W5300 datasheet(24/128 Pages) WIZNET

24 / 128 page

2. System Memory Map

According to the host interface, W5300 supports direct address mode and indirect address

mode.

The direct address mode is that the target host system can directly access W5300 registers

after mapping the registers to T.M.S(Target host system Memory-mapped I/O Space).

Direct address mode memory map is composed of Mode register(MR), COMMON registers, and

SOCKET registers. Those registers are mapped in T.M.S sequentially increasing by 2bytes from

the BA(Base Address) of T.M.S. Using the mapping address, the target host system can directly

access MR, COMMON registers and SOCKET registers. To use the direct address mode, total

0x400 bytes are required for memory space.

In indirect address mode, target host system indirectly accesses COMMON registers and

SOCKET registers by using IDM_AR(Indirect Mode Address Register) and IDM_DR(Indirect

Mode Data Register) which are just only directly mapped in T.M.S together with MR.

Indirect address mode memory map is composed of direct accessible MR, IDM_AR, IDM_DR

and indirect accessible COMMON & SOCKET registers. Only MR, IDM_AR and IDM_DR are

mapped in T.M.S sequentially increasing by 2Bytes from BA of T.M.S, but COMMON & SOCKET

registers are not mapped in T.M.S because those register can be accessed indirectly using

IDM_AR & IDM_DR. To use the indirect address mode, just 0x06 bytes are required for memory

space.

When target host system access Interrupt register(IR) of COMMON registers at the indirect

address mode, it is processed as below:

Host Write : Set IDM_AR to 0x0002, IR address

(IDM_AR = 0x0002)

Set IDM_DR to 0xFFFF

(IDM_DR = 0xFFFF)

Host Read : Set IDM_AR to 0x0002, IR address

(IDM_AR = 0x0002)

Read IDM_DR and save as Value

(Value = IDM_DR)

The host interface mode of W5300 is decided according to the value of ‘IND’ bit (0th bit) of MR.

MR(0)

= ‘0’ => Direct address mode

MR(0)

= ‘1’ => Indirect address mode

The memory map of each address mode is as below:

W5300 Datasheet(PDF) 24 Page - WIZnet Co., Ltd