diff options
Diffstat (limited to '01-system-clock')
| -rw-r--r-- | 01-system-clock/Makefile.preamble | 21 | ||||
| -rw-r--r-- | 01-system-clock/README | 17 | ||||
| -rwxr-xr-x | 01-system-clock/genmake.pl | 70 | ||||
| -rw-r--r-- | 01-system-clock/include/clock.h | 118 | ||||
| -rw-r--r-- | 01-system-clock/include/common.h | 14 | ||||
| -rw-r--r-- | 01-system-clock/include/delay.h | 12 | ||||
| -rw-r--r-- | 01-system-clock/include/flash.h | 20 | ||||
| -rw-r--r-- | 01-system-clock/include/gpio.h | 120 | ||||
| -rw-r--r-- | 01-system-clock/include/isr_vector.h | 20 | ||||
| -rw-r--r-- | 01-system-clock/include/rcc.h | 81 | ||||
| -rw-r--r-- | 01-system-clock/include/spin.h | 15 | ||||
| -rw-r--r-- | 01-system-clock/linker/linker_script.ld | 36 | ||||
| -rw-r--r-- | 01-system-clock/src/clock.c | 106 | ||||
| -rw-r--r-- | 01-system-clock/src/delay.c | 9 | ||||
| -rw-r--r-- | 01-system-clock/src/gpio.c | 37 | ||||
| -rw-r--r-- | 01-system-clock/src/isr_vector.c | 165 | ||||
| -rw-r--r-- | 01-system-clock/src/main.c | 36 | ||||
| -rw-r--r-- | 01-system-clock/src/spin.c | 49 | ||||
| -rw-r--r-- | 01-system-clock/src/vector.c | 0 |
19 files changed, 946 insertions, 0 deletions
diff --git a/01-system-clock/Makefile.preamble b/01-system-clock/Makefile.preamble new file mode 100644 index 0000000..3c8a61b --- /dev/null +++ b/01-system-clock/Makefile.preamble @@ -0,0 +1,21 @@ +OPT?=-O +PREFIX?=arm-unknown-eabi- +CC=$(PREFIX)gcc +LD=$(PREFIX)ld +CFLAGS?=$(OPT) -mcpu=cortex-m4 -mthumb -g -lgcc -static -nostartfiles -Iinclude +LD_FLAGS?=-T linker/linker_script.ld -nostdlib --cref -Map linker/main.map -static + + +all: _$(PREFIX)_obs/main.elf + +_$(PREFIX)_obs/main.bin: _$(PREFIX)_obs/main.elf + $(PREFIX)objcopy -O binary _$(PREFIX)_obs/main.elf _$(PREFIX)_obs/main.bin + +flash: _$(PREFIX)_obs/main.bin + st-flash write _$(PREFIX)_obs/main.bin 0x8000000 + +clean: + rm -rf _*_obs + +genmake: + ./genmake.pl > Makefile diff --git a/01-system-clock/README b/01-system-clock/README new file mode 100644 index 0000000..fb9b5df --- /dev/null +++ b/01-system-clock/README @@ -0,0 +1,17 @@ +This is much more complex than the simple hello script, but most is boiler plate +designed to make future debugging easier. The first addition is a genmake +system where a Makefile may be generated with the command +`./genmake.pl > Makefile` and subsequently with `make genmake`. This will add +build rules for each `c` file. + +There are some added features as well: + +* This code loads values properly from the data and bss segments into memory so + global variables and global constants may be used. + +* This code can properly set the system clock, and does get a full 80MHz out + of it. + +* This code has a `spin()` function that flashes a "morse code" translation + of a binary error code. (1's are dashes, 0's are dots). Gives minimal feedback + until such a time where USART is implemented. diff --git a/01-system-clock/genmake.pl b/01-system-clock/genmake.pl new file mode 100755 index 0000000..341db3d --- /dev/null +++ b/01-system-clock/genmake.pl @@ -0,0 +1,70 @@ +#!/usr/bin/perl + +# This script is designed to introspect C files and generate a makefile to use. + +sub header_deps { + my $file = @_[0]; + my @headers; + + if (open(my $fh, '<:encoding(UTF-8)', $file)) { + print STDERR "\x1b[35m[Trace] - Reading file $file\x1b[00m\n"; + push(@headers, $file); + + while (<$fh>) { + /#include\s+"(.