peb3456e Infineon Technologies Corporation, peb3456e Datasheet - Page 69

• Manufacturer Part Number: peb3456e
• Description: Channelized T3 Termination, With Ds3 Framer, M13 Multiplexer, T1/e1 Framers And 256-channel Hdlc/ppp Controller
• Manufacturer: Infineon Technologies Corporation

TransmitDataPointer
CEN
C
4.3.5
The data management unit transmit provides the interface between system memory on
one side and the internal transmit buffer on the other side. The data management unit
handles requests of the transmit buffer, controls the address and burst length
calculation, initiates data transfers from system memory to the transmit buffer and
handles the linked lists on a per channel basis.
For initialization the CPU programs the first transmit descriptor address, the interrupt
mask, the interrupt queue and starts the channel with the ’Transmit Init’ command. For
detailed description of channel commands refer to
Page
them in its on-chip channel database.
The first transmit descriptor is fetched from system memory and stored in the chip
internal channel database the first time the transmit buffer requests data for a channel.
It contains a pointer to the data buffer, the length of the data section as well as a pointer
to the next transmit descriptor. After the first descriptor is stored internally a ’Transmit
Command Complete’ interrupt vector is generated.
Data transfers are requested as long as the number of empty locations is below a
programmable refill threshold. The number of empty locations is reported from the
transmit buffer to the data management unit. Task of the data management unit is to
calculate the number of bytes that can be loaded from the data section based on the NO
Data Sheet
164.The data management unit then fetches the given information and stores
Data Management Unit Transmit
•completed reading a data section normally, or
•it was aborted by a ’Transmit Off’ command or by a ’Transmit Abort/
This 32-bit pointer contains the start address of the transmit data section.
Although the data management unit works DWORD oriented, it is
possible to begin transmit data section at byte addresses.
Complete Enable
This bit is set by the CPU if the complete bit mechanism is desired:
0
1
Complete
This bit is set by the data management unit, when the bit CEN of a
descriptor is set and when it
The complete bit releases the descriptor.
Branch’ command.
The data management unit will NOT update the transmit
descriptor with the C bit. In this mode the use of the THI interrupt
is recommended.
The data management unit will set the C bit.
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“Channel Commands” on
Functional Description
PEB 3456 E
05.2001