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| Figure 7. Transmit Buffer Descriptor Format | ||||
Word 0 |
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31 |
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| 0 |
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| Next Descriptor Pointer |
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Word 1 |
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31 |
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| 0 |
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| Buffer Pointer |
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Word 2 |
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31 |
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| 16 | 15 | 0 | |
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| Buffer Offset |
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| Buffer Length | |
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Word 3 |
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31 | 30 | 29 | 28 | 27 | 26 |
| 25 | 16 |
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SOP | EOP | OWNER | EOQ | TDOWNCMPLT | PASSCRC |
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| Reserved |
15 |
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| 0 |
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| Packet Length |
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Example 1. Transmit Buffer Descriptor in C Structure Format
/*
//EMAC Descriptor
//The following is the format of a single buffer descriptor
//on the EMAC.
*/ |
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typedef | struct _EMAC_Desc { |
struct | _EMAC_Desc *pNext; /* Pointer to next descriptor in chain */ |
Uint8 *pBuffer; /* Pointer to data buffer */ | |
Uint32 | BufOffLen; /* Buffer Offset(MSW) and Length(LSW) */ |
Uint32 | PktFlgLen; /* Packet Flags(MSW) and Length(LSW) */ |
} EMAC_Desc; | |
/* Packet Flags */ | |
#define | EMAC_DSC_FLAG_SOP 0x80000000u |
#define | EMAC_DSC_FLAG_EOP 0x40000000u |
#define | EMAC_DSC_FLAG_OWNER 0x20000000u |
#define | EMAC_DSC_FLAG_EOQ 0x10000000u |
#define | EMAC_DSC_FLAG_TDOWNCMPLT 0x08000000u |
#define | EMAC_DSC_FLAG_PASSCRC 0x04000000u |
22 | EMAC/MDIO Module | SPRUFL5B |
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