Add example for nucleo-h563zi

examples/stm32/nucleo-h563zi-make-baremetal-builtin/Makefile

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+CFLAGS  = -W -Wall -Wextra -Werror -Wundef -Wshadow -Wdouble-promotion
+CFLAGS += -Wformat-truncation -fno-common -Wconversion -Wno-sign-conversion
+CFLAGS += -g3 -Os -ffunction-sections -fdata-sections
+CFLAGS += -I. -Icmsis_core/CMSIS/Core/Include -Icmsis_h5/Include
+CFLAGS += -mcpu=cortex-m33 -mthumb -mfpu=fpv5-sp-d16 -mfloat-abi=hard
+LDFLAGS ?= -Tlink.ld -nostdlib -nostartfiles --specs nano.specs -lc -lgcc -Wl,--gc-sections -Wl,-Map=$@.map
+
+SOURCES = main.c syscalls.c sysinit.c
+SOURCES += cmsis_h5/Source/Templates/gcc/startup_stm32h563xx.s # ST startup file. Compiler-dependent!
+
+# Mongoose-specific. See https://mongoose.ws/documentation/#build-options
+SOURCES += mongoose.c net.c packed_fs.c
+CFLAGS += -DMG_ENABLE_TCPIP=1 -DMG_ARCH=MG_ARCH_NEWLIB -DMG_ENABLE_CUSTOM_MILLIS=1
+CFLAGS += -DMG_ENABLE_CUSTOM_RANDOM=1 -DMG_ENABLE_PACKED_FS=1 
+CFLAGS += -DMG_ENABLE_DRIVER_STM32H=1 $(CFLAGS_EXTRA)
+CFLAGS += $(CFLAGS_EXTRA)
+
+# Example specific build options. See README.md
+CFLAGS += -DHTTP_URL=\"http://0.0.0.0/\" -DHTTPS_URL=\"https://0.0.0.0/\"
+
+ifeq ($(OS),Windows_NT)
+  RM = cmd /C del /Q /F /S
+else
+  RM = rm -rf
+endif
+
+all build example: firmware.bin
+
+firmware.bin: firmware.elf
+	arm-none-eabi-objcopy -O binary $< $@
+	ls -l firmware.*
+
+firmware.elf: cmsis_core cmsis_h5 $(SOURCES) hal.h link.ld Makefile
+	arm-none-eabi-gcc $(SOURCES) $(CFLAGS) $(LDFLAGS) -o $@
+
+flash: firmware.bin
+	st-flash --debug --freq=200 --reset write $< 0x8000000
+
+cmsis_core:     # ARM CMSIS core headers
+	git clone --depth 1 -b 5.9.0 https://github.com/ARM-software/CMSIS_5 $@
+cmsis_h5:       # ST CMSIS headers for STM32H5 series
+	git clone --depth 1 -b main https://github.com/STMicroelectronics/cmsis_device_h5 $@
+mbedtls:        # mbedTLS library
+	git clone --depth 1 -b v2.28.2 https://github.com/mbed-tls/mbedtls $@
+
+ifeq ($(TLS), mbedtls)
+CFLAGS += -DMG_TLS=MG_TLS_MBED -Wno-conversion -Imbedtls/include
+CFLAGS += -DMBEDTLS_CONFIG_FILE=\"mbedtls_config.h\" mbedtls/library/*.c
+firmware.elf: mbedtls
+endif
+
+# Automated remote test. Requires env variable VCON_API_KEY set. See https://vcon.io/automated-firmware-tests/
+DEVICE_URL ?= https://dash.vcon.io/api/v3/devices/10
+update: firmware.bin
+	curl --fail-with-body -su :$(VCON_API_KEY) $(DEVICE_URL)/ota --data-binary @$<
+
+test update: CFLAGS += -DUART_DEBUG=USART1
+test: update
+	curl --fail-with-body -su :$(VCON_API_KEY) $(DEVICE_URL)/tx?t=5 | tee /tmp/output.txt
+	grep 'READY, IP:' /tmp/output.txt       # Check for network init
+
+clean:
+	$(RM) firmware.* *.su cmsis_core cmsis_h5 mbedtls

examples/stm32/nucleo-h563zi-make-baremetal-builtin/README.md

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+# Baremetal web device dashboard on NUCLEO-H563ZI
+
+See https://mongoose.ws/tutorials/stm32/all-make-baremetal-builtin/

