pHAT Module Series

pHAT-RV Technical Description

pHAT-RV Technical Description

Page 13 of 27

3.7 I

2C Interface

3.7.1 I

2C Interface Pins

The RV provides I

2C data (SDA) and clock (SCL) connections on the 20+20 header that connect

to the SDA and SCL on the Raspberry-Pi board. The table below describes the module I

2C pins.

Table 3: I

2C Interface Pins

Pin Name

Pin No

I/O

Description

Comment

SDA

3

DIO

I2C Data

3.3V level

SCL

5

CO

I2C Clock

3.3V level

The RV does NOT have I

2C pullups but relies on the pullups present on the Raspberry-Pi board.

When not connecting to a Raspberry-Pi board external pullups of 4.7Kohms should be

connected on SDA and SCL to a 3.3V supply.

3.7.2 I

2C Communication

Up to four RV modules may be connected to the same Raspberry-Pi board or I

2C bus and

accessed individually using their own individual address.

The following table shows how the pads are soldered for the different binary addresses.

Table 4: I

2C Address Settings

Address (xx)

A0

A1

00

OPEN

OPEN

01

SHORT

OPEN

10

OPEN

SHORT

11

SHORT

SHORT

The binary address (xx) above is used in conjunction with the device ID 11101xxD (0xE8hex) to

form the complete device address i.e. if both jumpers are left unconnected (default) then the

device address would be 1110100Dbinary.

The ‘D’ bit determines if a read or a write to the RV is to be performed. If the ‘D’ bit is set ‘1’

then a register read is performed or if clear ‘0’ a register write.