Datasheet

UM11083 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2018. All rights reserved.
User Manual Rev. 1.0 — 9 February 2018 12 of 16
NXP Semiconductors
LPCXpresso804
User Manual
The PLU shield also includes a test circuit that can be used to implement a simple
continuity tester, for experimentation with the LPC804 ADC and DAC (requires some
shield board modification.)
Several signals from the LPC804 used on the PLU Shield are shared with other functions
on the main LPCXpresso804 board. Please review jumper settings on the
LPCXpresso804 board carefully before installing the PLU Shield.
The PLU can be programmed using a PLU Configuration tool, available to download for
free at https://www.nxp.com/demoboard/OM40001 under the Software and Tools tab.
8.1 PLU input options
On/off switches S1 through S5 connect possible PLU inputs to VDD or GND via a resistor,
enabling those inputs to be driven to a known, fixed state. PIO0_8 is connected to a push
button (S6) and a 100kohm pull up to VDD; PIO0_8 will be grounded when the button is
pressed. Table 7 below shows these connections.
A digital oscillator circuit is also included on the Shield, with 1.024kHz and 8Hz outputs
available. LPC804 signal PIO0_1 can be connected to these oscillator signals in order to
provide a low speed clock to the flip-flops in the PLU block. The center pin (2) of JP12
connects to PIO0_1, so a jumper can be placed onto JP12 to connect this signal to the
required clock (see markings on the Shield silk screen.) An external clock can be provided
to the PLU by connecting it to the center pin of JP12.
8.2 PLU output options
On/off switches S1 through S5 connect possible PLU inputs to VDD or GND via a resistor,
enabling those inputs to be driven to a known, fixed state. PIO0_8 is connected to a push
button (S6) and a 100kohm pull up to VDD; PIO0_8 will be grounded when the button is
pressed. Table 7 below shows these connections.
Table 7. PLU input on/off switches
Switch LPC804 signal Notes
S1 PIO0_0 Also connected to debug UART. Remove JP2 to avoid conflicts
S2 PIO0_10 Shared with potentiometer. Move potentiometer to center position to
avoid conflicts.
S3 PIO0_11 Also connected to user LED; remove JP21 to disconnect LED
S4 PIO0_4 Also connected to debug UART. Remove JP24 to avoid conflicts
S5 PIO0_13 Also connected to user LED; remove JP25 to disconnect LED.
S6 PIO0_8 Also connected to SPI flash data input.
Table 8. PLU shield LEDs
LED LPC804
signal
Jumper installed
to enable
Notes
D1 PIO0_15 JP6
D2 PIO0_16 JP7
D3 PIO0_10 JP8 Ensure S2 is in VCC position to use.
D4 PIO0_18 JP9
D5 PIO0_12 JP10 Also used for green User LED. Remove JP22 to
isolate.