Please enable NBG0 and NBG1 only.

Use exactly the same data for the character pattern table (or bitmap pattern) and pattern name table of NBG0 and NBG1.

Please make NBG0 and NBG1 both shrinkable to 1/2 in the horizontal direction.

Set the same vertical screen scroll value for NBG0 and NBG1.
Set the horizontal screen scroll value of

NBG1 by 1 larger than the horizontal screen scroll value of NBG0.

Please set both horizontal increments of NBG0 and NBG1 to 2.

Color RAM mode should be mode 0.

Set the same priority number for NBG0 and NBG1.
Do not insert the

line color screen.

Please set the special priority of NBG0 and NBG1 to mode 0 for both.

Do not use the color calculation function.

Make the same setting for NBG0 and NBG1 for all other registers.