sd_read_ext_reg
err = sd_read_ext_reg(card, fno, page, offset, 512, reg_buf);
err = sd_read_ext_reg(card, fno, page, offset, 512, reg_buf);
err = sd_read_ext_reg(card, 0, 0, 0, 512, gen_info_buf);
err = sd_read_ext_reg(card, fno, page, offset, 1, reg_buf);
err = sd_read_ext_reg(card, card->ext_power.fno, card->ext_power.page,