Heart rate monitors measure the heart rate during exercise or vigorous activity and gauge how hard the patient is working. Newer heart rate monitors consist of two main components: a signal acquisition sensor/transmitter and a receiver (wrist watch or smart phone). In some cases, the signal acquisition is integrated into fabric worn by the user or patient. MCUs analyze the ECG signal and determine the heat rate, while an 8-bit MCU can suffice for a simple heart rate monitor. For more complex analysis, such as heart rate variability, activity level and breathing rate, a high-end 32-bit MCU may be used. Furthermore, low power wireless technologies are used to allow the sensor to communicate to the receiver. Freescale offers 8-bit and 32-bit MCUs that are applicable across the entire spectrum of heart rate monitors. In addition, the Freescale portfolio includes inertial sensors or accelerometers for activity monitoring and ZigBee® and proprietary wireless solutions to enable communication between the sensors and the receiver. For more information go to freescale.com/APLHRM

    Curve22519 is a Montgomery elliptic-curve. Such as Apple HomeKit, most of network and IoT software use it in Diffie-Hellman algorithm for key exchanging.     On the Security Kinets MCU chip,if we use just the software algorithm (base on mbedTLS), Curve25519 will spend 180ms for calculation of the shared security.     It is faster than other 256bit elliptic-curve with software algorithm, Because of the shared security calculation will take more than 1200ms with a Weierstrass’s BP256R1curve when use software algorithm.     With LTC ECC HW acceleration, it take only 16ms to calculate the shared security on 256bit elliptic-curve. Whatever you do, the speed of hardware acceleration always faster than the software algorithm.     Now that we should also want to use the LTC to accelerate the Curve22519. The LTC, however, only supported Weierstrass form curve, but Curve22519 is a Montgomery curve…     Although, we can't use LTC in Curve22519 directly, we can use it by mapping it to a Weierstrass form to use it.  As below, we gave parameters of these curves, transform formulas, example code and test result to show how and why to do it. 1. Curve parameter:    Cuvre22519 in Montgomery form:    Y^2 = X^3 + A*X^2 + X    Fp = 0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffed    A= 486662    Gx = 9    Gy = 0x20ae19a1b8a086b4e01edd2c7748d14c923d4d7e6d7c61b229e9c5a27eced3d9    Order of G point  =  0x1000000000000000000000000000000014def9dea2f79cd65812631a5cf5d3ed      Cuvre22519 in Weierstrass form :    Y^2 = X^3 + a*X + b    Fp = 0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffed    a  =  0x2aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa984914a144L    b  =  0x7b425ed097b425ed097b425ed097b425ed097b425ed097b4260b5e9c7710c864L    Gx = 0x2aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaad245a    Gy = 0x20ae19a1b8a086b4e01edd2c7748d14c923d4d7e6d7c61b229e9c5a27eced3d9    Order of G point  =  0x1000000000000000000000000000000014def9dea2f79cd65812631a5cf5d3ed    2. Calculation formula:   x_w –  x-coordinate value in  Weierstrass form   y_w –  y-coordinate value in  Weierstrass form   x_m - x-coordinate value in  Montgomory form   y_m -  we don’t care y-coordinate value in  Weierstrass mode   a_m – a coefficient of Montgomery equation (   Y^2 = X^3 + a_m * X^2 + X)   a_w – a coefficient of Weierstrass equation (   Y^2 = X^3 + a*X + b )   b_w – a coefficient of Weierstrass equation (   Y^2 = X^3 + a*X + b )     a)  x_w = (x_m + a_m/3)  %  p     b)  y_w ^2 = x_w ^ 3 + a_w*x_w + b_w c)   x_m = (x_w - a_m/3) % p You