User's Manual

COMPANY CONFIDENTIAL
25
The pinout and signal names are shown on the next page. The following table provides an overview for the most important
control and interface signals.
8.2.1 Pin Descriptions
Signal(s)
Type
Description
POWER
VIN(+3.3V)
P
Power supply input ; +3.3V.
VIN (+1.2V)
P
Power supply input ; +1.2V.
VIN (+1.9V)
P
Power Supply input; +1.9V for powering RF section. Make sure this is a clean supply.
3V3RTC
P
The RTC function is no longer supported. This pin should be left open.
GND
P
Ground (GND) connection for power supply 0V, signal returns and shielding.
SPI
SPI_DOUT
O
SPI data from DM870A to host controller.
SPI_DIN
I
SPI data from host controller to DM870A.
SPI_CLK
I
SPI clock from host controller to DM870A. Maximum recommended frequency is 2MHz,
typical frequency is 1MHz. See Note 2 below.
SPI_NCS0
I
SPI chip select from host controller to DM870A.
PDOUT1
O
This signal is used as SPI_REQ, SPI request signal, from DM870A to host controller for
eDMP applications. Logic 1 indicates that there is an SPI message waiting to be read, the
host controller should start the SPI clock and read any changed registers. Logic 0
indicates that all changed register messages have been read and the message buffer is
empty. Also GPIO-06.
SPI_NCS1
I
Not used. Leave open.
UART
RXD1
I
UART1 input to the DM870A, used for shell access. SMSC recommends providing a
connection to an external RS-232 transceiver and DB9 connector to connect to a PC COM
port. Such a connection can be used for product development debugging, and for module
programming control on the product manufacturing line and for module control during
certification procedures.
TXD1
O
UART1 output from the DM870A, used for shell access. SMSC recommends providing a
connection to an external RS-232 transceiver and DB9 connector to connect to a PC COM
port. Such a connection can be used for product development debugging, and for module
programming control on the product manufacturing line and for module control during
certification procedures.
RXD0
I
UART0 input. Optionally used for controlling an iPod via UART.
TXD0
O
UART0 output. Optionally used for controlling an iPod via UART.