5
MISO
SPI: Master In / Slave Out
5
Green
GND
Ground
6
Blue
MOSI
SPI: Master Out / Slave In
7
violet
SDA
I2C: serial data
8
Gray
GND
Ground
9
White
IN
GPIO input
10
Black
SCLK
SPI: master clock
11
Brown
OUT
GPIO output
12
Red
3.3V
Switched 3.3V
13
Orange
5V
Switched 5.0V
14
yellow
VCC
is the 3.3V power for the USB-to-
I2C hardware. This supply is active
whenever the hardware is plugged into
a USB port. It is provided here to supply
the pull-up resistors. It can also be
used to power a user’s target hardware.
VP
– supplies the power to the I²C pull-
up resistors (see RPU). Note that the
USB-to-I2C hardware by default has the
jumpers connected at RPU and it is up
to the user to ensure that a voltage
source is connected to the VP pin. A
pull-up voltage, up to 5.5V maximum,
may be applied to the VP pin. If pull-up
resistors are not required, please
remove the two jumpers at connector RPU. It is not be necessary to apply a voltage at VP if
the RPU jumpers are not installed.
SPI Port
– the SPI signals are connected to the target system from this port. Note that
these signals drive a 3.3V output.
To communicate with a SPI slave, you require four signals and GND:
SSN
– Slave Select (also known as CS or Chip Select)
MISO
–
M
aster
I
n
S
lave
O
ut is connected to the SPI slave output
MOSI
–
M
aster
O
ut
S
lave
I
n is connected to the SPI slave input
SCLK
–
S
erial
Cl
ock outputs the clock to the slave device
The SPI pins may be used as IO pins controlled by the DLL, if not used for SPI functionality.
I²C Port
– connect these two pins (SDA and SCL) and GND to your target system. Details
can be found in the section titled “USB-to-I2C Hardware To Target Connection” of this
document.
SCL
– is the serial clock generated by the USB-to-I2C hardware. Clock stretching is
supported.
SDA
– is the bidirectional I²C data pin.
Supply a voltage at VP for the pull-up resistors or remove the jumpers at RPU before using
the I2C port. It is advisable to remove the jumpers when connecting the USB-to-I2C
hardware to a target system, assuming the target already has pull-up resistors. This will
allow you to use the USB-to-I2C hardware at the voltage of your target system.