*)"\s*$/ && push(@headers, header_deps("include/$1")); + } + } + + return @headers; +} + +my @files = glob('src/*.c'); +my @obj_files; + +open(my $fh, '<:encoding(UTF-8)', "Makefile.preamble") + or die "Missing Makefile.preamble"; + +while (<$fh>) { + print "$_"; +} + +# Emit a rule that will rerun genmake if the c files do not match. +my $idempotency_cmd = + "ls src/*.c include/*.h| sha1sum | awk '{print \$1}'"; + +my $idempotency_cmd_make = + "ls src/*.c include/*.h | sha1sum | awk '{print \$\$1}'"; + +print "IDEMPOTENCY_HASH=" . `$idempotency_cmd` . "\n"; + +my $arch_obs_dir = "_\$(PREFIX)_obs"; +print "CHEAT_PRE_MAKE := \$(shell mkdir -p $arch_obs_dir)\n"; + +foreach $file (@files) { + my $c_file = $file; + (my $file_no_ext = $file) =~ s/src\/(.*)\.c$/\1/g; + + my $obj_file = "$arch_obs_dir/${file_no_ext}.o"; + my $s_file = "${file_no_ext}.s"; + + push(@obj_files, $obj_file); + my @deps = header_deps($c_file); + + my $deps_as_join = join(" ", @deps); + + # Emit the rule to make the object file. + print "$obj_file: $deps_as_join\n\t"; + print '$(CC) -c ' . $c_file . ' -o ' . $obj_file . ' $(CFLAGS)' . "\n\n"; + + # Emit the rule to make the assembly file. + print "$s_file: $deps_as_join\n\t"; + print '$(CC) -S ' . $c_file . ' -o ' . $s_file . ' $(CFLAGS)' . "\n\n"; +} + +my $obj_files_deps = join(' ', @obj_files); +print "FORCE:\n\t\n\n"; +print "$arch_obs_dir/main.elf: FORCE $obj_files_deps linker/linker_script.ld\n\t"; +print "([ \"\$\$($idempotency_cmd_make)\" != \"\$(IDEMPOTENCY_HASH)\" ] " + . "&& ./genmake.pl > Makefile && make main.elf ) " + . "|| " + . "\$(LD) -o $arch_obs_dir/main.elf \$(LD_FLAGS) $obj_files_deps\n\n"; diff --git a/01-system-clock/include/clock.h b/01-system-clock/include/clock.h new file mode 100644 index 0000000..de4fb96 --- /dev/null +++ b/01-system-clock/include/clock.h @@ -0,0 +1,118 @@ +#ifndef CLOCK_H__ +#define CLOCK_H__ + +#include <stdint.h> +#include "rcc.h" + +#define PERIPH_BASE ((uint32_t)0x40000000) +#define AHBPERIPH_BASE (PERIPH_BASE + 0x00020000) +#define FLASH_R_BASE (AHBPERIPH_BASE + 0x00003C00) +#define PWR_BASE (PERIPH_BASE + 0x7000) +#define PWR_CSR_VOSF ((uint16_t)0x0010) /*!< Voltage Scaling select flag */ + +#ifndef __IO +#define __IO volatile +#endif + +typedef struct { + __IO uint32_t cr; + __IO uint32_t csr; +} pwr_t; + +// typedef struct { +// __IO uint32_t acr; +// __IO uint32_t pecr; +// __IO uint32_t pdkeyr; +// __IO uint32_t pekeyr; +// __IO uint32_t prgkeyr; +// __IO uint32_t optkeyr; +// __IO uint32_t sr; +// __IO uint32_t obr; +// __IO uint32_t wrpr; +// } flash_t; + +// #define FLASH (*(flash_t*) (FLASH_R_BASE)) +#define PWR (*(pwr_t*)(PWR_BASE)) + +/* Valid values for the PLLR/PLLQ bits of the PLLCFG register. */ +typedef enum { + PLL_DIVISOR_2 = 1, + PLL_DIVISOR_4 = 3, + PLL_DIVISOR_6 = 5, + PLL_DIVISOR_8 = 7, + PLL_DIVISOR_OFF = 0, +} pll_divisor_t; + +/* Valid values for the PLLP bits off the PLLCFG register. */ +typedef enum { + PLLP_DIVISOR_7 = 1, + PLLP_DIVISOR_17 = 3, + PLLP_DIVISOR_OFF = 0, +} pllp_divisor_t; + +/* Valid values for the PLLM bits of the PLLCFG register. */ +typedef enum { + PLLM_DIVISOR_1 = 0, + PLLM_DIVISOR_2 = 1, + PLLM_DIVISOR_3 = 2, + PLLM_DIVISOR_4 = 3, + PLLM_DIVISOR_5 = 4, + PLLM_DIVISOR_6 = 5, + PLLM_DIVISOR_7 = 6, + PLLM_DIVISOR_8 = 7, +} pllm_divisor_t; + +/* Possible sources for the input clock. */ +typedef enum { + PLL_SRC_NONE = 0, + PLL_SRC_MSI = 1, + PLL_SRC_HSI = 2, + PLL_SRC_HSE = 3, +} pll_src_t; + +/* Valid sources for the system clock. */ +typedef enum { + SYSTEM_CLOCK_SRC_MSI = 0, + SYSTEM_CLOCK_SRC_HSI = 1, + SYSTEM_CLOCK_SRC_HSE = 2, + SYSTEM_CLOCK_SRC_PLL = 3, +} system_clock_src_t; + +#define E_BADPLLN (-2) +#define E_BADPLLP_DIV (-1) +#define E_TIMEOUT (-3) +#define E_NOT_OFF (-4) +#define E_BAD_ARG (-5) + +/* + * Sets the system clock to a full 80Mhz. + */ +int set_system_clock_MHz(uint8_t mhz); + +/* + * Set the PLL on. + */ +int pll_on(); + +/* + * Set the PLL off. + */ +int pll_off(); + +/* + * Sets the source of the system clock. + */ +int set_system_clock_src(system_clock_src_t src); + +/* + * Configure the PLL. + */ +int configure_pll( + uint8_t pllp_div_factor, pll_divisor_t pllr, /* System clock divisor. */ + pll_divisor_t pllq, /* Divison factor for PLL48M1CLK. */ + pllp_divisor_t pllp, /* Divison factor for PLLSAI2CLK. */ + uint8_t plln, /* PLL numerator. */ + pllm_divisor_t pllm, /* PLL denominator. */ + pll_src_t pllsrc /* PLL source */); + +#endif /* CLOCK_H__ */ diff --git a/01-system-clock/include/common.h b/01-system-clock/include/common.h new file mode 100644 index 0000000..6fc701c --- /dev/null +++ b/01-system-clock/include/common.h @@ -0,0 +1,14 @@ +#ifndef COMMON__H +#define COMMON__H + +/* Define __IO to be volatile if it's not already. */ +#ifndef __IO +#define __IO volatile +#endif + +#define bool int + +#define PACKED __attribute__((packed)) +#define BIT(n) (1 << (n)) + +#endif /* COMMON_H */ diff --git a/01-system-clock/include/delay.h b/01-system-clock/include/delay.h new file mode 100644 index 0000000..65a26d6 --- /dev/null +++ b/01-system-clock/include/delay.h @@ -0,0 +1,12 @@ +#ifndef H__DELAY__ +#define H__DELAY__ + +#include <stdint.h> + +/* + * Loops and count-downs the delay, the time this takes depends on the speed + * of the clock. + */ +void delay(uint32_t delay); + +#endif /* H__DELAY__ */ diff --git a/01-system-clock/include/flash.h b/01-system-clock/include/flash.h new file mode 100644 index 0000000..a163a25 --- /dev/null +++ b/01-system-clock/include/flash.h @@ -0,0 +1,20 @@ +#ifndef H__FLASH_ +#define H__FLASH_ + +#include "common.h" + +/* + * Header file for dealing with flash. + */ + +#define FLASH_BASE 0x40022000 + +typedef struct { + __IO uint32_t ac_r; /* Flash access control register. */ + + /* TODO fill out the rest. */ +} PACKED flash_t; + +#define FLASH (*(__IO flash_t*)FLASH_BASE) + +#endif /* H__FLASH_ */ diff --git a/01-system-clock/include/gpio.h b/01-system-clock/include/gpio.h new file mode 100644 index 0000000..a8f06e2 --- /dev/null +++ b/01-system-clock/include/gpio.h @@ -0,0 +1,120 @@ +#ifndef GPIO_H__ +#define GPIO_H__ + +#include "common.h" + +#include <stdint.h> + +/* + * Possible GPIO ports. + */ +typedef enum { + GPIO_PORT_A = 0, + GPIO_PORT_B = 1, + GPIO_PORT_C = 2, + GPIO_PORT_D = 3 +} gpio_port_number_t; + +/* + * Structure defining the layout of the layout of the GPIO registers on the + * stm32l432 development board. + */ +typedef struct GPIO_PORT_STR { + __IO uint32_t mode_r; /* Mode register */ + __IO uint32_t pupd_r; /* Pull up/pull down/none register */ + __IO uint32_t speed_r; /* Speed register */ + __IO uint32_t type_r; /* Type register */ + __IO uint32_t input_r; /* Input data register */ + __IO uint32_t output_r; /* Output data register */ + __IO uint32_t bsr_r; /* Bit set/reset register */ + __IO uint32_t