Operating Precautions for VR4133 TM
No. 7 | Disconnect at the end of PCI burst cycle |
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| (Specification change notice) |
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| Details |
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| The last transfer of a PCI burst cycle is regarded as a disconnect cycle by VR4133, if STOP# and | ||||||||
| TRDY# are both asserted during the | ||||||||
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| unnecessary |
| PCLK |
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| cycle |
| AD | A+0 | D0 | D1 | A+8 | D2 | D3 | A+12 | D3 |
| FRAME# |
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IRDY#
TRDY#
STOP#
D0 ,D1,D2 are burst data; D3 is last burst data and D2 is
Therefore one of the following workarounds must be implemented:
(1)Do not use
(2)Do not use LD and SD instructions and do not locate PCI memory and I/O areas in cached memory region of the CPU, so that burst cycles as shown above are not generated.
No. 8 | Ethernet: receive short packet |
| (Documentation errata) |
| Details |
| The packet size of VLAN is designed for minimum 68 bytes length, but this is not described in |
| user’s manual. |
| If a VLAN packet is received with a length of |
| judged it as a short packet, and a packet will be discarded. |
| Using a packet with a length of less than 68 bytes can be realized by the following method: |
| Set a ‘special value’ into VLTP (15:0) of VLTP0/1 (0x0f001464 / 0x0f001764) register. The |
| ‘special value' has not to be a VLAN type, which you want to receive. The data can be received |
| as a usual packet, and judged as a VLAN packet by software. In this case, following items are |
| different from usual VLAN procedure. |
(1)All the VLAN packets recognized by the TYPE field of receiving descriptor status are described as normal packets.
(2)The statistics counter R64C0/1, R127C0/1, R255C0/1, R511C0/1, R1KC 0/1 and RMAXC0/1 count normal packets.
Customer Notification | 7 |