EPC120 EPC [Espros Photonics corp], EPC120 Datasheet - Page 21

• Manufacturer Part Number: EPC120
• Description: Fully integrated Light-Barrier Chips with 2-Wire Bus Interface
• Manufacturer: EPC [Espros Photonics corp]

Command READ
Command WRITE
Command PROG
Returned Results
© 2011 ESPROS Photonics Corporation
Characteristics subject to change without notice
The RAM and ROM can be read by the command READ. The command is extended by the register address.
The bit N indicates whether a new result has been received (broadcast mode). D
data.
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.
The command PROG transfers the data from the RAM register to the corresponding ROM register. See chapter Address Programming for a
detailed description.
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.
This document is confidential and protected by law and international trades. It must not be shown to any third party nor be copied in any form without our written permission
File:
<Timming SPI read command 1>
SCK
CS
SI
Data Bits
D
D
5
0
… D
… D
N
N
20
4
Table 10: Result of a READ command
D
Function
Indicates, if new data is available
5 bit register address
16 bit returned data (one complete register)
0
N
0
1
Figure 20: Timing Result Data
D
1
Values
no new data available
new data available
D
2
21
D
3
D
4
0
...D
4
D
contains the address, D
5
.
D
2 0
<LST>
11
...D
Datasheet epc12x - V2.1
20
contains the returned
www.espros.ch
10.09.2010
Page 1
epc120