lock_r; /* Lock register */ + __IO uint32_t altfn_r; /* Alternate function register */ +} PACKED gpio_port_t; + +/* + * Enum defining the PINs in a GPIO port. Each port has 16 pins to use in + * the stm32l432. + */ +typedef enum GPIO_PIN_ENUM { + PIN_0 = 0, + PIN_1 = 1, + PIN_2 = 2, + PIN_3 = 3, + PIN_4 = 4, + PIN_5 = 5, + PIN_6 = 6, + PIN_7 = 7, + PIN_8 = 8, + PIN_9 = 9, + PIN_10 = 10, + PIN_11 = 11, + PIN_12 = 12, + PIN_13 = 13, + PIN_14 = 14, + PIN_15 = 15 +} gpio_pin_t; + +/* + * Enum defining the pin modes that are possible. + */ +typedef enum { + MODE_INPUT = 0, + MODE_OUTPUT = 1, + MODE_ALTERNATE = 2, + MODE_ANALOG = 3 +} gpio_pin_mode_t; + +/* + * Enum defining the pin speeds that are possible. + */ +typedef enum { + SPEED_2MHZ = 0, + SPEED_10MHZ = 1, + SPEED_50MHZ = 3, +} speed_t; + +/* + * Structure defining an OUTPUT pin. Structurally equivalent to the input pin, + * but can be used in a slightly type-safe manner. + */ +typedef struct { + __IO gpio_port_t* gpio_port; + gpio_pin_t pin; +} gpio_output_pin_t; + +/* + * Sets the mode on a GPIO pin. + * + * gpio_port: the gpio port to use. + * pin: the pin number to set. + * pin_mode: the mode to set the pin to. + */ +void set_gpio_pin_mode( + __IO gpio_port_t* gpio_port, gpio_pin_t pin, gpio_pin_mode_t pin_mode); + +/* + * Sets the given GPIO pin to be an output pin. Returns an output_pin struct + * corresponding to + */ +gpio_output_pin_t set_gpio_pin_output( + __IO gpio_port_t* gpio_port, gpio_pin_t pin); + +/* + * Sets an output pin on or off. + * + * pin: the pin to toggle. + * onoff: 0 for off, non-zero of on. + */ +void set_gpio_output_pin(gpio_output_pin_t pin, bool onoff); + +#define pin_on(p) set_gpio_output_pin(p, 1) + +#define pin_off(p) set_gpio_output_pin(p, 0) + +/* + * Enables a GPIO port and returns a reference to the register definition + * of that GPIO port. + */ +__IO gpio_port_t* enable_gpio(gpio_port_number_t number); + +#endif /* GPIO_H__ */ diff --git a/01-system-clock/include/isr_vector.h b/01-system-clock/include/isr_vector.h new file mode 100644 index 0000000..3e55f52 --- /dev/null +++ b/01-system-clock/include/isr_vector.h @@ -0,0 +1,20 @@ +#ifndef h__ISR_VECTOR_H__ +#define h__ISR_VECTOR_H__ + +/* + * Include file for interrupt service routines. + */ + +/* + * The interrupt service routines. These link in the function `main` as the + * main function. + */ +extern const void* isr_vector[]; + +/* + * Defines an error state. This loops forever and defines a distinct flashing + * pattern to let the user know an unhandled ISR happened. + */ +void unhandled_isr(); + +#endif /* h___ISR_VECTOR_H__ */ diff --git a/01-system-clock/include/rcc.h b/01-system-clock/include/rcc.h new file mode 100644 index 0000000..4eeb26b --- /dev/null +++ b/01-system-clock/include/rcc.h @@ -0,0 +1,81 @@ +#ifndef H__RCC_ +#define H__RCC_ + +#include "common.h" + +#define RCC_BASE ((uint32_t)0x40021000) + +typedef struct { + __IO uint32_t c_r; /* Clock control register. 0x00 */ + __IO uint32_t icsc_r; /* Internal clock srcs calibration register. 0x04 */ + __IO uint32_t cfg_r; /* clock confguration register. 0x08 */ + __IO uint32_t pllcfg_r; /* PLL Configuration register. 0x0c */ + __IO uint32_t pllsai1cfg_r; /* PLLSAI1 configuration register. 0x10 */ + + __IO uint32_t reserved_1; /* Not used. offset 0x14. */ + + __IO uint32_t cie_r; /* Clock interrupt enable register. 