PEB20570FV31XP Infineon Technologies, PEB20570FV31XP Datasheet - Page 132

• Manufacturer Part Number: PEB20570FV31XP
• Manufacturer: Infineon Technologies

Specifications of PEB20570FV31XP

• Lead Free Status / Rohs Status: Compliant

The DSP assigns each time slot used for transmitting an HDLC message to a different
address in the Receive/Transmit Input Buffers. The HDLCU decodes/encodes the time
slots into the corresponding addresses in the Receive/Transmit Output Buffers.
During every frame, two HDLCU activities are performed:
1. DSP access to the HDLCU
2. HDLCU encoding/decoding
At the beginning of a frame the DSP checks if the HDLCU is busy (HHOLD = ’0’).
Note: The DSP may only access the buffers and command RAM when DSPCTRL = ‘1’.
In the receive direction the DSP places HDLC message time slots to be processed from
the D-buffers into the Receive Input Buffer. Processed message time slot octets may be
read by the DSP from the Receive Output Buffer.
In the transmit direction the DSP places HDLC message time slots to be processed in
the Transmit Input Buffer. Processed time slots may be read from the Transmit Output
Buffer and placed into the D-Buffer of the IOMU, PCMU or TRANSIU from which they
will be transmitted during the next frame.
4.6.2
4.6.2.1
The DSP first resets the receive and transmit mechanisms of all HDLC channels.
1. The DSP requests the External Controller for HDLCU setup.
2. The DSP sets the bit DSPCTRL to ‘1’.
3. The DSP resets the receive mechanism and transmit mechanism of a channel by
4. The DSP sets DSPCTRL to ‘0’.
5. When the HDLCU finishes processing (HHOLD = ’1’), the HDLCU is initialized and is
4.6.2.2
The DSP must place a Start transmission command at the appropriate address in the
command RAM. If CRC encoding is required, the DSP must set bit 1 to ‘1’ in the
command vector. After the first flag has been transmitted, the HDLC starts to transmit
the message. In shared flag mode the HDLCU starts transmitting the message in the
frame adjacent to the reception of the Start transmission command.
Note: Messages with zero byte data content are not supported.
Data Sheet
setting the RECRES flag of its command vector to ‘1’ and inserting an abort command.
The DSP also writes the setup of the HDLCU.
ready for use.
HDLCU Operation
Initialization of the HDLCU
Transmitting a Message
115
Functional Description
PEB 20570
PEB 20571
2003-07-31