examples/stm32/nucleo-h563zi-make-baremetal-builtin/hal.h

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+// Copyright (c) 2022-2023 Cesanta Software Limited
+// All rights reserved
+//
+// Datasheet: RM0481, devboard manual: UM3115
+// https://www.st.com/resource/en/reference_manual/rm0481-stm32h563h573-and-stm32h562-armbased-32bit-mcus-stmicroelectronics.pdf
+// Alternate functions: https://www.st.com/resource/en/datasheet/stm32h563vi.pdf
+
+#pragma once
+
+#include <stm32h563xx.h>
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define BIT(x) (1UL << (x))
+#define SETBITS(R, CLEARMASK, SETMASK) (R) = ((R) & ~(CLEARMASK)) | (SETMASK)
+#define PIN(bank, num) ((((bank) - 'A') << 8) | (num))
+#define PINNO(pin) (pin & 255)
+#define PINBANK(pin) (pin >> 8)
+
+#define LED1 PIN('B', 0)  // On-board LED pin (green)
+#define LED2 PIN('F', 4)  // On-board LED pin (yellow)
+#define LED3 PIN('G', 4)  // On-board LED pin (red)
+
+#define LED LED2  // Use yellow LED for blinking
+
+// TODO(cpq): Using HSI clock, 64Mhz. Switch to PLL clock and maximum frequency
+#define CPU_FREQUENCY 64000000
+#define APB2_FREQUENCY CPU_FREQUENCY
+#define APB1_FREQUENCY CPU_FREQUENCY
+
+static inline void spin(volatile uint32_t n) {
+  while (n--) (void) 0;
+}
+
+enum { GPIO_MODE_INPUT, GPIO_MODE_OUTPUT, GPIO_MODE_AF, GPIO_MODE_ANALOG };
+enum { GPIO_OTYPE_PUSH_PULL, GPIO_OTYPE_OPEN_DRAIN };
+enum { GPIO_SPEED_LOW, GPIO_SPEED_MEDIUM, GPIO_SPEED_HIGH, GPIO_SPEED_INSANE };
+enum { GPIO_PULL_NONE, GPIO_PULL_UP, GPIO_PULL_DOWN };
+
+#define GPIO(N) ((GPIO_TypeDef *) ((GPIOA_BASE_NS) + 0x400 * (N)))
+
+static GPIO_TypeDef *gpio_bank(uint16_t pin) {
+  return GPIO(PINBANK(pin));
+}
+static inline void gpio_toggle(uint16_t pin) {
+  GPIO_TypeDef *gpio = gpio_bank(pin);
+  uint32_t mask = BIT(PINNO(pin));
+  gpio->BSRR = mask << (gpio->ODR & mask ? 16 : 0);
+}
+static inline int gpio_read(uint16_t pin) {
+  return gpio_bank(pin)->IDR & BIT(PINNO(pin)) ? 1 : 0;
+}
+static inline void gpio_write(uint16_t pin, bool val) {
+  GPIO_TypeDef *gpio = gpio_bank(pin);
+  gpio->BSRR = BIT(PINNO(pin)) << (val ? 0 : 16);
+}
+static inline void gpio_init(uint16_t pin, uint8_t mode, uint8_t type,
+                             uint8_t speed, uint8_t pull, uint8_t af) {
+  GPIO_TypeDef *gpio = gpio_bank(pin);
+  uint8_t n = (uint8_t) (PINNO(pin));
+  RCC->AHB2ENR |= BIT(PINBANK(pin));  // Enable GPIO clock
+  SETBITS(gpio->OTYPER, 1UL << n, ((uint32_t) type) << n);
+  SETBITS(gpio->OSPEEDR, 3UL << (n * 2), ((uint32_t) speed) << (n * 2));
+  SETBITS(gpio->PUPDR, 3UL << (n * 2), ((uint32_t) pull) << (n * 2));
+  SETBITS(gpio->AFR[n >> 3], 15UL << ((n & 7) * 4),
+          ((uint32_t) af) << ((n & 7) * 4));
+  SETBITS(gpio->MODER, 3UL << (n * 2), ((uint32_t) mode) << (n * 2));
+}
+static inline void gpio_input(uint16_t pin) {
+  gpio_init(pin, GPIO_MODE_INPUT, GPIO_OTYPE_PUSH_PULL, GPIO_SPEED_HIGH,
+            GPIO_PULL_NONE, 0);
+}
+static inline void gpio_output(uint16_t pin) {
+  gpio_init(pin, GPIO_MODE_OUTPUT, GPIO_OTYPE_PUSH_PULL, GPIO_SPEED_HIGH,
+            GPIO_PULL_NONE, 0);
+}
+
+#ifndef UART_DEBUG
+#define UART_DEBUG USART3
