Keil Logo

Jumper Descriptions

The jumpers used to configure the MCB1800 board are:

  • J1 3V3A: Provides access for measuring analog power consumed by the LPC1850.
  • J1 3V3R: Provides access for measuring CPU power consumed by the LPC1850.
  • J1 3V3IO: Provides access for measuring I/O power consumed by the LPC1850.
  • J2 GND SWO: Provides access to SWO and GND signals for power monitoring equipment such as PowerScale from Hitex.
  • J3 3V3/BAT: Select power source (board or battery power) for the Real-Time clock (RTC).
  • J4A-D P2_9, P2_8, P1_2, P1_1: Selects the boot configuration. The MCU will boot from USART0, USART3, USB0, USB1, SPI Flash or external NOR Flash. See the Boot Configuration Jumpers in Configuring the 1800 for the jumper settings.
  • J5 DBG_EN: Enables the Cortex Debug (J6), Cortex Debug + ETM (J7) and JTAG (J8) debug/download interfaces. Removing this jumper disables all 3 debug/download interfaces.
  • J10 L+R: Combines the left and right channel microphone input allowing a monaural input from a stereo microphone.
  • J14 Codec/DAC: Connects the loudspeaker amplifier to either the left channel line output of the codec or to the digital to analog converter (DAC) output.
  • J13 RX: Connects the RS232 receiver to either UART0(P2_1)See Note or UART3(P2_4).
  • J16 TX: Connects the RS232 transmitter to either UART0(P2_0)See Note or UART3(P2_3).
  • J17 UISP: Enables In-System Programming. Lets the RTS line of the COM0 port generate a signal on P2.7 (INT0). When RTS is active, P2.7 is driven low. This is used to enter In-System Programming (ISP) mode.
  • J18 URST: Enables Reset via the UART0/3 port. When RST is set, you may generate a CPU RESET signal using the DTR signal of the UART0/3 port. An active DTR signal generates a CPU RESET.
  • J19-J20: Provides 120 ohm CAN bus termination between CANH and CANL, when installed.
  • J21 LED_EN: Enables the 8 on-board LEDs. When the port pins assigned to the LEDs are used for other purposes, you may reduce the power required for the board by removing this jumper.


  • Pins P2_0 and P2_1 are shared with the external address bus. DO NOT set these jumpers to the UART0 position if the external address bus is in use.

MCB1800 Board Jumpers

Related Knowledgebase Articles

  Arm logo
Important information

This site uses cookies to store information on your computer. By continuing to use our site, you consent to our cookies.

Change Settings

Privacy Policy Update

Arm’s Privacy Policy has been updated. By continuing to use our site, you consent to Arm’s Privacy Policy. Please review our Privacy Policy to learn more about our collection, use and transfers
of your data.