Fujitsu MB86R02 Jade-D Hardware Manual page 211

MB86R02 'Jade-D' Hardware Manual V1.64
Bit1-0: WDTH (data width)
These bits specify data bit width of the connected device.
0:
1:
2:
3:
*1: Initial value of data width to MEM_XCS[4]
MPX_MODE_1[1:0] = 2'b01 or 2'b10: 2:32 bit
Others:
11-4
8 bit (initial value)
16 bit
32 bit
Reserved
1:16 bit