AM79C90 Advanced Micro Devices, AM79C90 Datasheet - Page 61

• Manufacturer Part Number: AM79C90
• Description: CMOS Local Area Network Controller for Ethernet (C-LANCE)
• Manufacturer: Advanced Micro Devices

17. Elimination of Burn-In Option
The burn-in option for the C-LANCE is no longer avail-
able. Thus, the ordering part number Am79C90PCB is
no longer valid (see page 4 of the C-LANCE data
sheet).
18. RX Descriptor Zero Buffer Byte Count Handling
The 12-bit BCNT field in the receive descriptor of the
LANCE and C-LANCE devices is loaded with the 2’s
complement of the number of bytes allocated to the
Am79C90
associated receive buffer. In the LANCE device, when
all 0’s are written to the BCNT field in a receive descrip-
tor, a buffer length of 4096 (2
the C-LANCE device, the case of all 0’s in the receive
descriptor may produce unpredictable results.
This difference should not cause problems in IEEE
802.3-compliant networks, because 802.3 has a maxi-
mum packet length specification of 1518 bytes.
12
) bytes is assumed. In
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