VERSION 1.4
JN30 (38346-X)
MCU
The JN30 features an on-board micro controller (MCU: STM32F042F6P6) with 32 kByte Flash and 6kByte RAM. It
monitors the power input rail and resets the Nano, if it discovers a brown out condition (voltage drop). Also it
controls the UART1 bypass and the auto flashing.
MCU pin description
Pin types:
PP - push/pull output
OD - open drain output
Ain - analog input
AF - alternate function
IO - Input/Output
The power supply to the MCU is supplied by a 3.3V LDO regulator which is always on. So the MCU is powered as
soon as power is applied to the power input on J1. This allows the MCU to manage whether power should be
applied to the carrier board.
The MCU tunnels the console UART interface to the Jetson Nano. Some instructions are intercepted by the MCU
and executed by it. These instructions are not forwarded to the compute module.
UART1 Bypass *
„1“ - UART0 Jetson debug interface is tunneled through MCU
MCU Pin
Name
Type
Function
Description
1
PB8/BOOT0
-
-
10k pull down
2
PF0
OD
POWER
1: inactive, 0: press power button
3
PF1
O
POWER
Power enable
4
NRST
-
-
hardware power on reset of MCU (RC circuit)
5
VddA
-
-
analog 3.3V supply (by always on LDO)
6
PA0
Ain0
V12_IN
measure input voltage (voltage divider: 100k up/10k
down)
7
PA1
OD
SYS_RST_IN
System reset; open drain 1.8V
8
PA2
AF
UART1_RX
UART 1 to Nano (debug console)
9
PA3
AF
UART1_TX
UART 1 to Nano
10
PA4
PP
LED
0: LED off, 1: LED on (default MCU heartbeat)
11
PA5
AIN5
CM_PWR_ON Compute module power on; 5V to Nano
12
PA6
AIN6
V5_IN
measure micro USB rail (voltage divider: 10k up/10k
down)
13
PA7
IO
UART_BY
UART1 bypass *
14
PB1
Ain9
SHTDWN_REQ Shutdown request
15
GND
-
-
Ground
16
VddA
-
-
digital 3.3V supply (by always on LDO)
17
PA9/PA11
AF
UART_TX
UART_TX to J14 connector (pin 2)
18
PA10/PA12
AF
UART_RX
UART_RX to J14 connector (pin 3)
19
PA13
-
SWDIO
SWD programming interface
20
PA14
-
SWCLK
SWD programming interface
AUVIDEA GMBH
TECHNICAL REFERENCE MANUAL
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