NXP Semiconductors LPCXpresso804, Руководство пользователя

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UM11083 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2018. All rights reserved.
User Manual Rev. 1.1 — 24 September 2018 13 of 16
NXP Semiconductors
LPCXpresso804
User Manual
By enabling PIO0_11 as a DAC output, a test signal can be driven to a circuit probe
connected to JP3, then the voltage at the voltage divider formed by R18 and R20 can be
measured using an LPC804 ADC input (PIO0_19). In order to use this circuit it is
recommended that R15 is removed and S3 set to the VCC position.
9. Capacitive Touch Shield
The OM40001 package includes a shield board for evaluation of the LPC804 capacitive
touch feature. The Capacitive Touch Shield provides the following features:
•
5 capacitive touch buttons
•
5 LEDs, available for user applications (typically to indicate a button press)
The connections for the capacitive touch buttons are shown in Table 9 . As some signals
are shared with other functions, the jumpers shown in the table should be removed from
the LPCXpresso804 board when using the capacitive touch shield.
The five user LEDs are active low (on when control signal is at logic 0). The signal
assignments are shown in
Table 10 . Note that PI00_8 and PIO0_9 are also connected to
the SPI flash data inputs/outputs, so it is advisable to remove JP3 on the LPCXpresso804
board (to disable the SPI flash memory) before installing this shield board.
Table 9. Capacitive touch button signals
Button LPC804 I/O Capacitive touch signal Shared with / remove jumper
S1 PIO0_12 CAPT_X0 User LED / JP22
S2 PIO0_21 CAPT_X1
S3 PIO0_13 CAPT_X2 User LED / JP25
S4 PIO0_11 CAPT_X3 User LED / JP21
S5 PIO0_19 CAPT_X4
Common PIO0_7 CAPT_YL LM75 / JP23
Common PIO0_16 ACMP_I4 (not used by default) (not used)
Common PIO0_17 CAPT_YH