+#endif
+
+static inline bool uart_init(USART_TypeDef *uart, unsigned long baud) {
+  uint8_t af = 7;           // Alternate function
+  uint16_t rx = 0, tx = 0;  // pins
+  uint32_t freq = 0;        // Bus frequency. UART1 is on APB2, rest on APB1
+
+  if (uart == USART1) {
+    freq = APB2_FREQUENCY, RCC->APB2ENR |= RCC_APB2ENR_USART1EN;
+    tx = PIN('A', 9), rx = PIN('A', 10);
+  } else if (uart == USART2) {
+    freq = APB1_FREQUENCY, RCC->APB1LENR |= RCC_APB1LENR_USART2EN;
+    tx = PIN('A', 2), rx = PIN('A', 3);
+  } else if (uart == USART3) {
+    freq = APB1_FREQUENCY, RCC->APB1LENR |= RCC_APB1LENR_USART3EN;
+    tx = PIN('D', 8), rx = PIN('D', 9);
+  } else {
+    return false;
+  }
+  gpio_init(tx, GPIO_MODE_AF, GPIO_OTYPE_PUSH_PULL, GPIO_SPEED_HIGH, 0, af);
+  gpio_init(rx, GPIO_MODE_AF, GPIO_OTYPE_PUSH_PULL, GPIO_SPEED_HIGH, 0, af);
+  uart->CR1 = 0;                            // Disable UART
+  uart->BRR = freq / baud;                  // Set baud rate
+  uart->CR1 = USART_CR1_RE | USART_CR1_TE;  // Set mode to TX & RX
+  uart->CR1 |= USART_CR1_UE;                // Enable UART
+  return true;
+}
+static inline void uart_write_byte(USART_TypeDef *uart, uint8_t byte) {
+  uart->TDR = byte;
+  while ((uart->ISR & BIT(7)) == 0) spin(1);
+}
+static inline void uart_write_buf(USART_TypeDef *uart, char *buf, size_t len) {
+  while (len-- > 0) uart_write_byte(uart, *(uint8_t *) buf++);
+}
+static inline int uart_read_ready(USART_TypeDef *uart) {
+  return uart->ISR & BIT(5);  // If RXNE bit is set, data is ready
+}
+static inline uint8_t uart_read_byte(USART_TypeDef *uart) {
+  return (uint8_t) (uart->RDR & 255);
+}
+
+static inline void rng_init(void) {
+  RCC->AHB2ENR |= RCC_AHB2ENR_RNGEN;  // Enable RNG clock
+  RNG->CR |= RNG_CR_RNGEN;            // Enable RNG
+}
+static inline uint32_t rng_read(void) {
+  // while ((RNG->SR & RNG_SR_DRDY) == 0) spin(1);
+  // return RNG->DR;
+  return rand();
+}
+
+static inline void ethernet_init(void) {
+  // Initialise Ethernet. Enable MAC GPIO pins, see UM3115 section 10.7
+  uint16_t pins[] = {PIN('A', 1),  PIN('A', 2),  PIN('A', 7),
+                     PIN('B', 15), PIN('C', 1),  PIN('C', 4),
+                     PIN('C', 5),  PIN('G', 11), PIN('G', 13)};
+  for (size_t i = 0; i < sizeof(pins) / sizeof(pins[0]); i++) {
+    gpio_init(pins[i], GPIO_MODE_AF, GPIO_OTYPE_PUSH_PULL, GPIO_SPEED_INSANE,
+              GPIO_PULL_NONE, 11);  // 11 is the Ethernet function
+  }
+  NVIC_EnableIRQ(ETH_IRQn);           // Setup Ethernet IRQ handler
+  RCC->APB3ENR |= RCC_APB3ENR_SBSEN;  // Enable SBS clock
+  SETBITS(SBS->PMCR, SBS_PMCR_ETH_SEL_PHY, SBS_PMCR_ETH_SEL_PHY_2);  // RMII
+  RCC->AHB1ENR |= RCC_AHB1ENR_ETHEN | RCC_AHB1ENR_ETHRXEN | RCC_AHB1ENR_ETHTXEN;
+}
+
+#define UUID ((uint32_t *) UID_BASE)  // Unique 96-bit chip ID
+
+// Helper macro for MAC generation
+#define GENERATE_LOCALLY_ADMINISTERED_MAC()                         \
+  {                                                                 \
+    2, UUID[0] & 255, (UUID[0] >> 10) & 255, (UUID[0] >> 19) & 255, \
+        UUID[1] & 255, UUID[2] & 255                                \
+  }

