2. 上機(jī)實(shí)驗(yàn)

實(shí)驗(yàn)步驟：

• 先安裝 g_zero 驅(qū)動(dòng)程序：在開發(fā)板上執(zhí)行modprobe g_zero
• 然后連接 OTG 線到 PC
• 在 Ubuntu 中識別出設(shè)備
• 執(zhí)行測試程序
  • 先編譯：在 Ubuntu 里執(zhí)行如下命令

apt-cache search libusb               # 查找 libusb 開發(fā)包
sudo apt install libusb-1.0-0-dev     # 安裝 libusb 開發(fā)包
gcc -o zero_app zero_app.c -lusb-1.0  # 編譯

• 測試：在 Ubuntu 里執(zhí)行如下命令

$ sudo ./zero_app -l    # 列出設(shè)備的配置值
config 0: bConfigurationValue = 3
config 1: bConfigurationValue = 2

# 測試loopback功能
$ sudo ./zero_app -s 2                  # 選擇loopback的配置
$ sudo ./zero_app -wstr www.100ask.net  # 寫入字符串
current config: 2
in_ep = 0x81, out_ep = 0x1
$ sudo ./zero_app -rstr                # 讀出字符串
current config: 2
in_ep = 0x81, out_ep = 0x1
Read string: www.100ask.net

$ sudo ./zero_app -w 1 2 3 4 5 6 7 8   # 寫入8個(gè)字節(jié)
current config: 2
in_ep = 0x81, out_ep = 0x1
sudo ./zero_app -r                     # 讀到8個(gè)字節(jié)
current config: 2
in_ep = 0x81, out_ep = 0x1
transferred != in_ep_maxlen
Read datas:
01 02 03 04 05 06 07 08

#測試Source/Sink功能
$ sudo ./zero_app -s 3                   # 選擇source/sink的配置         
book@100ask:~/nfs_rootfs/05_libusb_zero$ sudo ./zero_app -r  # 讀數(shù)據(jù)
current config: 3
in_ep = 0x81, out_ep = 0x1
Read datas:
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

sudo ./zero_app -w 0 0 0  # 寫數(shù)據(jù), 只能寫入0, 
                          # 寫入其他值將會(huì)導(dǎo)致開發(fā)板上的驅(qū)動(dòng)認(rèn)為是錯(cuò)誤然后halt out端點(diǎn)
                          # 然后只能重新執(zhí)行 ”sudo ./zero_app -s 3“ 才能恢復(fù)