epc120

Command READ

The RAM and ROM can be read by the command READ. The command is extended by the register address.

Figure 20: Timing Result Data

data.

Data Bits

Function

N

Indicates, if new data is available

N

Values

0

no new data available

1

new data available

5 bit register address

16 bit returned data (one complete register)

Table 10: Result of a READ command

Command WRITE

Data can be written into the RAM by using the command WRITE. The command is extended by the register address and the data. It is only

possible to write to registers if the corresponding register in the ROM has not been written yet. It is not possible to write directly to a ROM

register. If the data has to be stored into the ROM register, a subsequent command PROG has to be used.

Command PROG

The command PROG transfers the data from the RAM register to the corresponding ROM register. See chapter Address Programming for a

detailed description.

Returned Results

The results at pin SO depends on one of the previous commands and can be fetched by any command or just by toggling SCK while CS is

low (=NOP).

• The data is represented with the LSB first.

• After an SPI communication the data register is cleared.

• By holding the CS line to 0 it is possible to trigger on a positive edge of SO.

• If more clock toggles SCK are issued than data can be fetched, zeros are transmitted.

© 2011 ESPROS Photonics Corporation

Characteristics subject to change without notice

21

Datasheet epc12x - V2.1

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CS

SCK

SI

N

D

0

D

1

D

2

D

3

D

4

D

5

D

20