Galep-4 Help

Real Time Clock DS1687 by Dallas Semiconductor

Program functions

Read

All registers, User and Extended RAM are read into the buffer according to the Memory mapping Table.

Program

All writeable registers, User and Extended RAM are programmed with data from the buffer according to the Memory mapping Table.

Compare

All writeable registers, User and Extended RAM are compared with data in the buffer according to the Memory mapping Table.

Erase

The Timekeeping and Control Registers are programmed as follows:

Register:

Value:

80h

38h

40h

The User and Extended RAM is filled with FFh value.

Blank Check

All writeable registers, User and Extended RAM are checked for the empty value (see 'Erase').

Note 1:	For Program/Erase the device will first be 'frozen' by setting the bit 7 of Control Register B (SET) to '1' and after programming and verifying it will be set to value defined by the user for 'Program' or kept on '1' for 'Erase'.
Note 2:	For 'Program', 'Compare', 'Erase' and 'Blank Check' all the readonly registers - Ch, Dh, 40h (Model Number), 41h-46h (Serial Numbers), 47h (CRC), 4Eh (RTC Address-2) and 4Fh (RTC Address-3) are ignored and not programmed/verified. In addition at 'Compare' and 'Blank Check' bit 5 of the Control Register A (DV1) is ignored and not verified.
Note 3:	Though bit 5 of the Control Register A (DV1) can be programmed to '0', - it will automatically be set to '1' by the device after restart.
Note 4:	There is no checking against incorrect values during programming, so the user must take care of this.

Memory mapping Table