Instructions

247 C-Control Pro IDE

5.6.3 Clock_SetTime

Clock Functions

Syntax

void Clock_SetTime(byte hour, byte min, byte sec, char corr);

Sub Clock_SetTime(hour As Byte, min As Byte, sec As Byte, corr As Char)

Description

Sets the time of the internal software clock. For a description of the correction factor refer to chapter Clock.

The correction factor is unused in the AVR32Bit, you can specify any value there.

Parameter

hour Hour

min Minute

sec Second

corr Correction Factor

5.7 DCF 77

All DCF routines are realized in library "LCD_Lib.cc". For use of this function the library

"DCF_Lib.cc" has to be tied into the project.

RTC with DCF 77 Time Synchronization

The DCF 77 Time Signal

The logical informations (time informations) are transmitted in addition to the normal frequency (car-

rier frequency of the transmitter, i. e. 77.5 kHz). This is performed by negative modulation of the sig-

nal (decrease of carrier amplitude to 25%). The start of the decrease lies at the respective beginning

of the seconds 0 … 58 within a minute. In second 59 there is no decrease, so the following second

mark can indicate the beginning of a minute and the receiver can be synchronized. The sign duration

yields the logical value of the signs: 100 ms are "0", 200 ms are "1". Because of this there are 59

bits for informations available within one minute. From these the second marks 1 through 14 are

used for operation informations which are not meant for DCF77 users. The second marks 15 through

19 indicate the transmitter antenna, the time zone and will give notice of coming time changes.

From second 20 through 58 the time information for the respective following minute will be transmit-

ted serially in from of BCD numbers, whereby in any case the least significant bit will be the start bit.

Bits

Meaning

Start bit (in any case "1")

21 - 27

Minute