*(volatile uint32_t *)0x60000304 = 1 << 13; // write HIGH to GPIO13
*(volatile uint32_t *)0x60000308 = 1 << 13; // write LOW to GPIO13
*(volatile uint32_t *)0x60000304 = 1 << 13; // write HIGH to GPIO13
*(volatile uint32_t *)0x60000308 = 1 << 13; // write LOW to GPIO13