Datasheet

User Manual Rev. 1.0 — 9 February 2018 10 of 16

NXP Semiconductors

LPCXpresso804

User Manual

Note that the default ports for ISP UART boot are connected to CN2.

5.2 Grove connector

The LPCXpresso804 board includes a header for connection of Seeed Studio Grove I

sensors. This header supplies the I

C connections plus 3.3V and ground.

6. Power supplies and supply current measurement

This section describes available power options for the board, and how current

consumption of the LPC804 can be measured.

6.1 Board powering options

The Board may be powered by the USB connector (CN2), via the Arduino connector (5V

input pin) or by a coin cell battery inserted into the holder on the underside of the board.

When using the coin cell battery switch S4 must be closed to connect the battery.

Protection diodes are provided to prevent any of the possible power sources from back

powering another. Note that the LPC11U3x debug probe can only be powered by USB.

The LPC804 is powered from either a 1.8V or 3.3V (default) regulator, the selection of the

voltage used is made using JP8. The remaining circuitry on the board is always powered

by the 3.3V regulator, with the LPC11U3x debug probe having its own 3.3V regulator.

6.2 LPC804 supply current measurement

JP5 is provided as an insertion point for an ammeter to measure current flow to that MCU.

This jumper is inserted in line between the center pin of JP8 and the VDD supply of the

LPC804. When an ammeter is not being used, a jumper should be installed on JP5.

7. Other board features

This section describes other board features not detailed elsewhere in this document.

7.1 ISP booting and the ISP button

The LPC804 can be forced into ISP boot mode by holding down the ISP button (S2) and

then holding and releasing the Reset button (S3). The ISP button is connected to LPC804

pin PIO0_12, which is also routed to the Arduino expansion connector and to the cathode

of the green user LED3. LPC804 pin PIO0_12 can be reconfigured by software so that the

button can be used by an application as a general purpose button (refer to the LPC804

User Manual).

6 INT PIO0_12 CN6, green user LED

7 UART TX PIO0_4 CN5, CN6, debug UART

8 UART RX PIO0_0 CN7, debug UART

Table 5. Arduino expansion connector pin mappings (CN8)

Pin Arduino signal LPC804 pin Shared with