Adaptec 1737100 Programmer Manual - Page 37

Crcen, Caltcp

Page 37 highlights

Transmit Architecture Table 3-2. End Bit Functionality Desc. Type Conditions Functionality Frame (0,3,4) MinFrameDescSpacing !=0 The number of bytes between two consecutive frame descriptions is fixed. The queue wraps around at the end of the fixed address. No wrap in the middle of a frame descriptor. Frame (0,3,4) MinFrameDescSpacing =0 The number of bytes between two consecutive frame descriptions is variable. For type 0/4, the queue wraps after reading 16 bytes of descriptor data. For type 1/3, the queue wraps after reading 8 bytes of descriptors. Buffer (1,2) MinFrameDescSpacing must be 0. 'End' bit is valid only for the first descriptor of a frame. For type 1, the queue wraps after reading 8 bytes of descriptors data. For type 2, the queue wraps after reading 16 bytes of descriptor data. s INTR: Causes setting of the interrupt status bits (TxDmaDoneInt and/or TxFrameCompleteInt) after complete transmission of the entire packet. The appropriate interrupt status bit is set based on two control bits that the software programs at the initialization phase. Given 'INTR' is set the following table specifies the functionality: Table 3-3. Intr Bit Functionality DisableTxDmaCo TxCompletionDescAft mpletion erTxComplete Functionality 0 0 TxDmaDoneInt is set after complete DMA the whole packet. 0 1 TxDmaDoneInt is set after complete DMA the whole packet, and TxFrameCompleteInt is set after complete transmitting the whole frame. 1 0 None of the two interrupt status bits is set. 1 1 TxFrameCompleteInt is set after complete transmitting the whole frame. 'INTR' Note: The software driver may choose to work with another interrupt status bit, TxQueueDoneInt, that is not controlled by 'INTR'. The AIC-6915 sets this bit after the DMA-transfer of a completion descriptor for the last frame queued for transmit. The last frame is detected when the consumer and producer indices of the queue are equal. s CRCEN: Setting this bit enables the MAC to calculate and append the CRC value for the current packet. Clearing the bit disables the MACs ability to calculate the CRC value. s CALTCP: Setting this bit enables the F P to calculate TCP/UDP checksum for this packet. Clearing the bit disables the FPs ability to calculate the checksum. 3-7

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44
  • 45
  • 46
  • 47
  • 48
  • 49
  • 50
  • 51
  • 52
  • 53
  • 54
  • 55
  • 56
  • 57
  • 58
  • 59
  • 60
  • 61
  • 62
  • 63
  • 64
  • 65
  • 66
  • 67
  • 68
  • 69
  • 70
  • 71
  • 72
  • 73
  • 74
  • 75
  • 76
  • 77
  • 78
  • 79
  • 80
  • 81
  • 82
  • 83
  • 84
  • 85
  • 86
  • 87
  • 88
  • 89
  • 90
  • 91
  • 92
  • 93
  • 94
  • 95
  • 96
  • 97
  • 98
  • 99
  • 100
  • 101
  • 102
  • 103
  • 104
  • 105
  • 106
  • 107
  • 108
  • 109
  • 110
  • 111
  • 112
  • 113
  • 114
  • 115
  • 116
  • 117
  • 118
  • 119
  • 120
  • 121
  • 122
  • 123
  • 124
  • 125
  • 126
  • 127
  • 128
  • 129
  • 130
  • 131
  • 132
  • 133
  • 134
  • 135
  • 136
  • 137
  • 138
  • 139
  • 140
  • 141
  • 142
  • 143
  • 144
  • 145
  • 146
  • 147
  • 148
  • 149
  • 150
  • 151
  • 152
  • 153
  • 154
  • 155
  • 156
  • 157
  • 158
  • 159
  • 160
  • 161
  • 162
  • 163
  • 164
  • 165
  • 166
  • 167
  • 168
  • 169
  • 170
  • 171
  • 172
  • 173
  • 174
  • 175
  • 176
  • 177
  • 178
  • 179
  • 180
  • 181
  • 182
  • 183
  • 184
  • 185
  • 186
  • 187
  • 188
  • 189
  • 190

3-7
Transmit Architecture
INTR
: Causes setting of the interrupt status bits (TxDmaDoneInt and/or
TxFrameCompleteInt) after complete transmission of the entire packet. The
appropriate interrupt status bit is set based on two control bits that the software
programs at the initialization phase. Given ‘
INTR
’ is set the following table specifies
the functionality:
Note:
The software driver may choose to work with another interrupt status bit,
TxQueueDoneInt, that is not controlled by ‘
INTR
’. The AIC-6915 sets this bit after
the DMA-transfer of a completion descriptor for the last frame queued for
transmit. The last frame is detected when the consumer and producer indices of
the queue are equal.
CRCEN
: Setting this bit enables the MAC to calculate and append the CRC value for
the current packet. Clearing the bit disables the MACs ability to calculate the CRC
value.
CALTCP
: Setting this bit enables the F P to calculate TCP/UDP checksum for this
packet. Clearing the bit disables the FPs ability to calculate the checksum.
Table 3-2. End Bit Functionality
Desc. Type
Conditions
Functionality
Frame (0,3,4)
MinFrameDescSpacing
!=0
The number of bytes between two
consecutive frame descriptions is fixed. The
queue wraps around at the end of the fixed
address. No wrap in the middle of a frame
descriptor.
Frame (0,3,4)
MinFrameDescSpacing
=0
The number of bytes between two
consecutive frame descriptions is variable.
For type 0/4, the queue wraps after reading
16 bytes of descriptor data. For type 1/3, the
queue wraps after reading 8 bytes of
descriptors.
Buffer (1,2)
MinFrameDescSpacing
must be 0.
‘End’ bit is valid only
for the first descriptor
of a frame.
For type 1, the queue wraps after reading 8
bytes of descriptors data.
For type 2, the queue wraps after reading 16
bytes of descriptor data.
Table 3-3. Intr Bit Functionality
DisableTxDmaCo
mpletion
TxCompletionDescAft
erTxComplete
Functionality
0
0
TxDmaDoneInt is set after complete DMA the
whole packet.
0
1
TxDmaDoneInt is set after complete DMA the
whole packet, and TxFrameCompleteInt is set
after complete transmitting the whole frame.
1
0
None of the two interrupt status bits is set.
1
1
TxFrameCompleteInt is set after complete
transmitting the whole frame. ‘INTR’