I am working on a design of a prototype with HL8548 module. It consists on a microcontroller connected by UART to the modem. This microcontroller handles the HL8545 by AT commands in order to stablish TCP connections.
When a TCP is stablished, this UART interface turns to data mode, so I will not be able to detect modem unsolicited messages during TCP communication. For this reason, I would like to have one more interface in order to detect them.
For that, two UARTs will be the best option, but I checked that this module only has one UART. Anyway, I realized that HL85 has a USB interface (USB_D+ and USB_D-) which may be great to monitor these messages.
What do you think about using it? I suppose that I need a microcontroller with OTG USB.
I would like to get any idea/opinion because maybe I am wrong.