0x18 */ + __IO uint32_t cif_r; /* Clock interrupt flag regiseter. 0x1c */ + __IO uint32_t cic_r; /* Clock interrupt clear register. 0x20 */ + + __IO uint32_t reserved_2; /* Not used. offset 0x24. */ + + __IO uint32_t ahb1rst_r; /* AHB Peripheral 1 reset register. 0x28 */ + __IO uint32_t ahb2rst_r; /* AHB Peripheral 2 reset register. 0x2c */ + __IO uint32_t ahb3rst_r; /* AHB Peripheral 3 reset register. 0x30 */ + + __IO uint32_t reserved_3; /* Not used. offset 0x34. */ + + __IO uint32_t abp1rst1_r; /* APB Peripheral reset register 1. 0x38 */ + __IO uint32_t abp1rst2_r; /* APB Peripheral reset register 2. 0x3C */ + __IO uint32_t abp2rst_r; /* APB Peripheral reset register. 0x40 */ + + __IO uint32_t reserved_4; /* Not used. offset 0x44. */ + + __IO uint32_t ahb1en_r; /* AHB1 Peripheral enable register. 0x48 */ + __IO uint32_t ahb2en_r; /* AHB2 Peripheral enable register. 0x4C */ + __IO uint32_t ahb3en_r; /* AHB3 Peripheral enable register. 0x50 */ + + __IO uint32_t reserved_5; /* Not used. offset 0x54. */ + + __IO uint32_t apb1en1_r; /* APB1 Peripheral enable register 1. 0x58 */ + __IO uint32_t apb1en2_r; /* APB1 Peripheral enable register 2. 0x5C */ + __IO uint32_t apb2en_r; /* APB2 Peripheral enable register. 0x60 */ + + __IO uint32_t reserved_6; /* Not used. offset 0x64. */ + + /* TODO add the rest starting at offset 0x68. */ + +} PACKED rcc_t; + +#define RCC (*(__IO rcc_t*)RCC_BASE) + +/* Macros to operate on the RCC registers. */ + +/* Sets the HSE. rcc is the RCC to use, e is zero for off, non-zero for on. */ +#define set_hse(rcc, e) \ + do { \ + if (e) { \ + (rcc).c_r |= 1 << 16; \ + } else { \ + (rcc).c_r &= ~(1 << 16); \ + } \ + } while (0) + +/* Sets the HSI. rcc is the RCC to use, e is zero for off, non-zero for on. */ +#define set_hsi(rcc, e) \ + do { \ + if (e) { \ + (rcc).c_r |= 1 << 8; \ + } else { \ + (rcc).c_r &= ~(1 << 8); \ + } \ + } while (0) + +/* Checks to see if the hse is ready. */ +#define hse_ready(rcc) ((rcc).c_r & (1 << 17)) + +/* Checks to see if the hse is ready. */ +#define hsi_ready(rcc) ((rcc).c_r & (1 << 10)) + +#endif diff --git a/01-system-clock/include/spin.h b/01-system-clock/include/spin.h new file mode 100644 index 0000000..a23d25b --- /dev/null +++ b/01-system-clock/include/spin.h @@ -0,0 +1,15 @@ +#ifndef H__SPIN_ +#define H__SPIN_ + +#include <stdint.h> + +/* + * Flash a code on the status LED. + * + * The flash codes a binary from MSB to LSB. A long flash is a 1, a short flash + * is a 0. Each independent flashing is succeced by a break of 4 times that + * of a long flash. + */ +void spin(uint32_t base_delay, uint8_t code); + +#endif /* H__SPIN_ */ diff --git a/01-system-clock/linker/linker_script.ld b/01-system-clock/linker/linker_script.ld new file mode 100644 index 0000000..348d03b --- /dev/null +++ b/01-system-clock/linker/linker_script.ld @@ -0,0 +1,36 @@ +MEMORY +{ + flash : org = 0x08000000, len = 256k + sram1 : org = 0x20000000, len = 48k + sram2 : org = 0x10000000, len = 16k +} + +SECTIONS +{ + /* This is where the code goes. */ + . = ORIGIN(flash); + .text : { + *(.vectors); /* All .vector sections go here. */ + *(.text); /* All .text sections go here. */ + } >flash + + .data : { + /* Data segment as defined in the flash. */ + INIT_DATA_VALUES = LOADADDR(.data); + + /* Data segment where it will be in memory. */ + DATA_SEGMENT_START = .; + *(.data); + DATA_SEGMENT_STOP = .; + + /* Align by 4 so we can optimize the copier to