IOM2 CONTROLLER
S3C2500B
9-2
9.3 IOM2 BUS
The IOM2 bus provides a symmetrical full-duplex communication link, containing user data,
control/programming, and status channels. Both the line card and terminal portions of the IOM2 standard utilize
the same basic frame and clocking structure, but differ in the number and usage of the individual channels. The
various channels are time-multiplexed over a four-wire serial interface. Data is clocked by a Data Rate
Clock(DCL) that operates at twice the data rate. Frames are delimited by an 8-kHz Frame Synchronization
Clock(FSC). Data is carried over Data Upstream(DU) and Data Downstream(DD) signals. Three additional
signals are specified in the terminal mode to facilitate connecting components that do not directly support IOM2.
These are a 1x-Bit rate Clock (BCL), and two Serial Data Strobes that identify the location of the B channels
(SDS1 and SDS2). The S3C2500B includes two optional signals, BCL and SDS1. SDS1 is called STRB in
S3C2500B. In S3C2500B, the terminal mode operation is supported but line-card mode is not supported.
Figure9-1 shows the IOM2 channel structure in terminal mode.
B1
B2
D CI0
IC1
IC2
MON0
CI1
MON1
B1
B2
D CI0
IC1
IC2
MON0
CI1
MON1
BAC TAD
S/G A/B
MX
MR
MX
MR
MX
MR
MX
MR
FSC
DU
DD
STRB
DCL
BCL
Figure 9-1. IOM2 Channel Structure in Terminal
DU, DD
768 kbit/s (DU = data upstream = output, DD = data downstream = input)
DCL
1536 kHz input (Double Data Rate)
FSC
8 kHz input
BCL
768 kHz output
STRB
strobe signal for non-IOM2 device
Summary of Contents for S3C2500B
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Page 80: ...PRODUCT OVERVIEW S3C2500B 1 46 NOTES ...
Page 296: ...MEMORY CONTROLLER S3C2500B 5 60 NOTES ...
Page 531: ...GDMA CONTROLLER S3C2500B 12 24 NOTES ...
Page 593: ...I O PORTS S3C2500B 15 12 NOTES ...