如何用命令查找函数类型定义

我的串口连上min2440后，可以在miniocom中看到supervivi返回的菜单，如下：

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##### FriendlyARM BIOS 2.0 for 2440 #####
[x] format NAND FLASH for Linux
[v] Download vivi
[k] Download linux kernel
[y] Download root_yaffs image
[a] Absolute User Application
[n] Download Nboot for WinCE
[l] Download WinCE boot-logo
[w] Download WinCE NK.bin
[d] Download & Run
[z] Download zImage into RAM
[g] Boot linux from RAM
[f] Format the nand flash
[b] Boot the system
[s] Set the boot parameters
[u] Backup NAND Flash to HOST through USB(upload)
[r] Restore NAND Flash from HOST through USB
[q] Goto shell of vivi
[i] Version: 1026-2K
Enter your selection:

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但是，我操作不了，我按了“ f "，然后按 enter，画面根本没有反应，请问这是什么问题呢？ 大家帮帮忙！

这是个啥设备？

俺自己来记录一下自己解决方法，minicom -s -> Serial port setup ->
照如下设置：
+-----------------------------------------------------------------------+
| A - Serial Device : /dev/ttyS0 |
| B - Lockfile Location : /var/lock |
| C - Callin Program : |
| D - Callout Program : |
| E - Bps/Par/Bits : 115200 8N1 |
| F - Hardware Flow Control : No |
| G - Software Flow Control : No |
| |
| Change which setting? |
+-----------------------------------------------------------------------+