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Update dhtreader.c to be compatible with Python 3.x C API #68

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Update dhtreader.c to be compatible with Python 3.x C API #68

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255 changes: 141 additions & 114 deletions Adafruit_DHT_Driver_Python/dhtreader.c
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Original file line number Diff line number Diff line change
@@ -1,12 +1,12 @@
/* Python module for DHT temperature/humidity sensors
*
* Modified by Qingping Hou from DHT reader example, original header:
*
* How to access GPIO registers from C-code on the Raspberry-Pi
* Example program
* 15-January-2012
* Dom and Gert
*/
/* Python module for DHT temperature/humidity sensors
*
* Modified by Qingping Hou from DHT reader example, original header:
*
* How to access GPIO registers from C-code on the Raspberry-Pi
* Example program
* 15-January-2012
* Dom and Gert
*/


/* for usleep */
Expand Down Expand Up @@ -38,142 +38,169 @@

int readDHT(int type, int pin, float *temp_p, float *hum_p)
{
int counter = 0;
int laststate = HIGH;
int i = 0;
int j = 0;
int checksum = 0;
int counter = 0;
int laststate = HIGH;
int i = 0;
int j = 0;
int checksum = 0;
#ifdef DEBUG
int bitidx = 0;
int bits[250];
int bitidx = 0;
int bits[250];
#endif
int data[100];

// Set GPIO pin to output
bcm2835_gpio_fsel(pin, BCM2835_GPIO_FSEL_OUTP);

bcm2835_gpio_write(pin, HIGH);
usleep(500000); // 500 ms
bcm2835_gpio_write(pin, LOW);
usleep(20000);

bcm2835_gpio_fsel(pin, BCM2835_GPIO_FSEL_INPT);

data[0] = data[1] = data[2] = data[3] = data[4] = 0;

// wait for pin to drop?
while (bcm2835_gpio_lev(pin) == 1) {
usleep(1);
}

// read data!
for (i = 0; i < MAXTIMINGS; i++) {
counter = 0;
while ( bcm2835_gpio_lev(pin) == laststate) {
counter++;
//nanosleep(1); // overclocking might change this?
if (counter == 1000)
break;
}
laststate = bcm2835_gpio_lev(pin);
if (counter == 1000) break;
int data[100];

// Set GPIO pin to output
bcm2835_gpio_fsel(pin, BCM2835_GPIO_FSEL_OUTP);

bcm2835_gpio_write(pin, HIGH);
usleep(500000); // 500 ms
bcm2835_gpio_write(pin, LOW);
usleep(20000);

bcm2835_gpio_fsel(pin, BCM2835_GPIO_FSEL_INPT);

data[0] = data[1] = data[2] = data[3] = data[4] = 0;

// wait for pin to drop?
while (bcm2835_gpio_lev(pin) == 1) {
usleep(1);
}

// read data!
for (i = 0; i < MAXTIMINGS; i++) {
counter = 0;
while ( bcm2835_gpio_lev(pin) == laststate) {
counter++;
//nanosleep(1); // overclocking might change this?
if (counter == 1000)
break;
}
laststate = bcm2835_gpio_lev(pin);
if (counter == 1000) break;
#ifdef DEBUG
bits[bitidx++] = counter;
bits[bitidx++] = counter;
#endif

if ((i>3) && (i%2 == 0)) {
// shove each bit into the storage bytes
data[j/8] <<= 1;
if (counter > 200)
data[j/8] |= 1;
j++;
}
}
if ((i>3) && (i%2 == 0)) {
// shove each bit into the storage bytes
data[j/8] <<= 1;
if (counter > 200)
data[j/8] |= 1;
j++;
}
}

#ifdef DEBUG
for (int i=3; i<bitidx; i+=2) {
printf("bit %d: %d\n", i-3, bits[i]);
printf("bit %d: %d (%d)\n", i-2, bits[i+1], bits[i+1] > 200);
}
printf("Data (%d): 0x%x 0x%x 0x%x 0x%x 0x%x\n", j, data[0], data[1], data[2], data[3], data[4]);
for (int i=3; i<bitidx; i+=2) {
printf("bit %d: %d\n", i-3, bits[i]);
printf("bit %d: %d (%d)\n", i-2, bits[i+1], bits[i+1] > 200);
}
printf("Data (%d): 0x%x 0x%x 0x%x 0x%x 0x%x\n", j, data[0], data[1], data[2], data[3], data[4]);
#endif

if (j >= 39) {
checksum = (data[0] + data[1] + data[2] + data[3]) & 0xFF;
if (data[4] == checksum) {
/* yay! checksum is valid */
if (type == DHT11) {
/*printf("Temp = %d *C, Hum = %d \%\n", data[2], data[0]);*/
*temp_p = (float)data[2];
*hum_p = (float)data[0];
} else if (type == DHT22) {
*hum_p = data[0] * 256 + data[1];
*hum_p /= 10;

