DS21455 Maxim Integrated Products, DS21455 Datasheet - Page 202

• Manufacturer Part Number: DS21455
• Description: Network Controller & Processor ICs Quad E1-T1-J1 Single -Chip Transceiver (S
• Manufacturer: Maxim Integrated Products

Specifications of DS21455

• Product: Framer
• Number Of Transceivers: 4
• Data Rate: 64 Kbps
• Supply Voltage (max): 3.465 V
• Supply Voltage (min): 3.135 V
• Supply Current (max): 328 mA
• Maximum Operating Temperature: + 70 C
• Minimum Operating Temperature: 0 C
• Mounting Style: SMD/SMT
• Package / Case: BGA

DS21455/DS21458 Quad T1/E1/J1 Transceivers
30. EXTENDED SYSTEM INFORMATION BUS (ESIB)
The ESIB function is carried forward from the previous generation of single port transceiver devices such
as the DS2155 and DS2156. This function allows the host to read interrupt and alarm status of multiple
ports, up to 8, with a single read of any one of the devices in the ESIB group. Each device is programmed
to drive a single bit on the CPU bus (leaving the other bits in high-Z) when one of the four ESIB registers
(ESIB1–ESIB4) is accessed on any device in the group. Three signals were used to allow the separate
devices to communicate with each other in order to respond to an ESIB register access on any device in
the group. These signals are ESIBS0, ESIBS1, and ESIBRD. Since the DS21458 and DS21455 are quad
monolithic devices, the ESIB function can be used to arrange two devices (eight transceivers) in an ESIB
group. Primarily, this is used to quickly sort out interrupts since the host can determine which port or
ports are causing and interrupt with a single CPU read cycle. The user can also read various alarm
indicators on all members. There are two control registers, ESIBCR1 and ESIBCR2, and four information
registers, ESIB1, ESIB2, ESIB3, and ESIB4, in each transceiver. Reading register ESIB1 of any member
of the group, the host can read the interrupt status on all members. Via ESIB2 the host can gather
synchronization status on all members of the group. ESIB3 and ESIB4 can be programmed to report
various alarms on a device-by-device basis.
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