UM980 User Manual
10 Hardware UC-00-M32 EN R1.1
Reserved, recommended to be floating
Built-in function; recommended to add a
through-hole testing point and a 10 kΩ pull-
up resistor; cannot connect ground or power
supply, and cannot be peripheral I/O, but can
be floating
Built-in function; recommended to add a
through-hole testing point and a 10 kΩ pull-
up resistor; cannot connect ground or power
supply, and cannot be peripheral I/O, but can
be floating
COM3 output, can be used as CAN TXD,
LVTTL level
COM3 input, can be used as CAN RXD, LVTTL
level
When the main power supply VCC is cut off,
V_BCKP supplies power to RTC and relevant
register. Level requirement: 2.0 V ~ 3.6 V, and
the working current should be less than 60
μA at 25 °C. If you do not use the hot start
function, connect V_BCKP to VCC. Do NOT