HL7800 mandatory UART0 pins vs HL7692

#1

According to the datasheet, pin C44 (WAKE_UP) is a mandatory connection. If you let it float, the pull-down will prevent the module from starting as far as I understand. On HL7692 this is GPIO13 with no special use. HL7692 uses DTR (actually \DTR) signal for this purpose, and HL7800 also specifies DTR as “wakes the module up”. Is the WAKE_UP mandatory if you’ve got \DTR routed? If it is mandatory, is it enough to connect WAKE_UP to DTR?

Debug UART0 in HL7800 is marked as mandatory as well, in HL7692 this is flat out NC. Do I really need this, can’t I do what is needed via UART1?

Why do I need the debug interface to start with, I’m accessing the firmware via AT commands and have no intent of modifying the firmware in any way or manner?

Spec files:
AirPrime_HL7800_and_HL7800_M_Product_Technical_Specification_Rev6_0.pdf
AirPrime_HL7692_Product_Technical_Specification_Rev7_0.pdf

#2

I just checked MangOH Red, it definitely does not connect the UART0 to a connector. It’s routed to WP module processor pins, which is not that useful if you’re using HL module. The best I could come up with in this instance is to cut traces between U570 and resistors R580, 581, 582 and 583 and use the resistor pads to connect to a 1.8V RS232 interface.

Then again, do I really need UART0 to design our embedded AT command interface??

UART3 is called SPI bus in MangOH red and is actually connected to a header. Too bad UART3 is marked as optional (connect to test point) and UART0 is marked absolutely vital to connect.

What if I connect UART0 in our cellular board to test points and ignore it otherwise? And maybe chop the MangOH red board so I can hook it to a serial adaptor?