BusOneWire

Base OneWire bus interface to be used by devices. Concrete implementations in MCU drivers should be passed to drivers.

Ref.: Maxim’s Application Note 187 1-Wire Seach Algorithm Ref.: Maxim’s Appliaction Note 27 Understanding and using Cyclic Rendundancy Checks

Const

NoError* = 0;

ErrorNoDevice* = -1;

ErrorTimeout* = -2;

ErrorBus* = -3;

SendReset* = 1;

NoReset* = 2;

ReadSlot* = 0FFX;

NoRead* = 0FFH;

CMD_RSCRATCHPAD*    = 0BEX;

CMD_WSCRATCHPAD*    = 04EX;

CMD_CPYSCRATCHPAD*  = 048X;

CMD_RECEEPROM*      = 0B8X;

CMD_RPWRSUPPLY*     = 0B4X;

CMD_SEARCHROM*      = 0F0X;

CMD_READROM*        = 033X;

CMD_MATCHROM*       = 055X;

CMD_SKIPROM*        = 0CCX;

Types

Bus* = RECORD
        ROM_NO*: ARRAY 8 OF CHAR; (* 8-byte ROM addres last found device *)
        LastDiscrepancy*: UNSIGNED8;
        LastFamilyDiscrepancy*: UNSIGNED8;
        LastDeviceFlag*: BOOLEAN;
        error*: INTEGER; (* last transfer error code or NoError if success *)
        timeout*: UNSIGNED32; (* transfere timeout in ms. 0 or lower disable timeout check *)
    END;

Procedures

Bus.Enable

Enable 1-wire bus

PROCEDURE (VAR bus- : Bus) Enable*;

Bus.Disable

Disable 1-wire bus

PROCEDURE (VAR bus- : Bus) Disable*;

Bus.Reset

Send reset slot and return true if devices is present on bus

PROCEDURE (VAR bus : Bus) Reset*(): BOOLEAN;

Bus.WriteBit

Write bit to 1-wire bus

PROCEDURE (VAR bus- : Bus) WriteBit*(bit : BOOLEAN);

Bus.ReadBit

Read bit from 1-wire bus

PROCEDURE (VAR bus- : Bus) ReadBit*(): BOOLEAN;

Bus.SendReceive

Send and optinal receive data on 1-wire bus * sendReset : Send reset signal at the start. SendReset or NoReset. * cmd : Address to array of bytes commands. Use ReadSlot to specify reading. * clen : Length of command array. * data : Address to optional array of read buffer. * dlen : Length of read buffer. * rStart : Index for reading to start (from 0). NoRead to disable reading.

Return TRUE if no error occured.

PROCEDURE (VAR bus : Bus) SendReceive*(sendReset : INTEGER; cmd : ADDRESS; clen : LENGTH; data : ADDRESS; dlen, rStart: LENGTH): BOOLEAN;

Bus.ResetSearch

Reset ROM search

PROCEDURE (VAR bus : Bus) ResetSearch*;

Bus.Search

Search ROM Ref. Maxim APPLICATION NOTE 187

PROCEDURE (VAR bus : Bus) Search*(cmd : BYTE): BOOLEAN;

Bus.Next

Find next device on 1-wire bus

PROCEDURE (VAR bus : Bus) Next*(): BOOLEAN;

Bus.ReadROM

Write ROM to memory area

PROCEDURE (VAR bus : Bus) ReadROM*(adr : ADDRESS);

Bus.GetROM

Write ROM to array

PROCEDURE (VAR bus : Bus) GetROM*(VAR x : ARRAY OF BYTE);

Crc8

Calculate (MAXIM-DOW) CRC8 of memory array

PROCEDURE Crc8*(adr : ADDRESS; len : LENGTH): CHAR;

Crc16

TODO : Verify if working crrectly

PROCEDURE Crc16*(adr : ADDRESS; len : LENGTH): UNSIGNED16;