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本帖最后由 zhcj66 于 2013-8-23 11:38 编辑
因为公司最近用到了Android平板连接STM32F103，由于向我这样没有研究过USB协议的 简直是个晴天霹雳，在偶然的一次发现网上有Android的USB转串口的芯片，于是就顺藤摸瓜找到了FTDI公司。回馈阿莫论坛，希望阿莫能给穿上裤子哦！
当时FTDI公司刚刚推出FT311D 我买了几个样片，还没怎么测试 ，FTDI公司说我买的几片样片还有BUG 。因为这颗芯片是刚刚推出的 难免有BUG 好在FTDI反应比较快，到现在芯片已经成熟了。
废话少说 先说一下我用的FTDI的FT311D
FT311D可以实现的功能如下
1.Android的USB转 串口
2.Android的USB转 IIC
3.Android的USB转 SPI
4.Android的USB转 GPIO
The FT311D is a Full Speed USB host
specifically targeted at providing
access to peripheral hardware from an
Android platform with a USB device
port. The device will bridge the USB
port to six user selectable interface
types and has the following advanced
features:
Single chip USB to selectable interface.
Entire USB protocol handled on the chip. No
USB specific firmware programming required.
Interface options selectable via 3 mode select
pins.
7 GPIO lines interface option
Basic UART interface with RXD, TXD, RTS, CTS
pins option.
TX_ACTIVE signal for controlling transceivers
on RS485 interfaces.
4 PWM channels option.
I2C master interface option.
SPI Slave interface option supporting modes 0,
1, 2 and 3 with MSB/LSB options
SPI Master interface option supporting modes
0, 1, 2 and 3 with MSB/LSB options.
USB error indicator pin
Suitable for use on any Android platform
supporting Android Open Accessory Mode
(Typically 3.1 onwards, however some
platforms may port Open Accessory Mode to
version 2.3.4)
12MHz oscillator using external crystal.
Integrated power-on-reset circuit.
+3V3 Single Supply Operation with 5V tolerant
inputs.
USB 2.0 Full Speed compatible.
Extended operating temperature range; -40⁰C
to 85⁰C.
Available in compact Pb-free 32 Pin LQFP and
QFN packages (both RoHS compliant).
可以说FT311D功能很强大
后来又推出了FT312D这颗芯片是 专门的Android的USB转UART芯片 内部buffer比FT311D大的多
The FT312D is a USB 2.0 Full Speed
host IC specifically targeted at
providing access to peripheral
hardware from an Android platform
with a USB device port. The device will
bridge the USB port to a UART
interface via the Android Open
Accessory protocol and has the
following advanced features:
Single chip USB to UART interface.
Entire USB protocol handled on the chip. No
USB specific firmware programming required.
USB bulk transfer mode
Basic UART interface with RXD, TXD, RTS#,
CTS# pins.
TX_ACTIVE signal for controlling transceivers
on RS485 interfaces.
UART RX buffer size is 5512 bytes
UART TX buffer size is 256 bytes
USB_ERROR indicator pin
Suitable for use on any Android platform
supporting Android Open Accessory Mode
(Typically 3.1 onwards, however some
platforms may port Open Accessory Mode to
version 2.3.4)
12MHz oscillator using external crystal.
Integrated power-on-reset circuit.
+3V3Single Supply Operation with 5V tolerant
inputs.
USB 2.0 Full Speed compatible.
Extended operating temperature range; -40⁰C
to 85⁰C.
Available in compact Pb-free 32 Pin LQFP and
QFN packages (both RoHS compliant).
Supports bulk transfer mode
听说FTDI有款芯片和CP2102一样功能的芯片，于是在打样的时候也把FT321也 加进去了
板子终于在这周一回来了 焊接好了 测试FT312D开始没有反应，经过仔细查找原来是 D+ D-接反了 ，飞线反了过来 一切ok ，稳定性还在测试 相信这颗芯片比FT311D做usb转串口要好
FT321接到我的W7电脑上 ，显示查找驱动 ，一会自动安装成功，哈哈 我又多了一个 USB转串口，上面还带有TXD RXD的收发指示灯管脚，比较不错。然后我又连接到安卓平板上，结果没有反应，哎不知道什么原因，可能是平板的usb口设计原因吧 不是真正的OTG 。
下面分享一下我的几个测试板，其中一个是FTDI 官方的评估板。
终于解决了Android平板连接stm32串口通信问题了
我这里还有 FT311D FT312D FT321的 空板子 各5块，有需要的可以和我联系哦。数量有限哦
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发表于 2013-8-23 11:08:44
楼主
