Eeprom Memory - Avaya Nortel Communication Server 1000 Reference

NTBK51 Downloadable D-channel Handler daughterboard

EEPROM memory

The DDCH uses a 1024 bit serial EEPROM for storing the Nortel product code and a revision
level. This information can be queried by the software.
Serial communication controller
The serial controller is the Zilog Z16C35 and is referenced as the Integrated Controller (ISCC).
The ISCC includes a flexible Bus Interface Unit (BIU) and four Direct Memory Access (DMA)
channels, one for each receive and transmit. The DMA core of the ISCC controls the data
transfer between local RAM and the communication ports.
Sanity timer
A sanity timer is incorporated on the DDCH to prevent the MPU from getting tied-up as the
result of a hardware or software fault. If the MPU encounters a hardware or software fault and
enters a continuous loop, the sanity timer enables the DDCH to reset itself.
Bus timer
The bus timer presents an error signal to the MPU if an attempt to access a device did not
receive acknowledgment within the bus time-out period of 120 ms.
Download operation
Downloading is performed in either of two modes: background mode or maintenance mode.
Before a download takes place, a D-channel link must be configured. The following situations
lead to software downloading:
• during initialization when new software is installed
• when enabling the card or application
• during card reset (due to loss of software or corruption)
• during a background audit
564 Circuit Card Reference
Comments? infodev@avaya.com
July 2011