Rainbow-electronics DS1305 Instrukcja Użytkownika Pobierz pdf (Strona 4)

DS1305

4 of 20

SDI (Serial Data Input) – When SPI communication is selected, the SDI pin is the serial data input for

the SPI bus. When 3-wire communication is selected, this pin must be tied to the SDO pin (the SDI and

SDO pins function as a single I/O pin when tied together).

SDO (Serial Data Output) – When SPI communication is selected, the SDO pin is the serial data output

for the SPI bus. When 3-wire communication is selected, this pin must be tied to the SDI pin (the SDI and

SDO pins function as a single I/O pin when tied together).

CE (Chip Enable) – The chip enable signal must be asserted high during a read or a write for both 3-

wire and SPI communication. This pin has an internal 55k pulldown resistor (typical).

INT0 (Interrupt 0 Output) – The INT0 pin is an active low output of the DS1305 that can be used as an

interrupt input to a processor. The INT0 pin can be programmed to be asserted by only Alarm 0 or can be

programmed to be asserted by either Alarm 0 or Alarm 1. The

INT0 pin remains low as long as the status

bit causing the interrupt is present and the corresponding interrupt enable bit is set. The

INT0 pin operates

when the DS1305 is powered by V

CC1

, V

CC2

, or V

BAT

. The INT0 pin is an open drain output and requires

an external pullup resistor.

INT1 (Interrupt 1 Output) – The INT1 pin is an active-low output of the DS1305 that can be used as an

interrupt input to a processor. The INT1 pin can be programmed to be asserted by Alarm 1 only. The

INT1 pin remains low as long as the status bit causing the interrupt is present and the corresponding

interrupt enable bit is set. The INT1 pin operates when the DS1305 is powered by V

CC1

, V

CC2

, or V

BAT

The INT1 pin is an open-drain output and requires an external pullup resistor.

Both INT0 and INT1 are open-drain outputs. The two interrupts and the internal clock continue to run

regardless of the level of V

(as long as a power source is present).

PF (Power-Fail Output) – The PF pin is used to indicate loss of the primary power supply (V

CC1

When V

CC1

is less than V

CC2

or is less than V

BAT

, the PF pin is driven low.

X1, X2 – Connections for a standard 32.768kHz quartz crystal. The internal oscillator is designed for

operation with a crystal having a specified load capacitance of 6pF. For more information on crystal

selection and crystal layout considerations, refer to Application Note 58, “Crystal Considerations with

Dallas Real-Time Clocks.” The DS1305 can also be driven by an external 32.768kHz oscillator. In this

configuration, the X1 pin is connected to the external oscillator signal and the X2 pin is floated.

1 2 3 4 5 6 7 8 9 ... 19 20

Komentarze do niniejszej Instrukcji

Brak uwag

Rainbow-electronics DS1305 Instrukcja Użytkownika Strona 4

Komentarze do niniejszej Instrukcji

Powiązane produkty i podręczniki dla Sprzęt komputerowy Rainbow-electronics DS1305