examples/stm32/nucleo-h563zi-make-baremetal-builtin/link.ld

@@ -0,0 +1,29 @@
+ENTRY(Reset_Handler);
+MEMORY {
+  flash(rx) : ORIGIN = 0x08000000, LENGTH = 2048k
+  sram(rwx) : ORIGIN = 0x20000000, LENGTH = 640k 
+}
+_estack     = ORIGIN(sram) + LENGTH(sram);    /* stack points to end of SRAM */
+
+SECTIONS {
+  .vectors  : { KEEP(*(.isr_vector)) }  > flash
+  .text     : { *(.text* .text.*) }     > flash
+  .rodata   : { *(.rodata*) }           > flash
+
+  .data : {
+    _sdata = .;   /* for init_ram() */
+    *(.first_data)
+    *(.data SORT(.data.*))
+    _edata = .;  /* for init_ram() */
+  } > sram AT > flash
+  _sidata = LOADADDR(.data);
+
+  .bss : {
+    _sbss = .;              /* for init_ram() */
+    *(.bss SORT(.bss.*) COMMON)
+    _ebss = .;              /* for init_ram() */
+  } > sram
+
+  . = ALIGN(8);
+  _end = .;     /* for cmsis_gcc.h and init_ram() */
+}

examples/stm32/nucleo-h563zi-make-baremetal-builtin/main.c

@@ -0,0 +1,67 @@
+// Copyright (c) 2023 Cesanta Software Limited
+// All rights reserved
+
+#include "hal.h"
+#include "mongoose.h"
+#include "net.h"
+
+#define BLINK_PERIOD_MS 1000  // LED blinking period in millis
+
+static volatile uint64_t s_ticks;  // Milliseconds since boot
+void SysTick_Handler(void) {       // SyStick IRQ handler, triggered every 1ms
+  s_ticks++;
+}
+
+uint64_t mg_millis(void) {  // Let Mongoose use our uptime function
+  return s_ticks;           // Return number of milliseconds since boot
+}
+
+void mg_random(void *buf, size_t len) {  // Use on-board RNG
+  for (size_t n = 0; n < len; n += sizeof(uint32_t)) {
+    uint32_t r = rng_read();
+    memcpy((char *) buf + n, &r, n + sizeof(r) > len ? len - n : sizeof(r));
+  }
+}
+
+void timer_fn(void *arg) {
+  gpio_toggle(LED);                                      // Blink LED
+  struct mg_tcpip_if *ifp = arg;                         // And show
+  const char *names[] = {"down", "up", "req", "ready"};  // network stats
+  MG_INFO(("Ethernet: %s, IP: %M, rx:%u, tx:%u, dr:%u, er:%u",
+           names[ifp->state], mg_print_ip4, &ifp->ip, ifp->nrecv, ifp->nsent,
+           ifp->ndrop, ifp->nerr));
+}
+
+int main(void) {
+  gpio_output(LED);               // Setup green LED
+  uart_init(UART_DEBUG, 115200);  // Initialise debug printf
+  ethernet_init();                // Initialise ethernet pins
+
+  MG_INFO(("Starting, CPU freq %g MHz", (double) SystemCoreClock / 1000000));
+  struct mg_mgr mgr;        // Initialise
+  mg_mgr_init(&mgr);        // Mongoose event manager
+  mg_log_set(MG_LL_DEBUG);  // Set log level
+
+  // Initialise Mongoose network stack
+  struct mg_tcpip_driver_stm32h_data driver_data = {.mdc_cr = 0};
+  struct mg_tcpip_if mif = {.mac = GENERATE_LOCALLY_ADMINISTERED_MAC(),
+                            // Uncomment below for static configuration:
+                            // .ip = mg_htonl(MG_U32(192, 168, 0, 223)),
+                            // .mask = mg_htonl(MG_U32(255, 255, 255, 0)),
+                            // .gw = mg_htonl(MG_U32(192, 168, 0, 1)),
+                            .driver = &mg_tcpip_driver_stm32h,
+                            .driver_data = &driver_data};
+  mg_tcpip_init(&mgr, &mif);
+  MG_INFO(("MAC: %M. Waiting for IP...", mg_print_mac, mif.mac));
+  while (mif.state != MG_TCPIP_STATE_READY) {
+    mg_mgr_poll(&mgr, 0);
+  }
+  mg_timer_add(&mgr, BLINK_PERIOD_MS, MG_TIMER_REPEAT, timer_fn, &mif);
+  MG_INFO(("Initialising application..."));
+  web_init(&mgr);
+  MG_INFO(("Starting event loop"));
+  for (;;) {
+    mg_mgr_poll(&mgr, 0);
+  }
+  return 0;
+}

