Interlacing

The SNES supports interlacing. It is available only in Mode 5 and Mode 6. ^[3] It is enabled by setting bit 0 of SETINI.

In interlacing on the SNES, the first field is called "odd" and the second field is called "even."

For even fields, the electron beam begins scanning at the top-middle of the screen instead of the top-left like in odd fields. For odd fields, it finishes scanning at the middle-bottom instead of the bottom-right like in even fields. ^[2]

References

1. Official Super Nintendo development manual on interlacing: page 2-18-1 of Book I
2. page 2-1-2 of Book I, lbid
3. https://nesdoug.com/2022/05/30/other-modes