The partial_frm_wr_done is an optional output
port for frame buffer writes. It signals transition from 0 to 1 when the number of pixel
lines written into memory reaches the integer value set in the 0x0070 register. If the
register is reset, zero, or greater than the frame height, the 0‑to‑1 transition on the
output port asserts synchronously. By default, this occurs with the last pixel of the
frame.