Add i2c eeprom example.

.gitignore

@@ -4,3 +4,4 @@
 *.hex
 *.bin
 *.map
+.gdb_config_bmp

README.md

@@ -22,6 +22,10 @@ The board presents itself as a serial port (CDC). It echoes back what it receive
 
 L052 only. This is the DFU bootloader that I use on the bat boards with L052. More info about it on [the bat board] main page.
 
+### i2c_eep
+
+Writes a few bytes, then reads a few bytes, from a standard I2C EEPROM. The bytes read are printed over USART (on PA9/PA10). Connections and address can be seen in the code (different setups for F0 and L0).
+
 ## General setup notes
 
 You are expected to a C compiler (for ARM) and some development tools (e.g. make and git) installed and ready to use. You can get a [toolchain from arm.com]; or use one provided by your system package manager (if you're on a normal system like some linux, bsd or mac). For the development tools, use your package manager.

i2c_eep/Makefile.f0

@@ -0,0 +1,38 @@
+##
+## This file is part of the libopencm3 project.
+##
+## Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
+##
+## This library is free software: you can redistribute it and/or modify
+## it under the terms of the GNU Lesser General Public License as published by
+## the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+##
+## This library is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU Lesser General Public License for more details.
+##
+## You should have received a copy of the GNU Lesser General Public License
+## along with this library.  If not, see <http://www.gnu.org/licenses/>.
+##
+
+BINARY = i2c_eep
+
+OBJS += serial_helper.o
+
+OPENCM3_DIR=../libopencm3
+LDSCRIPT = $(OPENCM3_DIR)/lib/stm32/f0/stm32f07xzb.ld
+
+include ../common.f0.mk
+
+BMP_PORT = /dev/cu.usbmodemE0BABAF1
+
+.gdb_config_bmp:
+	echo > .gdb_config_bmp "file $(BINARY).elf\ntarget extended-remote $(BMP_PORT)\nmonitor version\nmonitor swdp_scan\nattach 1\nload\nbreak main\nc\n"
+
+debug_bmp: .gdb_config_bmp $(BINARY).elf
+	cgdb -d $(GDB) -- \
+		   --command=.gdb_config_bmp \
+		   $(BINARY).elf
+

i2c_eep/Makefile.l0

@@ -0,0 +1,38 @@
+##
+## This file is part of the libopencm3 project.
+##
+## Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
+##
+## This library is free software: you can redistribute it and/or modify
+## it under the terms of the GNU Lesser General Public License as published by
+## the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+##
+## This library is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU Lesser General Public License for more details.
+##
+## You should have received a copy of the GNU Lesser General Public License
+## along with this library.  If not, see <http://www.gnu.org/licenses/>.
+##
+
+BINARY = i2c_eep
+
+OBJS += serial_helper.o
+
+OPENCM3_DIR=../libopencm3
+LDSCRIPT = $(OPENCM3_DIR)/lib/stm32/l0/stm32l0xx8.ld
+
+include ../common.l0.mk
+
+BMP_PORT = /dev/cu.usbmodemE0BABAF1
+
+.gdb_config_bmp:
+	echo > .gdb_config_bmp "file $(BINARY).elf\ntarget extended-remote $(BMP_PORT)\nmonitor version\nmonitor swdp_scan\nattach 1\nload\nbreak main\nc\n"
+
+debug_bmp: .gdb_config_bmp $(BINARY).elf
+	cgdb -d $(GDB) -- \
+		   --command=.gdb_config_bmp \
+		   $(BINARY).elf
+

i2c_eep/Makefile.l0btld

@@ -0,0 +1,29 @@
+##
+## This file is part of the libopencm3 project.
+##
+## Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
+##
+## This library is free software: you can redistribute it and/or modify
+## it under the terms of the GNU Lesser General Public License as published by
+## the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+##
+## This library is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU Lesser General Public License for more details.
+##
+## You should have received a copy of the GNU Lesser General Public License
+## along with this library.  If not, see <http://www.gnu.org/licenses/>.
+##
+
+BINARY = i2c_eep
+
+OBJS += serial_helper.o
+
+OPENCM3_DIR=../libopencm3
+LDSCRIPT = ../l052-bldr.ld
+DEFS += -DBOOTLOADER8K
+
+include ../common.l0.mk
+

