MASK | SPMSC1_LVDE_MASK | SPMSC1_BGBE_MASK);      } else {           /* Do nothing */      } } /*  ******************************************************************************  *  *                        vfnSetPWU  *  ******************************************************************************  */ void vfnSetPWU(void) {      /* Configure PWU for a periodic wake-up */      PWUCS0 = 0x1Fu;      PWUCS1 = CLEAR;      PWUDIV = 0x1Fu;       return; }  /*  ******************************************************************************  *  vfnSetupGPIO  ******************************************************************************  */ void vfnSetupGPIO(void) {       // All GPIOs are inputs      PTADD = 0x00;      PTBDD = 0x00;       //     SIMOPT1 = 0X33;//0x33//Disable WDT, Enable Debug BDM, Stop Enable, RF (DIS)(En)able.   0x23(RF Disable)  0x21(No Debug) //            SIMOPT2 = 0X00; // 0x00 Clock BUSCLK 4Mhz   // 0X73  //0X03 //       /*BUSCLKS 00 bUS fREQUENCY = 4Mhz*/ //            SRS = 0x00; //            PWUCS1 = 0x00;       return; }  /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// void vfnSetupMCU(void)//Archivos de configuracion inicial del FXTH87 Puerto D como salida puerto D apagado y configuracion inicial de registros {        SIMOPT1 = 0X33;//0x33//Disable WDT, Enable Debug BDM, Stop Enable, RF Enable.   0X13  0x11 ////// 0X31        SIMOPT2 = 0X00; // 0x00 Clock BUSCLK 4Mhz  //  0X70   /*BUSCLKS 00 bUS fREQUENCY = 4Mhz*/ //       SRS = 0x00; //       PWUCS1 = 0x00; }  void RF_Setup(void) { //     DisableInterrupts; //      TPMS_RF_ENABLE(1);          RFCR0 = 0x33;      //0x33 Data sent to 9615.4 bps          //  0x19 (19230.8 bps)          RFCR1 = 0x77;    //0x64 set to 38 for 56 bits          RFCR2 = 0x0E;    // RF Transmission OFF - No EOM - Pout=8dBm    - RPAGE=0                          // 00001110    0x14 //         RFCR2 = 0x8E;  //RF Transmission ON - No EOM - Pout=8dBm    - RPAGE=0                                       0x94              RFCR3 = 0x00;    //0x00 RF Output Low - RF Power UP - One Frame Transmitted                          // 00000000              RFCR4 = 0x05;     //0x05 Interframe timing set to 5ms /////////////////////////////////////////////////////////////////////              RFCR5 = 0x00;     //0x80 No Pseudo-random number used VCO highest power consumption level              RFCR6 = 0x01;     //VCO highest Power - interframe timing                          // was 00              RFCR7 = 0x00;     // RF Interrupt (Dis)Enabled - LVD Disable - RFM Not reset               // fDATA0=fXTAL x ((12 + 4 x CF) + AFREQ/8192)              //       = 26MHz x((12 + 4 x 1) + 5644 (10110000 01100) /8192)       /// 5009 (10011101 10001) 431.8977MHz              //       = 433.9131               // fDATA1=fXTAL x ((12 + 4 x CF) + BFREQ/8192)              //       = 26MHz x((12 + 4 x 1) + 5674 (10110001 01010) /8192)       /// 5041 (10011100 10001) 432.0024MHz              //       = 434.0083                // 434.0083 - 433.9131 = 47.6kHz  (x2 95.2 kHz)               /* 434MHz */             PLLCR0=0x9D;// 0xB0 1011 0000                                                              // 0x9D (431.8977MHz)                             //  AFREQ[12:5]              PLLCR1=0x8E;// 0x62  01100    0   10                                                       // 0x8E (431.8977MHz) (POL=1)  8A (POL=0)                             //  AFREQ[4:0] POL CODE[1:0]                              PLLCR2=0x9C;// 0xB1 10110001                                                               // 0x9C (432.0024MHz)              PLLCR3=0x8E;// 0x56 01010 110  CF=1 434MHz   MOD=1 FSK   CKREF=0 DX signal not generated   // 0x8E (432.0024MHz)          //PLLCR3=0x54;   // 01010 100  CF=1 434MHz   MOD=0 OOK   CKREF=0 DX signal not generated               //        EnableInterrupts; }  void InitTPM1CH0(void) { TPM1SC=0x08 | 0x02;// 4F CLOCK TIMER = FBUS=8MHz/128 - set Timer ON TPM1C0SC=0x00; //Configure in TBM , Interrupt Enable address TPM1MODH=0xFF; // FF Fixed the OC every 1.13sec TPM1MODL=0xFF;// FF Fixed the OC every 1.13sec }  void Send_RF_Datagram(void) { //unsigned char i; //DisableInterrupts; /* Specific data’s for MC33696 */      au8RFDataForCS[0]=0xAA;      au8RFDataForCS[1]=0xAA; // AA 10101010 needed to understain that the rest are DATA’s      au8RFDataForCS[2]=0xAA;  // (UINT8) (vueltas >> 24u); //       /* End of Specific data’s for MC33696 */      au8RFDataForCS[3]=(UINT8) (u16CompPressure >> 8u); // Pressure kPA      au8RFDataForCS[4]=(UINT8) (u16CompPressure);       // Pressure kPA      au8RFDataForCS[5]=0xAA;            au8RFDataForCS[6]=(UINT8) (vueltas >> 16u); //            au8RFDataForCS[7]=(UINT8) (vueltas >> 8u);      au8RFDataForCS[8]=(UINT8) (vueltas);      au8RFDataForCS[9]=(UINT8) (Tire_ID >> 24u);                // Tire ID      au8RFDataForCS[10]=(UINT8) (Tire_ID >> 16u);           // Tire ID      au8RFDataForCS[11]=(UINT8) (Tire_ID >> 8u);                   // Tire ID      au8RFDataForCS[12]=(UINT8) (Tire_ID);                      // Tire ID      au8RFDataForCS[13]=0xAA; // (UINT8) (vueltas >> 24u); //        au8RFDataForCS[14]=0xAA; //au8RFDataForCS[15u]=(UINT8) (PACCZ); //au8RFDataForCS[16u]=0xAA; //RFD21=Tx; //RFD32=Tx; InitTPM1CH0(); //RFCR7_RFIACK=1; // Clear all Flags //while(i<2500){i++;}i=0;  // 5000(400ms)  -- 12500(1s) //EnableInterrupts; }  void tire_ID(void) {      TPMS_READ_ID (TPMS_ID); // execution time = 512µs      Firmware_Version = TPMS_ID[0];      Derivative_Descriptor = TPMS_ID[1];      Tire_ID = 0;      Tire_ID |= TPMS_ID[2];      Tire_ID <<= 8;      Tire_ID |= TPMS_ID[3];      Tire_ID <<= 8;      Tire_ID |= TPMS_ID[4];      Tire_ID <<= 8;      Tire_ID |= TPMS_ID[5]; }  ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////  /*  ******************************************************************************  *  *  End of file.  *  ******************************************************************************  */