use uint32's. */ + . = ALIGN(0x04); + } >sram1 AT>flash + + BSS_START = .; + .bss : { + *(.bss); + . = ALIGN(0x04); + } > sram1 + BSS_END = .; +} diff --git a/01-system-clock/src/clock.c b/01-system-clock/src/clock.c new file mode 100644 index 0000000..75bac97 --- /dev/null +++ b/01-system-clock/src/clock.c @@ -0,0 +1,106 @@ +/* + * This file sets the system clock to its full glory of 80Mhz + */ + +#include "clock.h" +#include <stdint.h> +#include "flash.h" +#include "gpio.h" +#include "spin.h" + +#define TIMEOUT 10000 + +int pll_off() +{ + uint32_t c; + + RCC.c_r &= ~BIT(24); /* Turn off pll. */ + for (c = 0; c < TIMEOUT && RCC.c_r & BIT(25); ++c) + ; /* Wait for OFF. */ + + if (c == TIMEOUT) { + return E_TIMEOUT; + } + + return 0; +} + +int pll_on() +{ + uint32_t c; + + RCC.c_r |= BIT(24); /* Turn on PLL. */ + for (c = 0; c < TIMEOUT && !(RCC.c_r & BIT(25)); ++c) + ; /* Wait for RDY. */ + + if (c == TIMEOUT) { + return E_TIMEOUT; + } + + return 0; +} + +int configure_pll( + uint8_t pllp_div_factor, pll_divisor_t pllr, /* System clock divisor. */ + pll_divisor_t pllq, /* Divison factor for PLL48M1CLK. */ + pllp_divisor_t pllp, /* Divison factor for PLLSAI2CLK. */ + uint8_t plln, /* PLL numerator. */ + pllm_divisor_t pllm, /* PLL denominator. */ + pll_src_t pllsrc /* PLL source */) +{ + if (RCC.c_r & BIT(25)) { + /* PLL must be off to configure it. */ + return E_NOT_OFF; + } + + /* Make sure inputs are valid. */ + if (pllp_div_factor == 1 || pllp_div_factor > 31) { + return E_BADPLLP_DIV; + } + if (plln < 8 || plln > 86) { + return E_BADPLLN; + } + + RCC.pllcfg_r = (pllp_div_factor << 27) | (pllr << 24) | (pllq << 20) | + (pllp << 16) | (plln << 8) | (pllm << 4) | (pllsrc << 0); + + return 0; +} + +int set_system_clock_MHz(uint8_t mhz) +{ + /* Set the source of the system colck to MSI temporarily. */ + set_system_clock_src(SYSTEM_CLOCK_SRC_MSI); + + if (mhz <= 8 || mhz > 80) { + return E_BAD_ARG; + } + + pll_off(); + + configure_pll( + 0 /* pllp_div_factor */, PLL_DIVISOR_4 /* pllr: VCO / 4 = mhz MHz. */, + PLL_DIVISOR_4 /* pllq: VCO / 4 = mhz MHz */, PLLP_DIVISOR_7 /* pllp */, + + /* The following set the frequency of VCO to (mhz*4)MHz: mhz * 1 * 4MHz. + */ + mhz /* plln | mhz */, PLLM_DIVISOR_1 /* pllm | 01 */, + PLL_SRC_MSI /* pll src | 04 Mhz */); + + pll_on(); + + /* Configure the flash to have 4 wait states. This is required at + * 80 MHz. */ + FLASH.ac_r &= ~0x07; + FLASH.ac_r |= 0x04; + + /* Set the source of the system colck to PLL. */ + set_system_clock_src(SYSTEM_CLOCK_SRC_PLL); + return 0; +} + +int set_system_clock_src(system_clock_src_t src) +{ + uint8_t value = RCC.cfg_r & ~0x03; + RCC.cfg_r = value | src; +} diff --git a/01-system-clock/src/delay.c b/01-system-clock/src/delay.c new file mode 100644 index 0000000..2a16d47 --- /dev/null +++ b/01-system-clock/src/delay.c @@ -0,0 +1,9 @@ +#include "delay.h" + +void delay(uint32_t delay) +{ + while (delay--) { + /* needed to keep the compiler from optimizing away the loop. */ + asm volatile(""); + } +} diff --git a/01-system-clock/src/gpio.c b/01-system-clock/src/gpio.c new file mode 100644 index 0000000..2404398 --- /dev/null +++ b/01-system-clock/src/gpio.c @@ -0,0 +1,37 @@ +#include "gpio.h" +#include "rcc.h" + +/* + * Sets the mode of a pin on a gpio por. + */ +void set_gpio_pin_mode( + __IO gpio_port_t* gpio_port, gpio_pin_t pin, gpio_pin_mode_t mode) +{ + /* Each pin has a 2-bit mode