NEC UPD98413 User Manual page 68

(f) Error processing and transmission of an abort packet
This section shows the processing of µ PD98413 when the following errors occur in the transmit side.
• Transmission FIFO overflow
• Transmission FIFO underflow
• The next start-of-packet notification is received before an end-of-packet notification
• The TERR signal is asserted
Upon detecting any of the following errors, the µ PD98413 sends a POS packet as an abort packet. 7Dh and 7Eh
are inserted at the end of the packet as the abort packet.
• Transmission FIFO underflow
• The TERR signal is asserted
Address Control
Transmission FIFO overflow
If a transmission FIFO overflow occurs during packet transmission (the transmission FIFO overflows before
TEOP is asserted), the µ PD98413 sends all the data that remains in the transmission FIFO at that point. The
µ PD98413 also indicates the error and interrupt when a transmission FIFO overflow occurs.
If, after a transmission FIFO overflow occurs, the remaining data for that packet is entered (the data is entered
without TSOP being asserted), the µ PD98413 discards that data.
Transmission FIFO underflow
If a transmission FIFO underflow occurs during packet transmission (the transmission FIFO becomes empty
before TEOP is asserted), the µ PD98413 inserts 7Dh and 7Eh after the data sent before the underflow occurs,
and sends the data as an abort packet.
transmission FIFO underflow occurs.
If, after a transmission FIFO underflow occurs, the remaining data for that packet is entered (the data is entered
without TSOP being asserted), the µ PD98413 discards that data.
The next start-of-packet notification is received before an end-of-packet notification (EOP error)
If the next start-of-packet notification is received before an end-of-packet notification during packet transmission
(the TSOP of the next packet is asserted before TEOP is asserted), the µ PD98413 indicates the error and
interrupt.
TERR signal is asserted
If the TERR signal is asserted during packet transmission, the µ PD98413 inserts 7Dh and 7Eh and sends the
data as an abort packet.
68
CHAPTER 3 FUNCTIONAL OUTLINE
Figure 3-23. Abort Packet
Information
The µ PD98413 also indicates the error and interrupt when a
PRELIMINARY
7Dh 7Eh
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