STC8H8K64U转双串口，第二次板子打样，使用TSSOP20封装芯片

hualu***

j***

Add crystal oscillator frequency stabilization, and the RX2 pin serves as both RX2 output and frequency measurement input (use a small toggle switch).

Good ideas, but the existing STC USB-2UART board already has a 22.1184MHz crystal fitted, so this does not improve much. (I measure about -50ppm too slow)

Suggest you look to fit a TCXO oscillator for better frequency precision ?
This can AC couple through 1nF to XTALI pin

Common TCXO values are 19.2M, 26.000M, 38.4M, 52MHz (overclocked)

lcsc examples:  
KDS Daishinku 1XXA26000MAA VC-TCXO 26MHz voltage trim
TG2016SMN 38.4000M-MCGNNM3 Seiko Epson 2.8V~3.3V Clipped Sine Wave ±500ppb SMD2016-4P

If you want to extend the frequency counter MHz-in range, small logic parts like 74AHC1G4210GW can extend > 100MHz
(or even ~~STC8H2K08U-45I-SOP16~~, it's cheap enough to replace logic. Oops, needs to be STC8H2K08U-45I-TSSOP20 (same price) to have a XTALI pin, for divider input. XTALI is missing on SOP16 )

xxkj***

jmg 发表于 2024-1-25 13:23
Good ideas, but the existing STC USB-2UART board already has a 22.1184MHz crystal fitted, so this d ...

大佬，俺不懂英语的

龙腾***

热烈支持，能把PCB项目分享给大家吗，都来玩玩

ly1***

搞得很好看啊！赞！

国学***

xxkj2010 发表于 2024-1-25 20:41
大佬，俺不懂英语的

还是咱们国语交流起来更方便

xxkj***

国学芯用 发表于 2024-2-4 11:07
还是咱们国语交流起来更方便

是的，用国语方便，包括stc官方例程，我都喜欢看中文注释的。一看到英文注释，就觉得学不下去

hhh***

请问楼主：STC8H8K64U有4个串口，搞成USB转4串口可行吗？

pang***

感谢分享，有PCB链接吗

xxkj***

hhh402 发表于 2024-2-5 01:12
请问楼主：STC8H8K64U有4个串口，搞成USB转4串口可行吗？

没有试过，也不知道怎么处理，这个问题得问stc工程师他们。