From 9f28e53c71d28d04e2775c59944d2887a99f1e86 Mon Sep 17 00:00:00 2001 From: Josh Rahm Date: Sun, 22 Nov 2020 01:06:30 -0700 Subject: Large reorganization. What was in core/ is now moved to arch/stm34l4xxx/peripherals. This new directory is *supposed to* to contain raw header files defining just the pertinent register structures for the various peripherals. Peripheral management belongs somewhere in the new `kern/..` directories. This is not completely the case at the moment, so more refactoring needs to be done. What was sitting in the root has now been moved into the kern/ directory. The kern/ directory is to contain everything else other than raw device register definitions. The root of the kern/ tree is reserved for standard library-esque headers. The kern/ directory contains management systems for that peripheral. (At the moment DMA is the only peripheral with a decent management system.) Preferably these peripheral systems should only include their correlating header in arch/stm34l4xxx/peripherals, and use other management systems for handling other peripherals rather than manipulating their raw registers directly. (Though this ideal will require much more critical mass of management systems.) --- 02-usart/src/kern/spin.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) create mode 100644 02-usart/src/kern/spin.c (limited to '02-usart/src/kern/spin.c') diff --git a/02-usart/src/kern/spin.c b/02-usart/src/kern/spin.c new file mode 100644 index 0000000..7c4f6eb --- /dev/null +++ b/02-usart/src/kern/spin.c @@ -0,0 +1,49 @@ +#include "kern/spin.h" +#include "kern/delay.h" +#include "arch/stm32l4xxx/peripherals/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