Adapter Internal Registers
A-36

A.3.13 Burst Size Register –BSIZEreg @ 0x44 (DIO) (Byte 1)

This register is used to set the receive and transmit burst sizes to be used by

the adapter. This register is only writable while the ThunderLAN controller is

in reset. (NRESET = 0). This register is set to 0x22 on an Ad_Rst or when

PRST# is asserted.

89101112131415
Rx Burst SizeTx Burst Size
Byte 1
Table A–17. Burst Size Register Bits
Bit Name Function
15–12 Tx burst size Transmit burst size: This nibble code indicates the burst size to be used in data transfers
for transmit operations (Tx list or data transfers). The code indicates the maximum num-
ber of bytes to be transferred in any one transmit DMA data burst. At reset, the burst
size is set to a default level of 64 bytes (code = 2).
The burst size codes are:
0: 16 bytes
1: 32 bytes
2: 64 bytes (default)
3: 128 bytes
4: 256 bytes
5– 7: 512 bytes
8– F: reserved
11–8 Rx burst size Receive burst size: This nibble code indicates the burst size to be used in data transfers
for receive operations (Rx list or data transfers). The code indicates the maximum num-
ber of bytes to be transferred in any one receive DMA data burst. At reset, the burst size
is set to a default level of 64 bytes (code = 2).
The burst size codes are:
0: 16 bytes
1: 32 bytes
2: 64 bytes (default)
3: 128 bytes
4: 256 bytes
5– 7: 512 bytes
8– F: reserved