User manual

LPC4357 Developer’s Kit - User’s Guide
Page 24
Copyright 2013 © Embedded Artists AB
4.12 SP8: Digital IO
There is a push-button (SW6) that is connected to a signal that enable the ISP-mode after reset on the
OEM Board. For the LPC4357 this is pin P2_7. If this pin is sampled low after reset, the ISP-mode for
the LPC4357 is entered. LED30 is positioned above SW6 and will light when SW6 is pressed. It is also
possible to control LED30 as an output from the OEM Board without damaging the output driver when
SW6 is pressed. R110 limits the current.
There is also a 5-key joystick that directly connects to five general purpose input/output pins. See
picture below for locating SW6 and SW7.
Figure 13 – Digital IO
Signals
LPC4357
GPIO_10
Open collector driver on P2_7. This signal is an input only
on the the LPC4357 OEM board and can only be used to
pull P2_7 low, i.e., enable ISP mode after a reset.
GPIO_73
PA_1
GPIO_74
PA_2
GPIO_75
PA_3
GPIO_76
P9_0
GPIO_77
P9_1
4.13 SP8: Serial Expansion Connector
The Serial Expansion Connector is a standardized serial interface connector that is included on many
boards from Embedded Artists, including the OEM Base Board. The purpose is to provide a simple
expansion connector for smaller expansion modules. Such modules are typically sensors of different
kinds and communication modules, but can also be smaller displays.
The connector contains 14 pins that support SPI, UART and I2C communication. Four additional pins
exist for specific functionality, like module reset, interrupt pins, analog signals and pwm signals. Power
(3.3V) is also provided. Maximum current consumption of the external module is 250mA. All signals
are protected with 470 ohm series resistors to minimize current in case of shorts to ground, +3.3V, or
similar.
Usage of the different signals is specific for each module connected. All signals can be configured as
either main function or alternatively as a general purpose input/output signal (GPIO). The picture below
show where the connector can be found and the table lists which pins are connected. The application
program has the responsibility to program the individual pins to correct state/function.
Note that the UART channel is not directly connected to USART channel #3 on the LPC4357. It is
multiplexed with other UART channels, see section 4.15 for details. Also note that the Serial Expansion
5-key Joystick
SW7
Push-button
SW6