could reference these document as below: https://en.wikipedia.org/wiki/Curve25519 https://en.wikipedia.org/wiki/Montgomery_curve 3. example code: // public and private at Montgomery end #define M255_d      "0x7178DAC11D42AA5F39B10A62A8584DB0C8864564ADC9DF84EC0B13D9AEC220F8" #define M255_Qx     "0x3BA5048381744348D84E754B9944ABE080B37F7D4158DCE60CD79F66B98AB89E" // public and private at Weierstrass end #define WTS255_d    "0x09CC5CCF43C656C1309EE5A3491D5A8361607CEEB0C9B2B31A575E0FEF2B8835" #define WTS255_Qx   "0x3F4BDE110EE7AF71EF428D1018D188E35BAFB019F34F84E6465C5194B363DC2D" #define WTS255_Qy   "0x7540577CE6F920354E2A9D38CE88847D7447E66FA4D188AC75CB63C17210B718" #define WTS255_Qx_TO_M255_Qx     "0x14A13366643D04C74497E2656E26DE38B105056F48A4DA3B9BB1A6EA08B6B7DC" #define AM_INV3                  "0x2aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaad2451" int ecdh_wts_curve_end( ) {     unsigned int ticks;     int ret = 0;     size_t blen = 0, blen_peer = 0;     ecdh_context ecdh;     ecdh_context ecdh_peer;   // to_wts255     ecdh_context ecdh_peer_m255;     mpi R;     mpi_init(&R);     ecdh_init( &ecdh);     ecdh_init( &ecdh_peer);     ecdh_init( &ecdh_peer_m255);     MPI_CHK(ecp_use_known_dp( &ecdh.grp, ECP_DP_WTS25519 ));     MPI_CHK(ecp_use_known_dp( &ecdh_peer.grp, ECP_DP_WTS25519 ));     MPI_CHK(ecp_use_known_dp( &ecdh_peer_m255.grp, ECP_DP_M255 ));     blen = set_hash_buff(/*TEST_ECP_GRP_ID*/ECP_DP_WTS25519, &secret_buf, ecp_name);     if(blen == 0) {         ret = -1;         goto cleanup;     }     mpi_read_string(&ecdh.d, 16,  WTS255_d);     mpi_read_string(&ecdh.Q.X, 16,  WTS255_Qx);     mpi_read_string(&ecdh.Q.Y, 16,  WTS255_Qy);     mpi_lset(&ecdh.Q.Z, 1);     mpi_read_string(&ecdh_peer_m255.d, 16, M255_d);     mpi_read_string(&ecdh_peer_m255.Q.X, 16, M255_Qx);     mpi_init(&ecdh_peer_m255.Q.Y);     mpi_lset(&ecdh_peer_m255.Q.Z, 1);     // map M255 point to WTS255 point     my_timer_start();     mpi_read_string(&R, 16, AM_INV3);         mpi_add_mpi(&ecdh_peer.Q.X, &ecdh_peer_m255.Q.X, &R);     mpi_mod_mpi(&ecdh_peer.Q.X, &ecdh_peer.Q.X, &ecdh_peer_m255.grp.P);        mpi_lset(&R, 3);     mpi_exp_mod (&ecdh_peer_m255.Q.Y , &ecdh_peer.Q.X, &R, &ecdh_peer_m255.grp.P, NULL);     mpi_mul_mpi(&R, &ecdh_peer.grp.A, &ecdh_peer.Q.X);     mpi_mod_mpi(&R, &R, &ecdh_peer.grp.P);          mpi_add_mpi(&ecdh_peer_m255.Q.Y, &ecdh_peer_m255.Q.Y, &R);     mpi_add_mpi(&ecdh_peer_m255.Q.Y, &ecdh_peer_m255.Q.Y, &ecdh_peer.grp.B);     mpi_mod_mpi(&ecdh_peer_m255.Q.Y, &ecdh_peer_m255.Q.Y, &ecdh_peer.grp.P);     mpi_mod_sqrt(&ecdh_peer.Q.Y, &ecdh_peer_m255.Q.Y, &ecdh_peer_m255.grp.P);     // z = 1     mpi_lset(&ecdh_peer.Q.Z, 1);     MPI_CHK(ecp_copy(&ecdh.Qp,  &ecdh_peer.Q));     MPI_CHK(ecdh_calc_secret_wts2mont( &ecdh, &blen, secret_buf, blen, myrand, NULL));     mpi_read_string(&R, 16, AM_INV3);         mpi_sub_mpi(&ecdh_peer_m255.Q.X, &ecdh.Q.X, &R);     mpi_mod_mpi(&ecdh_peer_m255.Q.X, &ecdh_peer_m255.Q.X, &ecdh_peer_m255.grp.P);     ticks = my_timer_stop();     // print out message     polarssl_printf("Weierstrass curve shared secutiy:\n");     mpi_printf_string( &ecdh.z, 16);     polarssl_printf("%s ecdh peer to peer: %lu ticks, %d ms (%d) \n", ecp_name , ticks, ticks / (CLOCK_SYS_GetPitFreq(0) / 1000),CLOCK_SYS_GetPitFreq(0) );     cleanup:     if( ret !