User's Manual

GSM/GPRS/GNSS Module Series
MC20 Hardware Design
MC20_Hardware_Design Confidential / Released 48 / 95
Figure 18: Reference Design for UART Port with Hardware Flow Control
3.6.1.3. Firmware Upgrade
TXD and RXD can be used for firmware upgrade in both all-in-one solution and stand-alone solution.
The PWRKEY pin must be pulled down before firmware upgrade. A reference circuit is shown as below:
Figure 19: Reference Design for Firmware Upgrade
1. In stand-alone solution, make sure the Auxiliary UART Port is connected to the GNSS UART Port
during firmware upgrade. Please refer to Chapter 3.6.3.2 for details.
2. The firmware of module might need to be upgraded due to a certain reasons. It is thus recommended
to reserve these pins in the host board for firmware upgrade.
NOTES