From 7aa10db46c13ad8adc88aadff39b8cf6b15db09d Mon Sep 17 00:00:00 2001 From: Josh Rahm Date: Tue, 23 Jan 2018 23:14:31 -0700 Subject: rename folders to give notion of progression --- 01-system-clock/src/spin.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) create mode 100644 01-system-clock/src/spin.c (limited to '01-system-clock/src/spin.c') diff --git a/01-system-clock/src/spin.c b/01-system-clock/src/spin.c new file mode 100644 index 0000000..fbd16b6 --- /dev/null +++ b/01-system-clock/src/spin.c @@ -0,0 +1,49 @@ +#include "spin.h" +#include "delay.h" +#include "gpio.h" + +#define SHORT_DELAY 200000 +#define LONG_DELAY (SHORT_DELAY * 2) + +static void flash_bit( + uint32_t base, gpio_output_pin_t out_pin, + uint8_t bit /* 0 => 0, non-zero => 1 */) +{ + pin_on(out_pin); + if (bit) { + delay(base * 2); + } else { + delay(base); + } + pin_off(out_pin); + delay(base); +} + +void spin(uint32_t base, uint8_t c) +{ + uint8_t code; + __IO gpio_port_t* port_b = enable_gpio(GPIO_PORT_B); + gpio_output_pin_t pin3 = set_gpio_pin_output(port_b, PIN_3); + + for (;;) { + code = c; + flash_bit(base, pin3, code & 0x80); + code <<= 1; + flash_bit(base, pin3, code & 0x80); + code <<= 1; + flash_bit(base, pin3, code & 0x80); + code <<= 1; + flash_bit(base, pin3, code & 0x80); + + code <<= 1; + flash_bit(base, pin3, code & 0x80); + code <<= 1; + flash_bit(base, pin3, code & 0x80); + code <<= 1; + flash_bit(base, pin3, code & 0x80); + code <<= 1; + flash_bit(base, pin3, code & 0x80); + + delay(base * 4); + } +} -- cgit