SA9604A

sames

7/20

Address locations A4 and A5 have been included to ensure compatibility with future

SAMES integrated circuit developments.

When CS is high, data input on pin DI is clocked into the device on the rising edge

of SCK. The data clocked into DI will comprise of 1 1 0 A5 A4 A3 A2 A1 A0, in this

order.

5.3 Data Output

After the least significant digit of the address has been entered on the rising edge

of SCK, the output DO goes low with falling edge of SCK. Each subsequent falling

edge transaction on the SCK pin will validate data of the register contents on pin DO.

The contents of each register consists of 24 bits of data output on pin D0, starting

with the most significant digit, D23.

5.4 Frequency Register

For the frequency register only bits D15 ... D0 are used for calculations. The upper

seven bits (D23 ... D17) must still be clocked out, as important frequency information

can be derived from these data bits.

Bit D17 changes with every rising edge of the mains voltage (25Hz square wave for

50Hz mains system). Bit D18 displays a frequency of D17/2 and D19 displays a

frequency of D17/4.

The phase error status may be ascertained from bits D20 and D21. The table below

may be used for this purpose:

D21

0

1

1

D20

0

0

1

No phase error

Phase sequence error (2 phase swapped)

Missing phase

Frequency data Bits

Description

The phase error status is merged on all three frequency registers.

Bits D16, D22 and D23 are not used.