zl50417 ETC-unknow, zl50417 Datasheet - Page 16

• Manufacturer Part Number: zl50417
• Description: Unmanaged 16-port 10/100m +2-port Ethernet Switch
• Manufacturer: ETC-unknow

16
2.3
The synchronous serial interface serves the function of configuring the ZL50417 not at boot time but via a PC. The
PC serves as master and the ZL50417 serves as slave. The protocol for the synchronous serial interface is nearly
identical to the I²C protocol. The main difference is that there is no acknowledgment bit after each byte of data
transferred.
The unmanaged ZL50417 uses a synchronous serial interface to program the internal registers. To reduce the
number of signals required, the register address, command and data are shifted in serially through the D0 pin.
STROBE- pin is used as the shift clock. AUTOFD- pin is used as data return path.
Each command consists of four parts.
•
•
•
•
Any command can be aborted in the middle by sending a ABORT pulse to the ZL50417.
A START command is detected when D0 is sampled high when STROBE- rise and D0 is sampled low when
STROBE- fall.
An ABORT command is detected when D0 is sampled low when STROBE- rise and D0 is sampled high when
STROBE- fall.
2.3.1
2.3.2
ZL50417
START pulse
Register Address
Read or Write command
Data to be written or read back
Synchronous Serial Interface
STROBE-
Write Command
Read Command
D0
STROBE-
AUTOFD-
START
D0
A0
START
A1
A0 A1 A2
A2
ADDRESS
...
ADDRESS
A9
...
A10
A9
Figure 3 - Write Command
A11
Figure 4 - Read Command
COMMAND
Zarlink Semiconductor Inc.
A10
W
A11
COMMAND
D0 D1 D2 D3 D4 D5 D6 D7
R
D0 D1 D2 D3 D4 D5 D6 D7
DATA
DATA
2 Extra clocks after last
transfer
Data Sheet