Datasheet

User Manual Rev. 1.0 — 9 February 2018 11 of 16

NXP Semiconductors

LPCXpresso804

User Manual

7.2 User button

The User button (S1) is for general purpose use by LPC804 applications. It is connected

to a 10K ohm pullup to 3.3V, and to the LPC804 PIO0_13 pin. It is also shared with the red

User LED1.

7.3 User LEDs

Three users LEDs are provided on the board, one blue, one green and one red. The

anodes of the LEDs are connected together, then through a zero ohm resistor to the 3.3V

regulator output (each has its own current limit resistor in-line). Each LED has a jumper in

series with it (JP21, JP22 and JP25) to prevent leakage from the LPC804 pins through the

diodes if accurate power measurement measurements are being performed. All the PIOs

used for these LEDs are also shared with the Arduino expansion connector, but those

connections to the expansion connectors are not routed via the jumpers. The LEDs are

connected to the LPC804 as shown in the table below.

7.4 Temperature sensor (LM75, circuit ref U7)

An NXP temperature sensor is included on the LPCXpresso804. This device interfaces to

the I

C peripheral of the LPC804, with an address of 0x1001100. Jumpers (JP4 and JP23)

are provided in-line with the SCL (PIO0_14) and SDA (PIO0_7) respectively so that this

device may be disconnected if not required.

7.5 SPI flash (Winbond W25X10CLSNIG, circuit ref U4)

A 1Mb SPI flash from Winbond is included on the LPCXpresso804. This device interfaces

to the SPI peripheral of the LPC804. A jumper (JP3) is provided to this device can be

disconnected (by disabling the SPI chip select PIO_16).

8. PLU Shield

The OM40001 package includes a shield board for use with the LPCXpresso804 board

when prototyping programmable logic unit (PLU) designs. The PLU shield provides the

following features to assist with this type of development:

• 5 slide switches to enable 5 possible PLU inputs to be connected to VDD (marked as

VCC on the Shield) or GND through a resistor (to set those inputs to a logic 1 or zero)

• 8 LEDs with jumpers to connect/disconnect possible PLU outputs for visual status

indication

• Push button option for momentary / edge signal inputs

• Low frequency oscillator with 1024Hz and 8Hz outputs

Table 6. User LED connections

LED LPC804 pin

Blue (D4) PIO0_11

Red (D3) PIO0_13

Green (D2) PIO0_12