pef20320 Infineon Technologies Corporation, pef20320 Datasheet - Page 193

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

PEB 20320
Application Notes
Programming the MUNICH32 for this Application
The basic programming of the MUNICH32 for this application is realized in the Module
Initialization Routine. Further programming is done by calling the function ‘Init Channel’
for each channel once. Transmit data is then added to the memory structures by passing
a message with linked transmit descriptor(s) to the function ‘Send Frame’.
Module Initialization Routine
Here the IM-bit is cleared because the MUNICH32 DDM expects the action request
acknowledge interrupt. The values for PCM and MFL are set. The PCM format is a 32-
channel format according to CEPT. The maximum frame length is set to its maximum.
Finally the address and length of a new interrupt queue are defined. Those values will
not be changed anymore.
Init Channel Routine
The function ‘Init Channel’ initializes the time-slot assignment and the channel
specification for one channel. The channel number is set to the value of the variable
‘channel’. The MUNICH32 is alerted to access all time-slot assignments and the channel
specification by setting the in-bit.
The fillmask (transmit and receive) for the selected channel is written in the appropriate
word of the time-slot assignment. All other channels and their fillmasks are not affected.
For this application all interrupts are enabled. Initialization of the selected channel
comprises the definition of a new ITBS value and initialization of the receiver and the
transmitter. The transmit hold bit is cleared. After initialization the MUNICH32 starts
polling the hold bit of the current transmit descriptor. Therefore a transmit descriptor is
allocated and connected to the memory structures. Its hold bit and fe-bit are set to one,
its no-bits are set to zero. For that reason the MUNICH32 does not transmit anything but
polls this descriptor. Since after the receiver’s initialization the MUNICH32 is ready to
receive data, a queue of receive descriptors is allocated and linked to the memory
structures. The hold bit of the last descriptor in the list is set to indicate the end of the list.
In all other descriptors the hold bit is cleared.
User’s Manual
193
01.2000