Datasheet

W5500 Datasheet Version1.0.9 17 / 66
OM[1:0]
Meaning
00
Variable Data Length Mode, N-Bytes Data Phase (1 ≤ N)
01
Fixed Data Length Mode , 1 Byte Data Length (N = 1)
10
Fixed Data Length Mode , 2 Byte Data Length (N = 2)
11
Fixed Data Length Mode , 4 Byte Data Length (N = 4)
2.2.3 Data Phase
With the Control Phase set by the SPI Operation Mode Bits OM[1:0], the Data Phase
is set by two types of length, one type is the N-Bytes length (VDM mode) and the other
type is 1/2/4 Bytes (FDM mode).
At this time, 1 byte data is transferred through MOSI or MISO signal from MSB to LSB
sequentially.
2.3 Variable Length Data Mode (VDM)
In VDM mode, the SPI Frame Data Phase Length is determined by SCSn Control of the
External Host. That means that the Data Phase Length can have random value (Any
length from 1 Byte to N Bytes) according to the SCSn Control.
The OM[1:0] of the Control Phase should be ‘00’ value in VDM mode.