epc120
Command READ
The RAM and ROM can be read by the command READ. The command is extended by the register address.
CS
SCK
SI
N
D0
D1
D2
D3
D4
D20
D5
Figure 20: Timing Result Data
The bit N indicates whether a new result has been received (broadcast mode). D0...D4 contains the address, D11...D20 contains the returned
data.
Data Bits
N
Function
Indicates, if new data is available
N
0
1
Values
no new data available
new data available
D0 … D4
D5 … D20
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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