provided at bits pin#*2 and pin#*2+1 */ + gpio_port->mode_r &= ~(0x03 << pin * 2); + gpio_port->mode_r |= mode << pin * 2; +} + +gpio_output_pin_t set_gpio_pin_output( + __IO gpio_port_t* gpio_port, gpio_pin_t pin) +{ + set_gpio_pin_mode(gpio_port, pin, MODE_OUTPUT); + + return (gpio_output_pin_t){.gpio_port = gpio_port, .pin = pin}; +} + +void set_gpio_output_pin(gpio_output_pin_t pin, bool onoff) +{ + if (onoff) { + pin.gpio_port->output_r |= 1 << pin.pin; + } else { + pin.gpio_port->output_r &= ~(1 << pin.pin); + } +} + +#define GPIO_PORTS_BASE_ADDR ((uint32_t)0x48000000) +__IO gpio_port_t* enable_gpio(gpio_port_number_t gpio_port_number) +{ + RCC.ahb2en_r |= 1 << gpio_port_number; /* Enable the GPIO port. */ + return (__IO gpio_port_t*)(GPIO_PORTS_BASE_ADDR + (gpio_port_number * 0x400)); +} diff --git a/01-system-clock/src/isr_vector.c b/01-system-clock/src/isr_vector.c new file mode 100644 index 0000000..674a6bb --- /dev/null +++ b/01-system-clock/src/isr_vector.c @@ -0,0 +1,165 @@ +#include "isr_vector.h" +#include "delay.h" +#include "gpio.h" + +/* Forward-declare the main function. This is implemented in main.c. */ +void main(); + +/* These are defined in the linker script. */ +extern uint32_t INIT_DATA_VALUES; +extern uint32_t DATA_SEGMENT_START; +extern uint32_t DATA_SEGMENT_STOP; +extern uint32_t BSS_START; +extern uint32_t BSS_END; + +/* + * Runs before main. Initializes the data and bss segments by loading them + * into memory. + */ +void init() +{ + uint32_t* src; + uint32_t* dest; + + src = &INIT_DATA_VALUES; + dest = &DATA_SEGMENT_START; + + /* Copy the values from flash into the data segment. */ + while (dest != &DATA_SEGMENT_STOP) { + *(dest++) = *(src++); + } + + /* Everything in the BSS segment is set to zero. */ + dest = &BSS_START; + while (dest != &BSS_END) { + *(dest++) = 0; + } + + /* Jump to main. */ + main(); +} + +const void* vectors[] __attribute__((section(".vectors"))) = { + (void*)0x2000c000, /* Top of stack at top of sram1. 48k */ + init, /* Reset handler */ + unhandled_isr, /* NMI */ + unhandled_isr, /* Hard Fault */ + unhandled_isr, /* MemManage */ + unhandled_isr, /* BusFault */ + unhandled_isr, /* UsageFault */ + unhandled_isr, /* Reserved */ + unhandled_isr, /* Reserved */ + unhandled_isr, /* Reserved */ + unhandled_isr, /* Reserved */ + unhandled_isr, /* SVCall */ + unhandled_isr, /* Debug */ + unhandled_isr, /* Reserved */ + unhandled_isr, /* PendSV */ + unhandled_isr, /* SysTick */ + + /* External interrupt handlers follow */ + unhandled_isr, /* 0 WWDG */ + unhandled_isr, /* 1 PVD */ + unhandled_isr, /* 2 TAMP_SAMP */ + unhandled_isr, /* 3 RTC_WKUP */ + unhandled_isr, /* 4 FLASH */ + unhandled_isr, /* 5 RCC */ + unhandled_isr, /* 6 EXTI0 */ + unhandled_isr, /* 7 EXTI1 */ + unhandled_isr, /* 8 EXTI2 */ + unhandled_isr, /* 9 EXTI3 */ + unhandled_isr, /* 10 EXTI4 */ + unhandled_isr, /* 11 DMA_CH1 */ + unhandled_isr, /* 12 DMA_CH2 */ + unhandled_isr, /* 13 DMA_CH3 */ + unhandled_isr, /* 14 DMA_CH4 */ + unhandled_isr, /* 15 DMA_CH5 */ + unhandled_isr, /* 16 DMA_CH6 */ + unhandled_isr, /* 17 DMA_CH7 */ + unhandled_isr, /* 18 ADC1 */ + unhandled_isr, /* 19 CAN_TX */ + unhandled_isr, /* 20 CAN_RX0 */ + unhandled_isr, /* 21 CAN_RX1 */ + unhandled_isr, /* 22 CAN_SCE */ + unhandled_isr, /* 23 EXTI9_5 */ + unhandled_isr, /* 24 TIM1_BRK/TIM15 */ + unhandled_isr, /* 25 TIM1_UP/TIM16 */ + unhandled_isr, /* 26 TIM1_TRG_COM */ + unhandled_isr, /* 27 TIM1_CC */ + unhandled_isr, /* 28 TIM2 */ + unhandled_isr, /* 29 Reserved */ + unhandled_isr, /* 30 Reserved */ + unhandled_isr, /* 31 I2C1_EV */ + unhandled_isr, /* 32 I2C1_ER */ + unhandled_isr, /* 33 I2C2_EV */ + unhandled_isr, /* 34 I2C2_ER */ + unhandled_isr, /* 35 SPI1 */ + unhandled_isr, /* 36 SPI2 */ + unhandled_isr, /* 37 USART1 */ + unhandled_isr, /* 38 USART2 */ + unhandled_isr, /* 39 USART3 */ + unhandled_isr, /* 40 EXTI15_10 */ + unhandled_isr, /* 41 RTCAlarm */ + unhandled_isr, /* 42 Reserved */ + unhandled_isr, /* 43 Reserved */ + unhandled_isr, /* 44 Reserved */ + unhandled_isr, /* 45 Reserved */ + unhandled_isr, /* 46 Reserved */ + unhandled_isr, /* 47 Reserved */ + unhandled_isr, /* 48 Reserved */ + unhandled_isr, /* 49 SDMMC1 */ + unhandled_isr, /* 50 Reserved */ + unhandled_isr, /* 51 SPI3 */ + unhandled_isr, /* 52 Reserved */ + unhandled_isr, /* 53 Reserved */ + unhandled_isr, /* 54 TIM6_DACUNDER */ + unhandled_isr, /* 55 TIM7 */ + unhandled_isr, /* 56 DMA2_CH1 */ + unhandled_isr, /* 57 DMA2_CH2 */ + unhandled_isr, /* 58 DMA2_CH3 */ + unhandled_isr, /* 59 DMA2_CH4 */ + unhandled_isr, /* 60 DMA2_CH5 */ + unhandled_isr, /* 61 Reserved */ + unhandled_isr, /* 62 Reserved */ + unhandled_isr, /* 63 Reserved*/ + unhandled_isr, /* 64 COMP */ + unhandled_isr, /* 65 LPTIM1 */ + unhandled_isr, /* 66 LPTIM2 */ + unhandled_isr, /* 67 USB_FS */ + unhandled_isr, /* 68 DMA_CH6 */ + unhandled_isr, /* 69 DMA_CH7 */ + unhandled_isr, /* 70 LPUART1 */ + unhandled_isr, /* 71 QUADSPI */ + unhandled_isr, /* 72 I2C3_EV */ + unhandled_isr, /* 73 I2C3_ER */ + unhandled_isr, /* 74 SAI1 */ + unhandled_isr, /* 75 Reserved */ + unhandled_isr, /* 76 SWPMI1 */ + unhandled_isr, /* 77 TSC */ + unhandled_isr, /* 78 Reserved */ + unhandled_isr, /* 79 AES */ + unhandled_isr, /* 80 RNG */ + unhandled_isr, /* 81 FPU */ + unhandled_isr /* 82 CRS */ +}; + +/* + * Does nothing ... forever. + */ +void unhandled_isr() +{ + __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 (;;) { + /* Flash in a distinct pattern to know that something went wrong. */ + + pin_off(pin3); + delay(100000); + pin_on(pin3); + delay(100000); + pin_off(pin3); + delay(100000); + pin_on(pin3); + delay(500000); + } +} diff --git a/01-system-clock/src/main.c b/01-system-clock/src/main.c new file mode 100644 index 0000000..7912bf2 --- /dev/null +++ b/01-system-clock/src/main.c @@ -0,0 +1,36 @@ +#include "clock.h" +#include "delay.h" +#include "gpio.h" +#include "spin.h" + +volatile uint32_t delay_amt = 20000000 / 4; + +/* Main function. This gets executed from the interrupt vector defined above. */ +int main() +{ + /* Enable the GPIO port B. */ + + __IO gpio_port_t* port_b = enable_gpio(GPIO_PORT_B); + gpio_output_pin_t pin3 = set_gpio_pin_output(port_b, PIN_3); + gpio_output_pin_t pin1 = set_gpio_pin_output(port_b, PIN_1); + + /* Enable a higher clock frequency. */ + set_system_clock_MHz(80); + + uint32_t count = 0; + while (1) { + /* Set the GPIO pin to high. */ + pin_off(pin1); + pin_off(pin3); + delay(delay_amt); + + /* Set the GPIO pin to low. */ + if (count % 4 == 0) { + pin_on(pin1); + } + pin_on(pin3); + delay(delay_amt); + + ++count; + } +} 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); + } +} diff --git a/01-system-clock/src/vector.c b/01-system-clock/src/vector.c new file mode 100644 index 0000000..e69de29 --- /dev/null +++ b/01-system-clock/src/vector.c |