mpc52xx_psc_buffer_8
out_8(&psc->mpc52xx_psc_buffer_8, tx_buf[sb]);
out_8(&psc->mpc52xx_psc_buffer_8, 0);
rx_buf[rb] = in_8(&psc->mpc52xx_psc_buffer_8);
in_8(&psc->mpc52xx_psc_buffer_8);
out_8(&PSC(port)->mpc52xx_psc_buffer_8, c);
return in_8(&PSC(port)->mpc52xx_psc_buffer_8);