Revised to disable BLE for radio communication as needed.
Dependencies: BLE_API nRF51822 mbed-dev-bin
Diff: source/core/MicroBitDevice.cpp
- Revision:
- 1:8aa5cdb4ab67
- Child:
- 47:69f452b1a5c9
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/source/core/MicroBitDevice.cpp Thu Apr 07 01:33:22 2016 +0100 @@ -0,0 +1,375 @@ +/* +The MIT License (MIT) + +Copyright (c) 2016 British Broadcasting Corporation. +This software is provided by Lancaster University by arrangement with the BBC. + +Permission is hereby granted, free of charge, to any person obtaining a +copy of this software and associated documentation files (the "Software"), +to deal in the Software without restriction, including without limitation +the rights to use, copy, modify, merge, publish, distribute, sublicense, +and/or sell copies of the Software, and to permit persons to whom the +Software is furnished to do so, subject to the following conditions: + +The above copyright notice and this permission notice shall be included in +all copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL +THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING +FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER +DEALINGS IN THE SOFTWARE. +*/ + +/** + * Compatibility / portability funcitons and constants for the MicroBit DAL. + */ +#include "MicroBitConfig.h" +#include "MicroBitButton.h" +#include "MicroBitDevice.h" +#include "MicroBitFont.h" +#include "mbed.h" +#include "ErrorNo.h" + +/* + * The underlying Nordic libraries that support BLE do not compile cleanly with the stringent GCC settings we employ + * If we're compiling under GCC, then we suppress any warnings generated from this code (but not the rest of the DAL) + * The ARM cc compiler is more tolerant. We don't test __GNUC__ here to detect GCC as ARMCC also typically sets this + * as a compatability option, but does not support the options used... + */ +#if !defined(__arm) +#pragma GCC diagnostic ignored "-Wunused-function" +#pragma GCC diagnostic push +#pragma GCC diagnostic ignored "-Wunused-parameter" +#endif + +#include "nrf_soc.h" +#include "nrf_sdm.h" + +/* + * Return to our predefined compiler settings. + */ +#if !defined(__arm) +#pragma GCC diagnostic pop +#endif + +static char friendly_name[MICROBIT_NAME_LENGTH+1]; +static const uint8_t panicFace[5] = {0x1B, 0x1B,0x0,0x0E,0x11}; +static int panic_timeout = 0; +static uint32_t random_value = 0; + +/** + * Determines if a BLE stack is currently running. + * + * @return true is a bluetooth stack is operational, false otherwise. + */ +bool ble_running() +{ + uint8_t t; + sd_softdevice_is_enabled(&t); + return t==1; +} + +/** + * Derived a unique, consistent serial number of this device from internal data. + * + * @return the serial number of this device. + */ +uint32_t microbit_serial_number() +{ + return NRF_FICR->DEVICEID[1]; +} + +/** + * Derive the friendly name for this device, based on its serial number. + * + * @return the serial number of this device. + */ +char* microbit_friendly_name() +{ + const uint8_t codebook[MICROBIT_NAME_LENGTH][MICROBIT_NAME_CODE_LETTERS] = + { + {'z', 'v', 'g', 'p', 't'}, + {'u', 'o', 'i', 'e', 'a'}, + {'z', 'v', 'g', 'p', 't'}, + {'u', 'o', 'i', 'e', 'a'}, + {'z', 'v', 'g', 'p', 't'} + }; + + // We count right to left, so create a pointer to the end of the buffer. + char *name = friendly_name; + name += MICROBIT_NAME_LENGTH; + + // Terminate the string. + *name = 0; + + // Derive our name from the nrf51822's unique ID. + uint32_t n = microbit_serial_number(); + int ld = 1; + int d = MICROBIT_NAME_CODE_LETTERS; + int h; + + for (int i=0; i<MICROBIT_NAME_LENGTH; i++) + { + h = (n % d) / ld; + n -= h; + d *= MICROBIT_NAME_CODE_LETTERS; + ld *= MICROBIT_NAME_CODE_LETTERS; + *--name = codebook[i][h]; + } + + return friendly_name; +} + +/** + * Perform a hard reset of the micro:bit. + */ +void +microbit_reset() +{ + NVIC_SystemReset(); +} + +/** + * Determine the version of microbit-dal currently running. + * @return a pointer to a character buffer containing a representation of the semantic version number. + */ +const char * +microbit_dal_version() +{ + return MICROBIT_DAL_VERSION; +} + +/** + * Defines the length of time that the device will remain in a error state before resetting. + * + * @param iteration The number of times the error code will be displayed before resetting. Set to zero to remain in error state forever. + * + * @code + * microbit_panic_timeout(4); + * @endcode + */ +void microbit_panic_timeout(int iterations) +{ + panic_timeout = iterations; +} + +/** + * Disables all interrupts and user processing. + * Displays "=(" and an accompanying status code on the default display. + * @param statusCode the appropriate status code - 0 means no code will be displayed. Status codes must be in the range 0-255. + * + * @code + * microbit_panic(20); + * @endcode + */ +void microbit_panic(int statusCode) +{ + DigitalIn resetButton(MICROBIT_PIN_BUTTON_RESET); + resetButton.mode(PullUp); + + uint32_t row_mask = 0; + uint32_t col_mask = 0; + uint32_t row_reset = 0x01 << microbitMatrixMap.rowStart; + uint32_t row_data = row_reset; + uint8_t count = panic_timeout ? panic_timeout : 1; + uint8_t strobeRow = 0; + + row_mask = 0; + for (int i = microbitMatrixMap.rowStart; i < microbitMatrixMap.rowStart + microbitMatrixMap.rows; i++) + row_mask |= 0x01 << i; + + for (int i = microbitMatrixMap.columnStart; i < microbitMatrixMap.columnStart + microbitMatrixMap.columns; i++) + col_mask |= 0x01 << i; + + PortOut LEDMatrix(Port0, row_mask | col_mask); + + if(statusCode < 0 || statusCode > 255) + statusCode = 0; + + __disable_irq(); //stop ALL interrupts + + + //point to the font stored in Flash + const unsigned char * fontLocation = MicroBitFont::defaultFont; + + //get individual digits of status code, and place it into a single array/ + const uint8_t* chars[MICROBIT_PANIC_ERROR_CHARS] = { panicFace, fontLocation+((((statusCode/100 % 10)+48)-MICROBIT_FONT_ASCII_START) * 5), fontLocation+((((statusCode/10 % 10)+48)-MICROBIT_FONT_ASCII_START) * 5), fontLocation+((((statusCode % 10)+48)-MICROBIT_FONT_ASCII_START) * 5)}; + + //enter infinite loop. + while(count) + { + //iterate through our chars :) + for(int characterCount = 0; characterCount < MICROBIT_PANIC_ERROR_CHARS; characterCount++) + { + int outerCount = 0; + + //display the current character + while(outerCount < 500) + { + uint32_t col_data = 0; + + int i = 0; + + //if we have hit the row limit - reset both the bit mask and the row variable + if(strobeRow == microbitMatrixMap.rows) + { + strobeRow = 0; + row_data = row_reset; + } + + // Calculate the bitpattern to write. + for (i = 0; i < microbitMatrixMap.columns; i++) + { + int index = (i * microbitMatrixMap.rows) + strobeRow; + + int bitMsk = 0x10 >> microbitMatrixMap.map[index].x; //chars are right aligned but read left to right + int y = microbitMatrixMap.map[index].y; + + if(chars[characterCount][y] & bitMsk) + col_data |= (1 << i); + } + + col_data = ~col_data << microbitMatrixMap.columnStart & col_mask; + + LEDMatrix = col_data | row_data; + + //burn cycles + i = 1000; + while(i>0) + { + // Check if the reset button has been pressed. Interrupts are disabled, so the normal method can't be relied upon... + if (resetButton == 0) + microbit_reset(); + + i--; + } + + //update the bit mask and row count + row_data <<= 1; + strobeRow++; + outerCount++; + } + } + + if (panic_timeout) + count--; + } + + microbit_reset(); +} + +/** + * Generate a random number in the given range. + * We use a simple Galois LFSR random number generator here, + * as a Galois LFSR is sufficient for our applications, and much more lightweight + * than the hardware random number generator built int the processor, which takes + * a long time and uses a lot of energy. + * + * KIDS: You shouldn't use this is the real world to generte cryptographic keys though... + * have a think why not. :-) + * + * @param max the upper range to generate a number for. This number cannot be negative. + * + * @return A random, natural number between 0 and the max-1. Or MICROBIT_INVALID_VALUE if max is <= 0. + * + * @code + * microbit_random(200); //a number between 0 and 199 + * @endcode + */ +int microbit_random(int max) +{ + uint32_t m, result; + + if(max <= 0) + return MICROBIT_INVALID_PARAMETER; + + // Our maximum return value is actually one less than passed + max--; + + do { + m = (uint32_t)max; + result = 0; + do { + // Cycle the LFSR (Linear Feedback Shift Register). + // We use an optimal sequence with a period of 2^32-1, as defined by Bruce Schneier here (a true legend in the field!), + // For those interested, it's documented in his paper: + // "Pseudo-Random Sequence Generator for 32-Bit CPUs: A fast, machine-independent generator for 32-bit Microprocessors" + // https://www.schneier.com/paper-pseudorandom-sequence.html + uint32_t rnd = random_value; + + rnd = ((((rnd >> 31) + ^ (rnd >> 6) + ^ (rnd >> 4) + ^ (rnd >> 2) + ^ (rnd >> 1) + ^ rnd) + & 0x0000001) + << 31 ) + | (rnd >> 1); + + random_value = rnd; + + result = ((result << 1) | (rnd & 0x00000001)); + } while(m >>= 1); + } while (result > (uint32_t)max); + + return result; +} + +/** + * Seed the random number generator (RNG). + * + * This function uses the NRF51822's in built cryptographic random number generator to seed a Galois LFSR. + * We do this as the hardware RNG is relatively high power, and is locked out by the BLE stack internally, + * with a less than optimal application interface. A Galois LFSR is sufficient for our + * applications, and much more lightweight. + */ +void microbit_seed_random() +{ + random_value = 0; + + if(ble_running()) + { + // If Bluetooth is enabled, we need to go through the Nordic software to safely do this. + uint32_t result = sd_rand_application_vector_get((uint8_t*)&random_value, sizeof(random_value)); + + // If we couldn't get the random bytes then at least make the seed non-zero. + if (result != NRF_SUCCESS) + random_value = 0xBBC5EED; + } + else + { + // Othwerwise we can access the hardware RNG directly. + + // Start the Random number generator. No need to leave it running... I hope. :-) + NRF_RNG->TASKS_START = 1; + + for(int i = 0; i < 4; i++) + { + // Clear the VALRDY EVENT + NRF_RNG->EVENTS_VALRDY = 0; + + // Wait for a number ot be generated. + while(NRF_RNG->EVENTS_VALRDY == 0); + + random_value = (random_value << 8) | ((int) NRF_RNG->VALUE); + } + + // Disable the generator to save power. + NRF_RNG->TASKS_STOP = 1; + } +} + +/** + * Seed the pseudo random number generator (RNG) using the given 32-bit value. + * This function does not use the NRF51822's in built cryptographic random number generator. + * + * @param seed The value to use as a seed. + */ +void microbit_seed_random(uint32_t seed) +{ + random_value = seed; +}