restructuring

F1:F103/SI7005_HTU21D/htu21d.c

@@ -0,0 +1,155 @@
+/*
+ * This file is part of the si7005 project.
+ * Copyright 2021 Edward V. Emelianov <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 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 <http://www.gnu.org/licenses/>.
+ */
+
+#include "htu21d.h"
+#include "i2c.h"
+
+#define DEVID  (0x40)
+
+#ifdef EBUG
+#include "usb.h"
+#include "proto.h"
+#define DBG(x)  do{USB_send(x);}while(0)
+#else
+#define DBG(x)
+#endif
+
+// read with no hold master!
+#define HTU21_READ_TEMP     (0xF3)
+#define HTU21_READ_HUMID    (0xF5)
+#define HTU21_READ_REG      (0xE7)
+#define HTU21_WRITE_REG     (0xE6)
+#define HTU21_SOFT_RESET    (0xFE)
+// status mask & val
+#define HTU21_STATUS_MASK   (0x03)
+#define HTU21_HUMID_FLAG    (0x02)
+// user reg fields
+#define HTU21_REG_VBAT      (0x40)
+#define HTU21_REG_D1        (0x80)
+#define HTU21_REG_D0        (0x01)
+#define HTU21_REG_HTR       (0x04)
+#define HTU21_REG_ODIS      (0x02)
+
+typedef enum{
+	RELAX = 0,
+	WAITFORT,       // T
+	WAITFORH        // humidity
+} HTU21D_state;
+
+static HTU21D_state state = RELAX;
+static HTU21D_status htustatus = HTU21D_RELAX;
+static uint16_t TH; // data for T or H
+
+HTU21D_status HTU21D_get_status(){
+    return htustatus;
+}
+
+//output in Cx10
+int32_t HTU21D_getT(){
+    DBG("HTU getT\n");
+    htustatus = HTU21D_RELAX;
+    if(TH & HTU21_HUMID_FLAG) return -5000; // humidity measured
+    uint32_t a = TH & 0xFFFC;
+    a *= 17572;
+    a >>= 16;
+    int32_t val = (a - 4685)/10;
+    return val;
+}
+
+//output in %x10
+uint32_t HTU21D_getH(){
+    DBG("HTU getH\n");
+    htustatus = HTU21D_RELAX;
+    if(!(TH & HTU21_HUMID_FLAG)) return 5000; // temperature measured
+    uint32_t a = TH & 0xFFFC;
+    a *= 1250;
+    a >>= 16;
+    a -= 60;
+    return a;
+}
+
+void HTU21D_setup(){
+    DBG("HTU setup\n");
+    htustatus = HTU21D_RELAX;
+    state = RELAX;
+	i2c_setup();
+	i2c_set_addr7(DEVID);
+}
+
+
+#define SHIFTED_DIVISOR 0x988000    //This is the 0x0131 polynomial shifted to farthest left of three bytes
+// check CRC, return 0 if all OK
+static uint32_t htu_check_crc(uint8_t *crc){
+    DBG("HTU check CRC\n");
+    uint32_t remainder = (crc[0] << 16) | (crc[1] << 8) | crc[2];
+    uint32_t divsor = (uint32_t)SHIFTED_DIVISOR;
+    int i;
+    for(i = 0; i < 16; i++) {
+        if (remainder & (uint32_t)1 << (23 - i))
+            remainder ^= divsor;
+        divsor >>= 1;
+    }
+    return remainder;
+}
+
+static int htusendcmd(uint8_t cmd){
+    DBG("htu cmd\n");
+    if(state != RELAX) return 1;
+    htustatus = HTU21D_BUSY;
+    if(I2C_OK != i2c_7bit_send_onebyte(cmd, 1)){
+        htustatus = HTU21D_ERR;
+        DBG("htu read err\n");
+        return 1;
+    }
+    return 0;
+}
+
+int HTU21D_cmdT(){
+    DBG("htu read T\n");
+    if(htusendcmd(HTU21_READ_TEMP)) return 1;
+    state = WAITFORT;
+    return 0;
+}
+
+int HTU21D_cmdH(){
+    DBG("htu read H\n");
+    if(htusendcmd(HTU21_READ_HUMID)) return 1;
+    state = WAITFORH;
+    return 0;
+}
+
+void HTU21D_process(){
+    uint8_t d[3];
+    if(state == RELAX) return;
+	if(state == WAITFORH || state == WAITFORT){ // poll RDY
+        if(I2C_OK != i2c_7bit_receive(d, 3)) return; // NACKed
+        DBG("HTU got H or T:");
+        DBG(u2str(d[0])); DBG(", ");
+        DBG(u2str(d[1])); DBG(", ");
+        DBG(u2str(d[2])); DBG("\n");
+        if(htu_check_crc(d)){
+            htustatus = HTU21D_ERR;
+            DBG("CRC failed\n");
+            state = RELAX;
+            return;
+        }
+        TH = (d[0] << 8) | d[1];
+        htustatus = (state == WAITFORH) ? HTU21D_HRDY : HTU21D_TRDY;
+        state = RELAX;
+    }
+}