I am trying to comunicate with Temp/Humid module DHT11
However data pin should be pull up to 3.3 but while my RTL trying to comunicate with DHT11 throgh IO13 pin, Data line pull down to GND.
if GPIO can be inout port, then any one know how?
My RTL working fine in simulation with Vivado
As you are using DHT11 sensor, you should use Serial protocol i.e. UART RX line to sample the received values.
The DHT11 sensor works like following.
"Data line remains in high normally, then master in this case FPGA will start communication first. The the sensor will respond with temparature, humidity data".
See the following image of timing diagram.
The output given out by the data pin will be in the order of 8bit humidity integer data + 8bit the Humidity decimal data +8 bit temperature integer data + 8bit fractional temperature data +8 bit parity bit. To request the DHT11 module to send these data the I/O pin has to be momentarily made low and then held high as shown in the timing diagram below
It seems a waste to use such a sensor directly attached to a MiniZed. There are better sensors, that interface through more normal interfaces.
One typical approach to connect such a sensor, is to use two ports; one as input, and the other as output, and build yourself an interface. You'd have to check if the values below are appropriate (I've not read the DHT11 datasheet). With such an interface circuit, the controller (FPGA or microcontroller or otherwise, it's up to you) doesn't need to switch between input and output.
When a logic high is sent by the controller, the sensor line is pulled low. When a logic low is sent by the controller, the line is pulled up, and the remote sensor is free to pull the line low.
