ds21ft40 Maxim Integrated Products, Inc., ds21ft40 Datasheet - Page 65

• Manufacturer Part Number: ds21ft40
• Description: Ds21ft40 Four X Three 12 Channel E1 Framer
• Manufacturer: Maxim Integrated Products, Inc.

For all bus configurations, one framer will be configured as the master device and the remaining framers
on the shared bus will be configured as slave devices. Refer to the IBO register description below for
more detail. In the 4.096 MHz bus configuration there is one master and one slave per bus. Figure 15-1
shows the DS21Q44 configured to support two 4.096 MHz buses. Bus 1 consists of framers 0 and 1. Bus
2 consists of framers 2 and 3. Framers 0 and 2 are programmed as master devices. Framers 1 and 3 are
programmed as slave devices. In the 8.192 MHz bus configuration there is one master and three slaves.
Figure 15-2 shows the DS21Q44 configured to support a 8.192 MHz bus. Framer 0 is programmed as the
master device. Framers 1, 2 and 3 are programmed as slave devices. Consult timing diagrams in section
16 for additional information.
When using the frame interleave mode, all framers that share an interleaved bus must have receive signals
(RPOS & RNEG) that are synchronous with each other. The received signals must originate from the
same clock reference. This restriction does not apply in the byte interleave mode.
IBO: INTERLEAVE BUS OPERATION REGISTER (Address = B5 Hex)
Master Device Bus Select Table 15-1
(MSB)
SYMBOLS
–
INTSEL
MSEL0
MSEL1
MSEL1
IBOEN
–
–
–
–
0
0
1
1
–
POSITION
MSEL0
IBO.7
IBO.6
IBO.5
IBO.4
IBO.3
IBO.2
IBO.1
IBO.0
0
1
0
1
–
NAME AND DESCRIPTION
Master Device Bus Select Bit 0 See table 15-1.
Master Device Bus Select Bit 1 See table 15-1.
Not Assigned. Should be set to 0.
Not Assigned. Should be set to 0.
Not Assigned. Should be set to 0.
Not Assigned. Should be set to 0.
Interleave Bus Operation Enable
0 = Interleave Bus Operation disabled.
1 = Interleave Bus Operation enabled.
Interleave Type Select
0 = Byte interleave.
1 = Frame interleave.
Slave device.
Master device with 1 slave device (4.096 MHz bus rate)
Master device with 3 slave devices (8.192 MHz bus rate)
Reserved
–
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IBOEN
Function
INTSEL
MSEL0
MSEL1
(LSB)
DS21FT40