*temp_p = (data[2] & 0x7F)* 256 + data[3];
*temp_p /= 10.0;
if (data[2] & 0x80)
*temp_p *= -1;
/*printf("Temp = %.1f *C, Hum = %.1f \%\n", f, h);*/
}
return 0;
}
return -2;
}

return -1;
if (j >= 39) {
checksum = (data[0] + data[1] + data[2] + data[3]) & 0xFF;
if (data[4] == checksum) {
/* yay! checksum is valid */
if (type == DHT11) {
/*printf("Temp = %d *C, Hum = %d \%\n", data[2], data[0]);*/
*temp_p = (float)data[2];
*hum_p = (float)data[0];
} else if (type == DHT22) {
*hum_p = data[0] * 256 + data[1];
*hum_p /= 10;

*temp_p = (data[2] & 0x7F)* 256 + data[3];
*temp_p /= 10.0;
if (data[2] & 0x80)
*temp_p *= -1;
/*printf("Temp = %.1f *C, Hum = %.1f \%\n", f, h);*/
}
return 0;
}
return -2;
}

return -1;
}


// ========== Python integration ============

static PyObject *
dhtreader_init(PyObject *self, PyObject *args)
{
return Py_BuildValue("i", bcm2835_init());
return Py_BuildValue("i", bcm2835_init());
}

static PyObject *
dhtreader_read(PyObject *self, PyObject *args)
{
int type, dhtpin;
int type, dhtpin;

if (!PyArg_ParseTuple(args, "ii", &type, &dhtpin))
return NULL;
if (!PyArg_ParseTuple(args, "ii", &type, &dhtpin))
return NULL;

float t, h;
int re = readDHT(type, dhtpin, &t, &h);
float t, h;
int re = readDHT(type, dhtpin, &t, &h);

if (re == 0) {
return Py_BuildValue("(d,d)", t, h);
} else if (re == -1) {
if (re == 0) {
return Py_BuildValue("(d,d)", t, h);
} else if (re == -1) {
#ifdef DEBUG
printf("sensor read failed! not enough data received\n");
printf("sensor read failed! not enough data received\n");
#endif
} else if (re == -2) {
} else if (re == -2) {
#ifdef DEBUG
printf("sensor read failed! checksum failed!\n");
printf("sensor read failed! checksum failed!\n");
#endif
}
}

return Py_BuildValue("");
return Py_BuildValue("");
}


static PyMethodDef DHTReaderMethods[] = {
{"init", dhtreader_init, METH_VARARGS,
"initialize dht reader"},
{"read", dhtreader_read, METH_VARARGS,
"temperature and humidity from sensor"},
{NULL, NULL, 0, NULL} /* Sentinel */
{"init", dhtreader_init, METH_VARARGS,
"initialize dht reader"},
{"read", dhtreader_read, METH_VARARGS,
"temperature and humidity from sensor"},
{NULL, NULL, 0, NULL} /* Sentinel */
};

PyMODINIT_FUNC
initdhtreader(void)
{
PyObject *m;

m = Py_InitModule("dhtreader", DHTReaderMethods);
if (m == NULL)
return;
}


#if PY_MAJOR_VERSION >= 3
static struct PyModuleDef moduledef = {
PyModuleDef_HEAD_INIT,
"dhtreader", /* m_name */
"DHT reader module", /* m_doc */
-1, /* m_size */
DHTReaderMethods, /* m_methods */
NULL, /* m_reload */
NULL, /* m_traverse */
NULL, /* m_clear */
NULL, /* m_free */
};


PyMODINIT_FUNC
PyInit_dhtreader(void)
{
PyObject *m;
m = PyModule_Create(&moduledef);
if (m == NULL) {
return;
} else {
return m;
}
}
#else
PyMODINIT_FUNC
initdhtreader(void)
{
PyObject *m;

m = Py_InitModule("dhtreader", DHTReaderMethods);
if (m == NULL)
return;
}
#endif