Hi,
We are using LC29HAAMD GNSS module in our design. Datasheet of the part and reference application of this module provided by Quectel give some confusion. I am referring to LC29H Series Reference Design V1.2 which connects VDD_EXT to level translator for TXD1 pins etc which is 1.8V domain. But HW design manual mentions VDD_EXT as 2.8V. So how TXD1 etc signals which are 1.8V level domain be pulled to VDD_EXT which is 2.8V domain? Just wondering if HW design document has wrongly mentioned VDD_EXT typical voltage as 2.8V instead of actual 1.8V?
Regards
Narendra Singh
Hi @Narendra
I am not clear about your question.
Could you provide more detail about your question, like a screenshoot with instruction.
LC29H’s UART1(TX1/RX1) is 2.8V, Pulled by VDD_EXT(2.8V). You could refer hardware design document and refering design document.
Best regards.
Hi Jasper,
Thanks for your kind attention to the subject. Please find my query in attached document.
As VDD_EXT is 2.8V output but TXD and RXD pins of module are 1.8V rated, will adding R305 and R306 pull up to 2.8V level(VDD_EXT) not affect RXD/TXD signals which are 1.8V level?
GNSS Query.pdf (396.1 KB)
Please let me know if you need further clarification.
Regards
Narendra Singh
Hi @Narendra
The photo as follows: the place of your mark is I2C pin, which is supportde by 2.8V, so that’s not have issue. And UART1 is supported by 2.8V, UART2’s voltage domain si 1.8.
Best regards
Thanks Jasper for clarification.
Regards
Narendra Singh