Table of Contents
Advertisement
AC75 Hardware Interface Description
Strictly confidential / Preliminary
2
3.13
I
C Interface
2
I
C is a serial, 8-bit oriented data transfer bus for bit rates up to 400kbps in Fast mode. It
consists of two lines, the serial data line I2CDAT and the serial clock line I2CCLK.
The AC75 module acts as a single master device, e.g. the clock I2CCLK is driven by module.
I2CDAT is a bi-directional line.
Each device connected to the bus is software addressable by a unique 7-bit address, and
simple master/slave relationships exist at all times. The module operates as master-
transmitter or as master-receiver. The customer application transmits or receives data only
on request of the module.
To configure and activate the I
two lines I2CCLK and I2DAT are locked for use as SPI lines. Vice versa, the activation of the
SPI locks both lines for I
explanations on the protocol and syntax required for data transmission can be found in [1].
The I
2
C interface can be powered from an external supply or via the VEXT line of AC75. If
connected to the VEXT line the I
enters the Power-down mode. If you prefer to connect the I
supply, take care that VCC of the application is in the range of V
shut down when the PWR_IND signal goes high. See figures below as well as Section 7 and
Figure 46.
In the application I2CDAT and I2CCLK lines need to be connected to a positive supply
voltage via a pull-up resistor.
For electrical characteristics please refer to Table 26.
GSM module
I2CDAT
I2CCLK
GND
Figure 19: I
AC75_HD_V00.202
2
C bus use the AT^SSPI command. If the I
2
C. Detailed information on the AT^SSPI command as well
2
C interface will be properly shut down when the module
2
C interface connected to VCC of application
Page 59 of 120
s
2
C bus is active the
2
C interface to an external power
and that the interface is
VEXT
Application
VCC
w VEXT
R
R
p
p
I2CDAT
I2CCLK
GND
27.04.2006
Advertisement
Table of Contents
