AX88780_07 ASIX [ASIX Electronics Corporation], AX88780_07 Datasheet - Page 15

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AX88780_07

Manufacturer Part Number
AX88780_07
Description
High-Performance Non-PCI Single-Chip 32-bit 10/100M Fast Ethernet Controller
Manufacturer
ASIX [ASIX Electronics Corporation]
Datasheet
3.9 16-bit Mode
RX and register access. For example, the driver requests a 16K bytes space from system and then sets the new window base
address to MEMBAS6 register. After that, driver should set bit 0 (DECODE_EN) of MEMBASE register to start decoding
for TX buffer, RX buffer and registers access. (Note: AX88780 H/W only decodes low 16-bit offset address.)
MEMBASE--Memory base Address
15:1
0
MEMBAS6--Memory base Address + 6
15:8
7:0
Note: The WINSIZE field of this address is used to define the MSB of new window base address, the TX buffer, RX buffer
and registers should be accessed through this new window base address in 16-bit mode. Please refer to below mapping
mechanism for details.
MEMBAS6 register. If AX88780 is allocated at the memory base address 0x20_0000 by hardware (i.e. the MEMBASE
register is allocated at 0x20_0000) and users would like to set the new window base address to 0x20_1000, the driver
should write 0x0010 to the MEMBAS6 register (offset 0x20_0006). In this case, the TX buffer area will be allocated from
0x20_1000 to 0x20_1EFF; the registers area will be allocated from 0x20_1F00 to 0x20_1FFF and the RX buffer area will
be allocated from 0x20_2000 to 0x20_2FFF.
Field
Field
AX88780 also supports 16-bit mode operation. AX88780 driver should request at least (8K + 8) bytes space for TX,
The following is an example to indicate how to define a new window base address in 16-bit mode by configuring the
DECODE_EN
WINSIZE
15
Name
Name
-
-
Set MEMBAS6 =
R/W
R/W
Type
RX buffer area
TX buffer area
Registers area
MEMBASE
(3840 bytes)
(4096 bytes)
R/W
R/W
(256 bytes)
Type
0x00
Default
-
0
Default
0x0010
Figure 5: 16-bit mode address mapping
-
Reserved. The output value is undefined if software read this field.
Window Base Pointer. (The MSB of new window base address)
This field defines another new windows base address for TX, RX and register
access. The total size is 8K bytes.
TX areas occupy 3840 bytes
Registers occupy 256 bytes.
RX areas occupy 4096 bytes.
Reserved. The output value is undefined if software read this field.
16-bit decode enable
Set to ‘1’ to start decoding.
15
0
Base address (xx_0000)
Base address + 6 (xx_0006)
Registers area (xx_1F00 ~ 1FFF)
RX buffer area (xx_2000 ~ 2FFF)
New window base address (xx_1000)
TX buffer area (xx_1000 ~ 1EFF)
Description
ASIX ELECTRONICS CORPORATION
Description
AX88780

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