examples/stm32/nucleo-h563zi-make-baremetal-builtin/mbedtls_config.h

@@ -0,0 +1,53 @@
+/* Workaround for some mbedtls source files using INT_MAX without including limits.h */
+#include <limits.h>
+
+#define MBEDTLS_NO_PLATFORM_ENTROPY
+#define MBEDTLS_ENTROPY_HARDWARE_ALT
+#define MBEDTLS_SSL_OUT_CONTENT_LEN    2048
+#define MBEDTLS_ALLOW_PRIVATE_ACCESS
+#define MBEDTLS_HAVE_TIME
+#define MBEDTLS_SSL_SESSION_TICKETS
+
+#define MBEDTLS_CIPHER_MODE_CBC
+#define MBEDTLS_ECP_DP_SECP256R1_ENABLED
+#define MBEDTLS_KEY_EXCHANGE_RSA_ENABLED
+#define MBEDTLS_PKCS1_V15
+#define MBEDTLS_SHA256_SMALLER
+#define MBEDTLS_SSL_SERVER_NAME_INDICATION
+#define MBEDTLS_AES_C
+#define MBEDTLS_ASN1_PARSE_C
+#define MBEDTLS_BIGNUM_C
+#define MBEDTLS_CIPHER_C
+#define MBEDTLS_CTR_DRBG_C
+#define MBEDTLS_ENTROPY_C
+#define MBEDTLS_ERROR_C
+#define MBEDTLS_MD_C
+#define MBEDTLS_MD5_C
+#define MBEDTLS_OID_C
+#define MBEDTLS_PKCS5_C
+#define MBEDTLS_PK_C
+#define MBEDTLS_PK_PARSE_C
+#define MBEDTLS_PLATFORM_C
+#define MBEDTLS_RSA_C
+#define MBEDTLS_SHA1_C
+#define MBEDTLS_SHA224_C
+#define MBEDTLS_SHA256_C
+#define MBEDTLS_SHA512_C
+#define MBEDTLS_SSL_CLI_C
+#define MBEDTLS_SSL_SRV_C
+#define MBEDTLS_SSL_TLS_C
+#define MBEDTLS_X509_CRT_PARSE_C
+#define MBEDTLS_X509_USE_C
+#define MBEDTLS_AES_FEWER_TABLES
+#define MBEDTLS_PEM_PARSE_C
+#define MBEDTLS_BASE64_C
+#define MBEDTLS_SSL_TICKET_C
+
+#define MBEDTLS_SSL_PROTO_TLS1_2
+#define MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED
+#define MBEDTLS_GCM_C
+#define MBEDTLS_ECDH_C
+#define MBEDTLS_ECP_C
+#define MBEDTLS_ECDSA_C
+#define MBEDTLS_ASN1_WRITE_C
+

