User manual

mikroPascal PRO for PIC32
MikroElektronika
345
OneWire Library
The OneWire library provides routines for communication via the Dallas OneWire protocol, for example with DS18x20
digital thermometer. OneWire is a Master/Slave protocol, and all communication cabling required is a single wire.
OneWire enabled devices should have open collector drivers (with single pull-up resistor) on the shared data line.
Slave devices on the OneWire bus can even get their power supply from data line. For detailed schematic see device
datasheet.
Some basic characteristics of this protocol are:
- single master system,
- low cost,
- low transfer rates (up to 16 kbps),
- fairly long distances (up to 300 meters),
- small data transfer packages.
Each OneWire device also has a unique 64-bit registration number (8-bit device type, 48-bit serial number and 8-bit
CRC), so multiple slaves can co-exist on the same bus.
Important :
- Oscillator frequency Fosc needs to be at least 4MHz in order to use the routines with Dallas digital thermometers.
- This library implements time-based activities, so interrupts need to be disabled when using OneWire library.
Library Routines
- Ow_Reset
- Ow_Read
- Ow_Write
HW Connection
Pin diagram of MMC memory card