MCP23017 and the db18b20

hi guys

is possible read db18b20 or dht22 sensor through mcp23017 expander?

all examples have seen online control led's, simple enough. how data 1 wire digital temperature sensor?

im trying port arduino esp8266 , have run out of pins. hens teeth.

any direction appreciated.

looking @ dht22 library

quote

// read 40 bits sent sensor.  each bit sent 50
    // microsecond low pulse followed variable length high pulse.  if the
    // high pulse ~28 microseconds it's 0 , if it's ~70 microseconds
    // it's 1. 

i doubt can kinds of speeds through i2c bus.

reading byte i2c bus requires addressing device (8 bits) , reading data (8 bits). 16 bits @ 400 khz (2.5 microseconds per bit) gives 40 microseconds transfer of 1 byte mcp microcontroller.

i don't know if can squeeze maximum speed mcp supports (1.7mhz) out of microcontroller.

does micro support hardware spi? speed? maybe can gain using spi version mcp23s17 (max clock 10mhz)?

Arduino Forum > Using Arduino > Microcontrollers > MCP23017 and the db18b20

arduino