A structure defining a single Ethernet DMA buffer descriptor.
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#include <emac.h>
A structure defining a single Ethernet DMA buffer descriptor.
Definition at line 142 of file emac.h.
The fourth descriptor word contains either a pointer to the next descriptor in the ring or a pointer to a second data buffer. The meaning of the word is controlled by the ``CHAINED'' control bit which appears in the first word of the transmit descriptor or the second word of the receive descriptor.
Definition at line 175 of file emac.h.
| void* tEMACDMADescriptor::pvBuffer1 |
The third descriptor word contains a pointer to the buffer containing data to transmit or into which received data should be written. This pointer must refer to a buffer in internal SRAM. Pointers to flash or EPI-connected memory may not be used and will result in the MAC reporting a bus error.
Definition at line 166 of file emac.h.
| volatile uint32_t tEMACDMADescriptor::ui32Count |
The second descriptor word contains information on the size of the buffer or buffers attached to the descriptor and various additional control bits.
Definition at line 157 of file emac.h.
| volatile uint32_t tEMACDMADescriptor::ui32CtrlStatus |
The first DMA descriptor word contains various control and status bits depending upon whether the descriptor is in the transmit or receive queue. Bit 31 is always the ``OWN'' bit which, when set, indicates that the hardware has control of the descriptor.
Definition at line 150 of file emac.h.
| volatile uint32_t tEMACDMADescriptor::ui32ExtRxStatus |
The fifth descriptor word is reserved for transmit descriptors but used to report extended status in a receive descriptor.
Definition at line 181 of file emac.h.
| volatile uint32_t tEMACDMADescriptor::ui32IEEE1588TimeHi |
The eighth descriptor word contains the high 32 bits of the 64-bit timestamp captured for transmitted or received data.
Definition at line 202 of file emac.h.
| volatile uint32_t tEMACDMADescriptor::ui32IEEE1588TimeLo |
The seventh descriptor word contains the low 32 bits of the 64-bit timestamp captured for transmitted or received data. The value is set only when the transmitted or received data contains the end of a packet. Availability of the timestamp is indicated via a status bit in the first descriptor word.
Definition at line 196 of file emac.h.
| uint32_t tEMACDMADescriptor::ui32Reserved |
The sixth descriptor word is reserved for both transmit and receive descriptors.
Definition at line 187 of file emac.h.
The documentation for this struct was generated from the following file:
1.8.9.1 
