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CH340B的问题,有遇到的么?
tom6bj
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发表于2016-12-13 18:10:19 | 显示全部楼层
1# 电梯直达

以1.5Mbps的波特率连续发送时,发几百字节会缺一字节。500kbps或750kbps时一切正常。

手册上说波特率范围是50bps~2Mbps,1.5Mbps还在正常范围内啊?


tom6bj
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发表于2016-12-13 19:31:30   |  显示全部楼层
4#
发表于2016-12-13 18:29:47  2# 波特率有误差的话,连续包太长会出错,建议减少包长度。

发"Hello, world.\r\n",这一帧够短了,也就15字节,结果一样,发几十次就缺一个字节。。。


其实大部分场合也不需要这么快,就是往EEPROM里批量写配置数据时比较有用。


ps. 用示波器看了下8M晶振引脚,8.000300MHz,不到40ppm的误差,对串口来说够精确了吧~

tom6bj
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发表于2017-03-22 09:33:55   |  显示全部楼层
6#

继续在另一块板上实验, 问题照旧.

串口助手接收的数据:


Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, wrld.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, word.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, wold.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello,world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, word.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Helo, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hllo, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello,world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.
Hello, world.


500kbps时一切正常, 用CH340G时1.5Mbps一切正常.


难道这个CH340B就是到不了1.5Mbps?

tom6bj
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发表于2017-03-23 16:31:55   |  显示全部楼层
8#
发表于2017-03-22 10:14:58  7# 不知是不是CH340B本身的BUG,也试了手上的也会有楼主的情况,CH340G和CH340C没有发现。

多谢多谢~~ CH340C没问题? 以后用它试试.

CH340B/C的datasheet里标称到2Mbps, 总该多留点余量. 您再用更高的波特率试试? 72M的stm32, 应该可以到4.5Mbps吧, 48M时可以到3M. 


tom6bj
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发表于2017-03-25 21:57:41   |  显示全部楼层
12#
发表于2017-03-24 20:11:52  9# 你用哪个软件测试的?

sscom32啊, 作者习小猛(大虾丁丁)


大家用的都是这软件吧?

自己写的上位机用的Python

tom6bj
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发表于2017-03-25 21:59:10   |  显示全部楼层
13#
发表于2017-03-24 23:10:48  11# >500kbps时一切正常,用CH340G时1.5Mbps一切正常.>难道这个CH340B就是到不了1.5M...

往设备里批量写入用来查表插值的数据, 当然是越快越好啊. 

平时正常工作倒是9600足够了.

tom6bj
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发表于2017-03-27 09:07:06   |  显示全部楼层
15#
发表于2017-03-26 09:13:34  14# 串口助手是不是最大支持2Mbps?试了2Mbps自收发,CH340G和C没有异常,CH340B有丢数据。

前面选Custom, 然后可以自己填数字啊.

PC这边串口逻辑上估计远不止2Mbps吧, 瓶颈应该在USB上. 

FT232的datasheet里说支持3Mbps, 估计最多也就这样了.


tom6bj
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发表于2017-03-28 11:30:05   |  显示全部楼层
17#
发表于2017-03-27 10:26:58  16# 3Mbps,CH340G和CH340C也会丢数据

赞~~多谢多谢! 辛苦了~

tom6bj
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发表于2019-11-06 15:55:24   |  显示全部楼层
20#
发表于2019-08-13 16:17:07  18# 我也遇到这个问题了,楼主最后怎么解决的

我现在新做板一律只用CP2102和CP2104了,1.5M很稳。不过保险起见只用到500k。

旧板一直用500k,也没再出过问题。


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