i2c_eep/i2c_eep.c

@@ -0,0 +1,201 @@
+#include <libopencm3/stm32/rcc.h>
+#include <libopencm3/stm32/flash.h>
+#include <libopencm3/stm32/gpio.h>
+#include <libopencm3/stm32/i2c.h>
+
+#include <libopencm3/stm32/usart.h>
+#include "serial_helper.h"
+
+
+static void usart_setup(void)
+{
+	/* Enable clocks for GPIO port A (for GPIO_USART1_TX) and USART1. */
+	rcc_periph_clock_enable(RCC_GPIOA);
+	rcc_periph_clock_enable(RCC_USART1);
+
+#if defined(STM32F0)
+	/* USART1 pins: PA9/TX PA10/RX */
+	gpio_mode_setup(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO9|GPIO10);
+	gpio_set_af(GPIOA, GPIO_AF1, GPIO9|GPIO10);
+#elif defined(STM32L0)
+	/* USART1 pins: PA9/TX PA10/RX */
+	gpio_set_af(GPIOA, GPIO_AF4, GPIO9|GPIO10);
+	gpio_set_output_options(GPIOA, GPIO_OTYPE_OD, GPIO_OSPEED_HIGH, GPIO9|GPIO10);
+	gpio_mode_setup(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO9|GPIO10);
+#endif
+
+	/* Setup UART parameters. */
+	usart_set_baudrate(USART1, 115200);
+	usart_set_databits(USART1, 8);
+	usart_set_parity(USART1, USART_PARITY_NONE);
+	usart_set_stopbits(USART1, USART_STOPBITS_1);
+	//usart_set_stopbits(USART1, USART_CR2_STOP_1_0BIT);
+	usart_set_mode(USART1, USART_MODE_TX_RX);
+	usart_set_flow_control(USART1, USART_FLOWCONTROL_NONE);
+
+	/* Finally enable the USART. */
+	usart_enable(USART1);
+}
+
+static void gpio_setup(void)
+{
+	rcc_periph_clock_enable(RCC_GPIOA);
+
+	/* Set PA15 for LED */
+	gpio_mode_setup(GPIOA, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO15);
+}
+
+static void i2c_setup(void)
+{
+	uint32_t i2c;
+#if defined(STM32F0)
+	/* Enable clocks for I2C2. */
+	rcc_periph_clock_enable(RCC_I2C2);
+	rcc_periph_clock_enable(RCC_GPIOB);
+
+	/* Set alternate functions for the SCL and SDA pins of I2C2. */
+	gpio_set_af(GPIOB, GPIO_AF1, GPIO10|GPIO11);
+	gpio_mode_setup(GPIOB, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO10|GPIO11);
+
+	i2c = I2C2;
+
+#elif defined(STM32L0)
+	/* Enable clocks for I2C1. */
+	rcc_periph_clock_enable(RCC_I2C1);
+	rcc_periph_clock_enable(RCC_GPIOB);
+
+	/* Set alternate functions for the SCL and SDA pins of I2C2. */
+	gpio_set_af(GPIOB, GPIO_AF4, GPIO8|GPIO9);
+	gpio_set_output_options(GPIOB, GPIO_OTYPE_OD, GPIO_OSPEED_HIGH, GPIO8|GPIO9);
+	gpio_mode_setup(GPIOB, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO8|GPIO9);
+
+	i2c = I2C1;
+#endif /* STM32L0 */
+	i2c_reset(i2c);
+
+	/* Disable the I2C before changing any configuration. */
+	i2c_peripheral_disable(i2c);
+
+	/* setup from libopencm3-examples */
+	i2c_enable_analog_filter(i2c);
+	i2c_set_digital_filter(i2c, I2C_CR1_DNF_DISABLED);
+	i2c_set_speed(i2c, i2c_speed_sm_100k, 8);
+	i2c_enable_stretching(i2c);
+	i2c_set_7bit_addr_mode(i2c);
+
+	/* If everything is configured -> enable the peripheral. */
+	i2c_peripheral_enable(i2c);
+}
+
+
+#if defined(STM32L0)
+static void clock_setup_l0(void)
+{
+	/* After a reset, the system uses MSI@2.1MHz. */
+	/* end result: 32MHz PLLVCO from HSI16,
+	 *	 no system/periph clock divide.
+	 */
+
+	/* increase the latency to 1 wait state (we'll be speeding up) */
+	flash_set_ws(1);
+
+	/* turn on HSI16 */
+	rcc_osc_on(RCC_HSI16);
+	rcc_wait_for_osc_ready(RCC_HSI16);
+
+	/* run AHB, APB1, APB2 at full speed */
+	rcc_set_hpre(RCC_CFGR_HPRE_NODIV);
+	rcc_set_ppre1(RCC_CFGR_PPRE1_NODIV);
+	rcc_set_ppre2(RCC_CFGR_PPRE2_NODIV);
+
+	/* turn off PLL and wait for it to fully stop */
+	rcc_osc_off(RCC_PLL);
+	while (RCC_CR & RCC_CR_PLLRDY);
+
+	/* set PLL source to HSI16 */
+	RCC_CFGR &= ~(1<<16); // RCC_CFGR_PLLSRC
+
+	/* set up PLL */
+	rcc_set_pll_multiplier(RCC_CFGR_PLLMUL_MUL4);
+	rcc_set_pll_divider(RCC_CFGR_PLLDIV_DIV2);
+
+	/* turn on and switch to PLL */
+	rcc_osc_on(RCC_PLL);
+	rcc_wait_for_osc_ready(RCC_PLL);
+	rcc_set_sysclk_source(RCC_PLL);
+
+	rcc_ahb_frequency = 32000000;
+	rcc_apb1_frequency = 32000000;
+	rcc_apb2_frequency = 32000000;
+}
+#endif /* STM32L0 */
+
+int main(void)
+{
+#if defined(BOOTLOADER8K)
+#	define SCB_VTOR MMIO32(0xE000ED08)
+	SCB_VTOR = (uint32_t) 0x08002000;
+#endif /* BOOTLOADER8K */
+
+#if defined(STM32F0)
+	uint32_t i2c = I2C2;
+#elif defined(STM32L0)
+	uint32_t i2c = I2C1;
+#endif /* STM32L0 */
+	uint8_t eeprom_addr = 0x50;
+
+#if defined(STM32F0)
+	rcc_clock_setup_in_hsi_out_48mhz();
+#elif defined(STM32L0)
+	clock_setup_l0();
+#endif
+	gpio_setup();
+	usart_setup();
+	i2c_setup();
+
+	/* Send a message on USART1. */
+	pstr("stm\r\n");
+
+	uint8_t temp[10];
+	uint8_t wb[2];
+
+	// one byte addresses for smaller epproms
+	temp[0] = 0;
+	// bytes to write
+	temp[1] = 0x11;
+	temp[2] = 0x22;
+	temp[3] = 0x33;
+
+	// write
+	i2c_transfer7(i2c, eeprom_addr, temp, 4, NULL, 0);
+
+	uint32_t t;
+	// the pause needs to be long enough for the eeprom to finish
+	// writing the data above; otherwise the 'read' call below
+	// hangs
+	t = 500000;
+	while(t-- > 0)
+		__asm__("nop");
+
+	// two byte addresses for bigger eeproms (change also transfer7 call!)
+	//wb[0] = (uint8_t)( 0 >>8);
+	//wb[1] = (uint8_t)( 0 &0xFF);
+	// one byte addresses for smaller epproms (change also transfer7 call!)
+	wb[0] = 0;
+
+	// read
+	i2c_transfer7(i2c, eeprom_addr, wb, 1, temp, 10);
+
+	gpio_set(GPIOA, GPIO15); /* LED on */
+
+	uint8_t i;
+	for(i=0; i<10; i++)
+		phex(temp[i]);
+	pent();
+
+	while (1); /* Halt. */
+
+	return 0;
+}
+
+// vim: tabstop=4:shiftwidth=4:noexpandtab