=0 )         polarssl_printf( "%s test Unexpected error, return code = %08X\n", ecp_name, ret );     mpi_free(&R);     ecdh_free( &ecdh);     ecdh_free( &ecdh_peer);     ecdh_free( &ecdh_peer_m255);         return( 0 );    } int ecdh_mont_curve_end( ) {     int verbose = 1;     unsigned int ticks;     int ret = 0;     size_t blen = 0, blen_peer = 0;     ecdh_context ecdh;     ecp_point Q_peer;          // peer public point     ecdh_init( &ecdh);     ecp_point_init( &Q_peer);     MPI_CHK(ecp_use_known_dp( &ecdh.grp, ECP_DP_M255 ));     blen_peer = set_hash_buff(ECP_DP_M255, &secret_buf_peer, ecp_name);     if(blen_peer == 0) {         ret = -1;         goto cleanup;     }     mpi_read_string(&ecdh.d, 16,  M255_d);     mpi_read_string(&ecdh.Q.X, 16,  M255_Qx);     mpi_init(&ecdh.Q.Y);   // don't care Y, only init it     mpi_lset(&ecdh.Q.Z, 1);     mpi_read_string(&Q_peer.X, 16, WTS255_Qx_TO_M255_Qx);     mpi_init(&Q_peer.Y);     mpi_lset(&Q_peer.Z, 1);        MPI_CHK(ecp_copy(&ecdh.Qp,  &Q_peer));     my_timer_start();     MPI_CHK(ecdh_calc_secret( &ecdh, &blen_peer, secret_buf_peer, blen_peer, myrand, NULL));     ticks = my_timer_stop();     polarssl_printf("%s ecdh peer to peer: %lu ticks, %d ms (%d) \n", ecp_name , ticks, ticks / (CLOCK_SYS_GetPitFreq(0) / 1000),CLOCK_SYS_GetPitFreq(0) );     polarssl_printf("Montogemory curve shared secutiy:\n");     mpi_printf_string( &ecdh.z, 16);     polarssl_printf( "passed\n" );     cleanup:     if( ret !=0 && verbose != 0 )         polarssl_printf( "%s test Unexpected error, return code = %08X\n", ecp_name, ret );     ecdh_free( &ecdh);     ecp_point_free( &Q_peer);     if( verbose != 0 )         polarssl_printf( "\n" );         return( 0 );    } ‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍ 4. Test result: Test result of curv25519 in  Weierstrass form with LTC:     2. Test result of curve25519 in Montgomery form with software algorithm:      We could see that the shared security both in Weierstrass form with LTC and Montgomery form are “0x1454BDCD6A94D6336AA5A76F3CB40BBE12B65A2CDC9DA6B478948906638896D1”. But the calculation speed with LTC was ten times faster than other one.

How to byte program SPI flash via QSPI QSPI module are used in many Kinetis MCU, like K8x, K27/28 and KL8x. QSPI expands the internal flash range and can run in a fast speed. Compared to DSPI, QSPI is very complex and often takes a lot of time to learn. In KSDK there are two QSPI demo which shows how to program SPI flash in DMA mode and polling mode. Both of them program the QSPI flash with a word type array. But can the QSPI module program SPI Flash in byte? Yes, this article shows how to do it. Device: FRDM_KL82Z Tool: MCUXpresso IDE Debug firmware: JLINK I build the test project base on KL82 SDK/driver_example/qspi/polling_transfer. To byte program SPI flash, a new LUT item must be added. uint32_t lut[FSL_FEATURE_QSPI_LUT_DEPTH] =    {/* Seq0 :Quad Read */          /* CMD:       0xEB - Quad Read, Single pad */          /* ADDR:       0x18 - 24bit address, Quad pads */          /* DUMMY:     0x06 - 6 clock cyles, Quad pads */          /* READ:       0x80 - Read 128 bytes, Quad pads */        …        …        [32] = QSPI_LUT_SEQ(QSPI_CMD, QSPI_PAD_1, 0x02, QSPI_ADDR, QSPI_PAD_1, 0x18),        [13] = QSPI_LUT_SEQ(QSPI_WRITE, QSPI_PAD_1, 0x1, 0, 0, 0),        …        /* Match MISRA rule */        [63] = 0}; This item tells system how to program a single byte. Then when we write the data to TxBuffer, we must write the byte 4 times. This is because a write transaction on the flash with data size of less than 32 bits will lead to the removal of four data entry from Txbuffer. The valid bit will be used and the rest of the bits will be discard. Then before we start programming, we must set the data size.      QSPI_SetIPCommandSize(EXAMPLE_QSPI,1);   After byte program, we can see the result from 0x68000000. Attachment is the demo project. You can find that 0x03 was written to 0x68000005 after running.

