/* * This file is part of the libopencm3 project. * * Copyright (C) 2010 Thomas Otto * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program 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 General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see . */ #include #include #include #include #include #include "stts75.h" void usart_setup(void) { /* Enable clocks for GPIO port A (for GPIO_USART1_TX) and USART1. */ rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_IOPAEN); rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_USART1EN); /* Setup GPIO pin GPIO_USART1_TX/GPIO9 on GPIO port A for transmit. */ gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO_USART1_TX); /* Setup UART parameters. */ usart_set_baudrate(USART1, 115200, rcc_ppre2_frequency); usart_set_databits(USART1, 8); usart_set_stopbits(USART1, USART_STOPBITS_1); usart_set_mode(USART1, USART_MODE_TX_RX); usart_set_parity(USART1, USART_PARITY_NONE); usart_set_flow_control(USART1, USART_FLOWCONTROL_NONE); /* Finally enable the USART. */ usart_enable(USART1); } void gpio_setup(void) { /* Enable GPIOB clock. */ rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_IOPBEN); /* Set GPIO6/7 (in GPIO port B) to 'output push-pull' for the LEDs. */ gpio_set_mode(GPIOB, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO6); gpio_set_mode(GPIOB, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO7); } void i2c_setup(void) { /* Enable clocks for I2C2 and AFIO. */ rcc_peripheral_enable_clock(&RCC_APB1ENR, RCC_APB1ENR_I2C2EN); rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_AFIOEN); /* Set alternate functions for the SCL and SDA pins of I2C2. */ gpio_set_mode(GPIOB, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_ALTFN_OPENDRAIN, GPIO_I2C2_SCL | GPIO_I2C2_SDA); /* Disable the I2C before changing any configuration. */ i2c_peripheral_disable(I2C2); /* APB1 is running at 36MHz. */ i2c_set_clock_frequency(I2C2, I2C_CR2_FREQ_36MHZ); /* 400KHz - I2C Fast Mode */ i2c_set_fast_mode(I2C2); /* * fclock for I2C is 36MHz APB2 -> cycle time 28ns, low time at 400KHz * incl trise -> Thigh= 1600ns; CCR= tlow/tcycle= 0x1C,9; * datasheet suggests 0x1e. */ i2c_set_ccr(I2C2, 0x1e); /* * fclock for I2C is 36MHz -> cycle time 28ns, rise time for * 400KHz => 300ns and 100KHz => 1000ns; 300ns/28ns = 10; * incremented by 1 -> 11. */ i2c_set_trise(I2C2, 0x0b); /* * This is our slave address - needed only if we want to receive from * other masters. */ i2c_set_own_7bit_slave_address(I2C2, 0x32); /* If everything is configured -> enable the peripheral. */ i2c_peripheral_enable(I2C2); } int main(void) { int i = 0; u16 temperature; rcc_clock_setup_in_hse_16mhz_out_72mhz(); gpio_setup(); usart_setup(); i2c_setup(); gpio_clear(GPIOB, GPIO7); /* LED1 on */ gpio_set(GPIOB, GPIO6); /* LED2 off */ /* Send a message on USART1. */ usart_send(USART1, 's'); usart_send(USART1, 't'); usart_send(USART1, 'm'); usart_send(USART1, '\r'); usart_send(USART1, '\n'); stts75_write_config(I2C2, STTS75_SENSOR0); stts75_write_temp_os(I2C2, STTS75_SENSOR0, 0x1a00); /* 26 degrees */ stts75_write_temp_hyst(I2C2, STTS75_SENSOR0, 0x1a00); temperature = stts75_read_temperature(I2C2, STTS75_SENSOR0); /* Send the temperature as binary over USART1. */ for (i = 15; i >= 0 ; i--) { if (temperature & (1 << i)) usart_send(USART1, '1'); else usart_send(USART1, '0'); } usart_send(USART1, '\r'); usart_send(USART1, '\n'); gpio_clear(GPIOB, GPIO6); /* LED2 on */ while(1); /* Halt. */ return 0; }