i2c_eep/serial_helper.c

@@ -0,0 +1,39 @@
+#include "serial_helper.h"
+
+void phex4(uint8_t c) {
+	usart_send_blocking(P_USART, (uint8_t)(c + ((c < 10) ? '0' : 'A' - 10)));
+}
+
+void phex(uint8_t c) {
+	phex4((c>>4));
+	phex4((c&15));
+}
+
+void phex16(uint16_t c) {
+	phex((uint8_t)(c>>8));
+	phex((uint8_t)c);
+}
+
+void phex24(uint32_t c) {
+	phex16((uint16_t)((c>>8)&0xFFFF));
+	phex((uint8_t)c);
+}
+
+void phex32(uint32_t c) {
+	phex16((uint16_t)(c>>16));
+	phex16((uint16_t)(c&0xFFFF));
+}
+
+void pent(void) {
+	usart_send_blocking(P_USART, '\r');
+	usart_send_blocking(P_USART, '\n');
+}
+
+void pstr(char *s) {
+	uint16_t i = 0;
+	while(s[i]) {
+		usart_send_blocking(P_USART, (uint8_t)(s[i++]));
+	}
+}
+
+// vim: tabstop=4:shiftwidth=4:noexpandtab

i2c_eep/serial_helper.h

@@ -0,0 +1,17 @@
+#ifndef SERIAL_HELPER_H
+#define SERIAL_HELPER_H
+
+#include <libopencm3/stm32/usart.h>
+
+#define P_USART USART1
+
+void phex4(uint8_t c);
+void phex(uint8_t c);
+void phex16(uint16_t c);
+void phex24(uint32_t c);
+void phex32(uint32_t c);
+void pent(void);
+
+void pstr(char *s);
+
+#endif /* SERIAL_HELPER_H */

libopencm3.rules.mk

@@ -72,7 +72,7 @@ STFLASH		= $(shell which st-flash)
 STYLECHECK	:= /checkpatch.pl
 STYLECHECKFLAGS	:= --no-tree -f --terse --mailback
 STYLECHECKFILES	:= $(shell find . -name '*.[ch]')
-OPT		:= -Os
+OPT		?= -Os
 CSTD		?= -std=c99