nanopc_T2  GPIO 的Pin11 Pin12变成TTL的读写

nanopc_T2   烧写的是ubuntu的qt界面系统，用ttl转232连接调试口（ttyAMA0）可以连接上，但使用ttyAMA2和ttyAMA3就连接不上，通过信息查看ttyAMA1被其他设备占用，而ttyAMA2和ttyAMA3驱动正常，也没有被占用，但不可使用，如何才能使用ttyAMA2和ttyAMA3转出TTL电平，希望给予解答，谢谢

dmesp

[    0.000000] Kernel command line: console=ttyAMA0,115200n8 root=/dev/mmcblk0p2 rootfstype=ext4 rootwait init=/sbin/init systemd.show_status=false g_ether.host_addr=82:cf:ce:fa:44:18 console=tty1 lcd=S70,128dpi bootdev=2

[    0.196000] uart-pl011.0: ttyAMA0 at MMIO 0xc00a1000 (irq = 7) is a PL011 rev3
[    0.200000] console [ttyAMA0] enabled
[    0.204000] uart-pl011.1: ttyAMA1 at MMIO 0xc00a0000 (irq = 6) is a PL011 rev3
[    0.208000] uart-pl011.3: ttyAMA2 at MMIO 0xc00a3000 (irq = 9) is a PL011 rev3
[    0.212000] uart-pl011.4: ttyAMA3 at MMIO 0xc006d000 (irq = 10) is a PL011 rev3

[    0.852000] uart-pl011 uart-pl011.0: no DMA platform data
[    0.860000] uart-pl011 uart-pl011.1: no DMA platform data
[    0.868000] uart-pl011 uart-pl011.3: no DMA platform data
[    0.876000] uart-pl011 uart-pl011.4: no DMA platform data

cat /proc/tty/driver/ttyAMA

serinfo:1.0 driver revision:
0: uart:PL011 rev3 mmio:0xC00A1000 irq:7 tx:58 rx:0 RTS|DTR
1: uart:PL011 rev3 mmio:0xC00A0000 irq:6 tx:39277 rx:2096 RTS|CTS|DTR|DSR|CD
2: uart:PL011 rev3 mmio:0xC00A3000 irq:9 tx:0 rx:0
3: uart:PL011 rev3 mmio:0xC006D000 irq:10 tx:0 rx:0