examples/stm32/nucleo-h563zi-make-baremetal-builtin/mongoose.c

@@ -0,0 +1 @@
+../../../mongoose.c

examples/stm32/nucleo-h563zi-make-baremetal-builtin/mongoose.h

@@ -0,0 +1 @@
+../../../mongoose.h

examples/stm32/nucleo-h563zi-make-baremetal-builtin/net.c

@@ -0,0 +1 @@
+../../device-dashboard/net.c

examples/stm32/nucleo-h563zi-make-baremetal-builtin/net.h

@@ -0,0 +1 @@
+../../device-dashboard/net.h

examples/stm32/nucleo-h563zi-make-baremetal-builtin/packed_fs.c

@@ -0,0 +1 @@
+../../device-dashboard/packed_fs.c

examples/stm32/nucleo-h563zi-make-baremetal-builtin/syscalls.c

@@ -0,0 +1,98 @@
+#include <sys/stat.h>
+
+#include "hal.h"
+
+int _fstat(int fd, struct stat *st) {
+  if (fd < 0) return -1;
+  st->st_mode = S_IFCHR;
+  return 0;
+}
+
+void *_sbrk(int incr) {
+  extern char _end;
+  static unsigned char *heap = NULL;
+  unsigned char *prev_heap;
+  unsigned char x = 0, *heap_end = (unsigned char *)((size_t) &x - 512);
+  (void) x;
+  if (heap == NULL) heap = (unsigned char *) &_end;
+  prev_heap = heap;
+  if (heap + incr > heap_end) return (void *) -1;
+  heap += incr;
+  return prev_heap;
+}
+
+int _open(const char *path) {
+  (void) path;
+  return -1;
+}
+
+int _close(int fd) {
+  (void) fd;
+  return -1;
+}
+
+int _isatty(int fd) {
+  (void) fd;
+  return 1;
+}
+
+int _lseek(int fd, int ptr, int dir) {
+  (void) fd, (void) ptr, (void) dir;
+  return 0;
+}
+
+void _exit(int status) {
+  (void) status;
+  for (;;) asm volatile("BKPT #0");
+}
+
+void _kill(int pid, int sig) {
+  (void) pid, (void) sig;
+}
+
+int _getpid(void) {
+  return -1;
+}
+
+int _write(int fd, char *ptr, int len) {
+  (void) fd, (void) ptr, (void) len;
+  if (fd == 1) uart_write_buf(UART_DEBUG, ptr, (size_t) len);
+  return -1;
+}
+
+int _read(int fd, char *ptr, int len) {
+  (void) fd, (void) ptr, (void) len;
+  return -1;
+}
+
+int _link(const char *a, const char *b) {
+  (void) a, (void) b;
+  return -1;
+}
+
+int _unlink(const char *a) {
+  (void) a;
+  return -1;
+}
+
+int _stat(const char *path, struct stat *st) {
+  (void) path, (void) st;
+  return -1;
+}
+
+int mkdir(const char *path, mode_t mode) {
+  (void) path, (void) mode;
+  return -1;
+}
+
+void _init(void) {}
+
+extern uint64_t mg_now(void);
+
+int _gettimeofday(struct timeval *tv, void *tz) {
+  uint64_t now = mg_now();
+  (void) tz;
+  tv->tv_sec = (time_t) (now / 1000);
+  tv->tv_usec = (unsigned long) ((now % 1000) * 1000);
+  return 0;
+}

examples/stm32/nucleo-h563zi-make-baremetal-builtin/sysinit.c

@@ -0,0 +1,18 @@
+// Copyright (c) 2023 Cesanta Software Limited
+// All rights reserved
+//
+// This file contains essentials required by the CMSIS:
+// uint32_t SystemCoreClock - holds the system core clock value
+// SystemInit() - initialises the system, e.g. sets up clocks
+
+#include "hal.h"
+
+uint32_t SystemCoreClock = CPU_FREQUENCY;
+
+void SystemInit(void) {  // Called automatically by startup code
+  SCB->CPACR |= ((3UL << 20U) | (3UL << 22U));  // Enable FPU
+  RCC->CR = RCC_CR_HSION;  // Clear HSI clock divisor. SYS clock 64Mhz
+  while ((RCC->CR & RCC_CR_HSIRDY) == 0) spin(1);  // Wait until done
+  rng_init();                            // Initialise random number generator
+  SysTick_Config(CPU_FREQUENCY / 1000);  // Sys tick every 1ms
+}