Re: RF Transmiter FXTH87 Power consumption and reset issues

david_diaz — Tue, 10 Apr 2018 21:57:34 GMT

Hello Juan,

I am glad to know that the reset issue is solved.

- Once the reference project mentioned before is downloaded, please review the follow the guide attached to this response. The Chapter 2 shows how to program the device. Could you please follow such guide and share your results once the device is flashed?

- You may keep using the typical reference demonstrator for FXTH87 at 434 MHz mentioned on the Reference Design. Please let me know if you have any further complication.

- The STOP1 refers to a power down of most internal circuits, including RAM, for maximum power savings; voltage regulator in standby. Such current, 15uA is too much. Could you please give us a brief description of your measurement procedure?

Please review the chapter 17.4 from datasheet to review the power consumptions based on the power mode.

I hope this information helps.

Regards,

David

Re: RF Transmiter FXTH87 Power consumption and reset issues

f20150335 — Mon, 24 Sep 2018 04:46:12 GMT

Hi Juan, can you please explain the method you used for measuring these currents? How are you measuring the power consumption? Are you logging the current values somewhere?

Re: RF Transmiter FXTH87 Power consumption and reset issues

kunzler_luis — Tue, 17 Sep 2019 19:28:06 GMT

Hi Juan,

I am trying the same and I am getting the same problem. How do you resolve that? (measure the spinning)

Thanks =)