This file contains some codewarrior code examples migrated from the IAR examples in the sample code package available at the freescale webpage: blink_blue blink_red blink_rgb serial_test_19200 serial_test_115200 touch_toggle_leds Regards

1. How Calibration works There are three main sub-blocks important in understanding how the Kinetis SAR module works.  There is a capacitive DAC, a comparator, and the SAR engine that controls the module. Of those blocks, the DAC is most susceptible to variations that can cause linearity problems in the SAR. The DAC is architected with three sets of binary weighted capacitors arrayed in banks, as in Figure 1. The capacitors that represent the most significant bits of the SAR (B15:B11) are connected directly to the inputs of the comparator. The next bank of five capacitors (B10:B6) is connected to the top plate of the MSB array through an intentionally oversized scaling capacitor. The final six capacitors that makeup the least significant bits of the SAR (B5:B0) are correspondingly connected to the top plate of the middle bank of capacitors through another scaling capacitor. Figure 1. Arrangement of DAC capacitors Only the MSB capacitor bank is calibrated. Because the first scaling capacitor is intentionally oversized, each of the non-calibrated MSB capacitors will have an effective capacitance too small to yield accurate results. However, because they are always too small, we can measure the amount oferror that each of those capacitors would cause individually, and add that back in to the result. Calibration starts with the smallest of the LSB capacitors, B11. The SAR samples Vrefl on all of the capacitors that are lower-than or equal-to the capacitor under test (CUT), while connecting all of the smaller capacitors to Vrefh. The top plate of all of the MSB capacitors is held at VDDA while this happens. After the sampling phase is complete, the top plates of the MSB capacitors are allowed to float, and the bottom plates of the MSBs not under test are connected to Vrefl. This allows charge to redistribute from the CUT to the smaller capacitors. Finally, an 11 bit SAR algorithm (corresponding with the 11 capacitors that are smaller than the MSB array) is performed which produces a result that indicates the amount of error that the CUT has compared to an ideally sized capacitor. This process is repeated for each of the five MSBs on both the plus side and minus side DACs and the five error values that are reported correspond to the five MSBs accordingly. All of these error values are about the same magnitude, with a unit of 16-bit LSBs. See Figure 2 for an example. Figure 2. Example of calibration on bit 11 The DAC MSB error is cumulative. That is, if bit 11 of the DAC is set, then the error is simply the error of that bit. However if bit 12 of the DAC is set, the total error is equivalent tothe error reported on bit 12, plus the error reported on bit 11. For each MSB the error is calculated as below, where Ex is the error found during the calibration for its corresponding MSB bit: When bit 11 of the DAC is set: CLx0 = E0. When bit 12 of the DAC is set: CLx1 = E0+E1. When bit 13 of the DAC is set: CLx2 = E2 + E1 + 2E0. When bit 14 of the DAC is set: CLx3 = E3 + E2 + 2E1 + 4E0. When bit 15 of the DAC is set: CLx4 = E4 + 2E3 + 4E2 + 8E1 + 16E0 Figure 3. Effect of calibration error on ADC response These are the values that are then placed in each of the CLxx calibration results registers. Figure 3 shows how the errors would accumulate if all of the CLxx registers were set to zero. The offset and gain registers are calculated based on these values as well. Because of this, the gain and offset registers calibrate only for errors internal to the SAR itself. Self calibration does not compensate for board or system level gain or offset issues. 2. Recommended Calibration Procedure From the above description it is evident that the calibration procedure is in effect several consecutive analog to digital conversions. These are susceptible to all of the same sources of error of any ADC conversion. Because what is primarily being measured is the error in the size of the MSB capacitors; the recommendation is to configure the SAR in such a way as to make for the most accurate conversions possible in the environment that the SAR is being calibrated in. Noise is the primary cause of run-to-run variation in this process,so steps should be taken to reduce the impact of noise during the calibration process. Such as: All digital IO should be silent and unnecessary modules should be disabled. The Vrefh should be as stable and high a voltage as possible, since higher Vrefh means larger ADC code widths. An isolated Vrefh pin would be ideal. Lacking that, using an isolated VDDA as the reference would be preferable to using VREFO. The clock used should be as noise free as possible, and less than or equal to 6 MHz. For this purpose the order of desirable clock sources for calibration would be OSC > PLL > FLL > ASYNC The hardware averaging should be set to the maximum 32 samples. The Low Power Conversion bit should be set to 0. The calibration should be done at room temperature. The High Speed Conversion and Sample Time Adder