restructuring

F0:F030,F042,F072/htu21d_nucleo/main.c

@@ -0,0 +1,124 @@
+/*
+ * main.c
+ *
+ * Copyright 2017 Edward V. Emelianoff <eddy@sao.ru, edward.emelianoff@gmail.com>
+ *
+ * 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 2 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+#include "stm32f0.h"
+#include "usart.h"
+#include "i2c.h"
+
+volatile uint32_t Tms = 0;
+
+/* Called when systick fires */
+void sys_tick_handler(void){
+    ++Tms;
+}
+
+static void gpio_setup(void){
+    // Set green led (PB3) as output
+    RCC->AHBENR |= RCC_AHBENR_GPIOBEN;
+    GPIOB->MODER = GPIO_MODER_MODER3_O;
+}
+
+void printi(int16_t val){
+    char buf[6], rbuf[5];
+    int l = 0, bpos = 0;
+    if(!val){
+        buf[0] = '0';
+        l = 1;
+    }else{
+        if(val < 0){
+            buf[0] = '-';
+            bpos = 1;
+            val = -val;
+        }
+        while(val){
+            rbuf[l++] = val % 10 + '0';
+            val /= 10;
+        }
+        int i;
+        bpos += l;
+        for(i = 0; i < l; ++i){
+            buf[--bpos] = rbuf[i];
+        }
+    }
+    while(ALL_OK != usart2_send_blocking(buf, l+bpos));
+}
+
+int main(void){
+    uint32_t lastT = 0;
+    int16_t L = 0;
+    int _1sec = 0, T_H = 0; // T_H - read t(1) or h(0)
+    uint32_t msctr = 0;
+    char *txt;
+    sysreset();
+    SysTick_Config(6000, 1);
+    gpio_setup();
+    usart2_setup();
+    i2c_setup();
+
+    while (1){
+        if(lastT > Tms || Tms - lastT > 499){
+            pin_toggle(GPIOB, 1<<3); // blink by onboard LED once per second
+            lastT = Tms;
+        }
+        if(usart2rx()){ // usart1 received data, store in in buffer
+            L = usart2_getline(&txt);
+            printi(L);
+            // do something with received data
+        }
+        if(L){ // text waits for sending
+            if(ALL_OK == usart2_send(txt, L)){
+                L = 0;
+            }
+        }
+        if(msctr != Tms){
+            msctr = Tms;
+            if(++_1sec >= 1000){ // once per 1 second
+                _1sec = 0;
+                // send H/T
+                uint8_t command = HTU21_READ_HUMID;
+                if(T_H) command = HTU21_READ_TEMP;
+                if(!htu_write_i2c(command))
+                    while(ALL_OK != usart2_send_blocking("Error!\n", 7));
+            }
+        }
+        // poll I2C
+        uint16_t val = 0;
+        if(htu_read_i2c(&val)){ // got data
+            if(T_H){
+                while(ALL_OK != usart2_send_blocking("Temperature: ", 13));
+                int16_t t = convert_temperature(val);
+                printi(t);
+                while(ALL_OK != usart2_send_blocking("/10 degrC\n", 10));
+            }else{
+                while(ALL_OK != usart2_send_blocking("Humidity: ", 10));
+                int16_t h = convert_humidity(val);
+                printi(h);
+                while(ALL_OK != usart2_send_blocking("/10 %\n", 6));
+            }
+            T_H = !T_H;
+        }else{
+            if(val) // CRC error
+                while(ALL_OK != usart2_send_blocking("CRC error!\n", 11));
+        }
+    }
+    return 0;
+}
+