REG_VDP_CTRL
reg = io_read(sd, REG_VDP_CTRL);
io_write(sd, REG_VDP_CTRL, reg);
io_write(sd, REG_VDP_CTRL, 0x1f);
reg = io_read(sd, REG_VDP_CTRL);
io_write(sd, REG_VDP_CTRL, reg);
reg = io_read(sd, REG_VDP_CTRL);
io_write(sd, REG_VDP_CTRL, reg);
reg = io_read(sd, REG_VDP_CTRL);
io_write(sd, REG_VDP_CTRL, reg);