will not have much effect in most situations, and the Diff and Mode bits are completely ignored by the calibration routine. The calibration values should be taken for each instance of the SAR on a chip in the above conditions. They should be stored in nonvolatile memory and then written into their appropriate registers whenever the ADC register values are cleared. In some instances, the system noise present will still cause the calibration routine to exhibit greater than desired run-to-run variation. One rule of thumb would be to repeat calibration several times and look at the CLx0 registers. If the value reported in that register varies by more than three, the following procedure can be implemented. Run the calibration routine several times. Twenty to forty times. Place the value of each of the calibration registers into a corresponding array. Perform a bubble sort on each array and find the median value for each of the calibration registers. Use  these median values as described for typical calibration results.

Hi, I have a project created by Processor Expert and CodeWarrior 10.2 for TWR-K20 demo kit. Becasue I have some problem to use the Processor Expert USB HID Keyboard Host of the USB stack 4.1.1, I need to change to add the non-PE USB HID Keyboard Host into the project. Can anyone tell me how to do it? It will be very appreciated to give me a simple 'PE' example project, and add the non-PE USB HID keyboard host stack. Thank you! Stanley

Hello Kinetis community. Attached there is a guide on how to modify an existing KDS project to be loaded using the KBOOT Flash Resident bootloader. Basically it explains 2 procedures: 1- Manipulating linker file to move application and vectors. 2- Adding data for the Bootloader Configuration Area (BCA). I am also including 3 adapted KDS v3.0.0 example projects ready to be used with KBOOT Flash Resident bootloader in a FRDM-K22F: - Baremetal project. - KSDK project. - KSDK project with Processor Expert support. The application simply toggles the red, green and blue LEDs sequentially. I hope you find the document and projects useful! Regards! Jorge Gonzalez

Latest version of the AN2295 universal bootloader includes support for IAR 7.6 IDE. - added support for Kinetis E MCUs - Kinetis K,L,M,E,W,V support

This document explains a potential issue where interrupts appear to be disabled after enterring debug mode. This is as a result of the NMI being active when debug is enabled.

Hey there Kinetis lovers!  We in the Systems Engineering team for Kinetis Microcontrollers see all kinds of situations that customers get into, and none can be particularly troubling like how the reset pin is handled.  The purpose of this document is to provide a list of Frequency Asked Questions (FAQ) that we get here in the Kinetis Systems Engineering department.  This is intended to be a living list and as such, may in no way be complete.  However we hope that you will find the below questions and answers useful.   Q:  Do I need to connect the reset signal to be able to debug a Kinetis device?   This is a commonly asked question. Strictly speaking, you do not need to connect the device reset line of a Kinetis device to the debug connector to be able to debug. The debug port MDM-AP register allows the processor to be held in reset by means of setting the System Reset Request bit using just the SWD_CLK and SWD_DIO lines.   However, before deciding to omit the reset line from your debug connector you should give some careful thought to how this may impact the ability to program and debug the device in certain scenarios. Does the debugger/flash programmer or external debug pod require the reset pin? It may be that the specific tool you are using only supports resetting the device by means of the reset line and does not offer the ability to reset the device by means of the MDM-AP. Have you changed the default function of the debug signals? You may need to use the SWD_CLK and/or the SWD_DIO signals for some other function in your application. This is especially true in low pin count packages. Once the function is changed (by means of the PORTx_PCRy registers) you will no longer have access to the MDM-AP via those signals. If you do not have access to the reset signal then you have no way of preventing the core from executing the code that will disable the SWD function of the pins. So you will not be able to re-program the device. In order to prevent this type of situation you need to either: Setup your code to change the function of the SWD pins several seconds after reset is released so that the debugger can halt the core before this happens. Put some kind of “backdoor” mechanism in your code that does not re-program the SWD function, or re-enables the SWD function, on these pins. For example, a specific character sequence sent via a UART or SPI interface.   Some Kinetis devices allow the reset function of the reset pin to be disabled. In this case you can only use the SWD signals as a means of resetting the device via the MDM-AP. If you change the SWD pin function in addition to disabling the reset pin then you must provide a backdoor means of re-enabling the SWD function if you want to be able to reprogram the device.

