pef20320 Infineon Technologies Corporation, pef20320 Datasheet - Page 223

• Manufacturer Part Number: pef20320
• Description: Multichannel Network Interface Controller For Hdlc With 32 Channels
• Manufacturer: Infineon Technologies Corporation

6.2
Implementation independent:
– Start Address
– Control & Configuration Section 908 byte
– Tx Descriptor Size
– Rc Descriptor Size
Implementation dependent:
– Interrupt Queue Size
– Data Buffer Size
– Allocation of Tx and Rc descriptors per channel
Example:
The MUNICH32 is used in a 31 channel ISDN Primary Access application, that means
that 31 full duplex channels are active. The LAPD protocol is implemented. In this case
a window size of 7 is specified, that means that 7 Rc Descriptors and in transmit direction
7 Tx Descriptors must be available for each channel. The Data Buffer Size is set to 260
byte according to the LAPD specification.
Summary:
In our example a memory space of 120 kbytes is required.
User’s Manual
In general the memory space requirement may be calculated the following way:
+ Size of Control & Configuration Section
+ Interrupt Queue Size
+ number of channels
number of channels
–––––––––––––––––––––––––––––––––––––––––––––
= Total MUNICH32 Memory Space Requirement
– 31 channels;
– Interrupt Queue Size = 1024 byte;
– 7 Tx and 7 Rc Descriptors;
– Data Buffer Size = 260 byte;
Start Address
MUNICH32 Memory Space Requirement
[number of Rc Descriptors
[number of Tx Descriptors
64 byte < Interrupt Queue Size < 16384 byte
Data Buffer Size
12 byte
16 byte
4 byte
223
(Rc Descriptor Size + Data Buffer Size)]
(Tx Descriptor Size + Data Buffer Size)] +
Application Hints
PEB 20320
01.2000