You can put the code directory in the SDK_2.6.0_FRDM-K64F\boards\frdmk64f to use. 1、Introduction As is known to all, we use debugger to download the program or debug the device. FRDMK64 have the opsenSDA interface on the board, so wo do not need other’s debugger. But if we want to design a board without debugger but can download the program, we can use the bootloader. The bootloader is a small program designed to update the program with the interface such as UART,I2C,SPI and so on. This document will describe a simple bootloader based on the FRDMK64F.The board uses SD card to update the application. User can put the binary file into the card. When the card insert to the board ,the board will update the application automatically. The bootloader code and application code are all provided so that you can test it on your own board.   2、Bootloader’s implementation   The schematic for SD card is shown below. The board uses SDHC module to communicate with SD card.                                                  Figure 1.Schematic for SD card   We use the 2.6.0 version of FRDM-K64F’s SDK.You can download the SDK in our website. The link is “mcuxpresso.nxp.com”. The bootloader uses SDHC and fafts file system. So we should add files to support it.                   Figure 2.The support file   In main code, the program will wait until the card has inserted. Then it will find the file named “a000.bin” in sd card to update the application. If the file do not exist, the board will directly execute the application. If there is no application, the program will end. The following code shows how the program wait for inserting sd card. It will also check if the address has the application’s address.                      Figure 3.The code -- wait for inserting card   The following code shows how the program opens the binary file. If sd card doesn’t have the file, the program will go to the application. Figure 4.Open the binary file   If the program opens the file normally, the update will begin. It will erase 200k’s space from 0xa000. You can adjust it according to your project. Now I will explain update’s method in detail. Our data is written to the buffer called “rBUff”. The buffer size is 4K. Before write data to it, it is cleared.  Please note that when we erase or program the flash, we should disable all interrupts and when the operations finish we should enable the interrupts.  The file size will decide which way to write the data to flash.  1、If the size < 4k ,we just read the file’s data to buffer and judge if its size aligned with 8 byte. If not , we increase the size of “readSize” to read more data in our data buffer called “rBuffer”. The more data we read is just 0.    2、If the size > 4K, we use “remainSize” to record how much data is left. We read 4k each time until its size is smaller than 4k and then repeat step 1. When finish the operation at a  time, we should clear the buffer and increase the sector numer to prepare the next transmission. Figure 5.Write flash operation code   The way to clear the space is shown in the figure. It will initialize the flash and erase the given size from the given address.  “SectorNum” is used to show which sector to erase. Figure 6.Erase operation code   The following figure shows how to write the data to flash.              Figure 7.Program operation code    Before we go to the application, we should modify the configuration we did in the bootloader.     Close the systick, clear its value.     Set the VTOR to default value.     Our bootloader runs in PEE mode. So we should change it to FEI mode.     Disable the all pins. You should disable the global interrupt when run these codes. And don’t forget to enable the global interrupt. Figure 8.Deinitalization code   Then we can go to the application. Figure 9.Go to Application   3、Memory relocation The FRDMK64 has the 1M flash, from 0x00000000 to 0x00100000.As shown in figure 10,we use the 0xa000 as the application’s start address.            Figure 10.The memory map   Now, I will show you how to modify the link file for user application in different IDE. In IAR                                    Figure 11.IAR’s ICF In MDK Figure 12.MDK’s SCF   In MCUXpresso Figure 13.MCUXpresso’s flash configuration 4、Run the demo 1) Download the bootloader first. 2) Prepare a user application program. We use the “led blinky” as an example. 3) Modify the Link file. 4) Generate the binary file with your IDE, please name it as “a000.bin”. 5) Put it into the sd card like figure 5. Figure 14.SD card’s content        6) Insert the card. And power on. Wait for a moment, the application will execute automatically. 5、Reference 1) Kinetis MCU的bootloader解决方案 2) KEA128_can_bootloader