ADUC834 Datasheet, PDF (46/80 Pages) Analog Devices – MicroConverter, Dual 16-Bit/24- Bit ADCs with Embedded 62 kB Flash MCU

ADuC834
I²C SERIAL INTERFACE
The ADuC834 supports a fully licensed* I²C serial interface. The
I²C interface is implemented as a full hardware slave and software
master. SDATA (Pin 27) is the data I/O pin and SCLOCK
(Pin 26) is the serial clock. These two pins are shared with the
MOSI and SCLOCK pins of the on-chip SPI interface. Therefore
the user can only enable one or the other interface at any given
time (see SPE in Table XXI). Application Note uC001 describes
the operation of this interface as implemented and is available from
the MicroConverter website at www.analog.com/microconverter.
Three SFRs are used to control the I²C interface. These are described below.
I2CCON
SFR Address
Power-On Default Value
Bit Addressable
I²C Control Register
E8H
00H
Yes
Table XXII. I2CCON SFR Bit Designations
Bit
Name
7
MDO
6
MDE
5
MCO
4
MDI
3
I2CM
2
I2CRS
1
I2CTX
0
I2CI
Description
I²C Software Master Data Output Bit (Master Mode Only).
This data bit is used to implement a master I²C transmitter interface in software. Data written to this
bit will be outputted on the SDATA pin if the data output enable (MDE) bit is set.
I²C Software Master Data Output Enable Bit (Master Mode Only).
Set by the user to enable the SDATA pin as an output (Tx).
Cleared by the user to enable SDATA pin as an input (Rx).
I²C Software Master Clock Output Bit (Master Mode Only).
This data bit is used to implement a master I²C transmitter interface in software. Data written to
this bit will be outputted on the SCLOCK pin.
I²C Software Master Data Input Bit (Master Mode Only).
This data bit is used to implement a master I²C receiver interface in software. Data on the SDATA
pin is latched into this bit on SCLOCK if the data output enable (MDE) bit is 0.
I²C Master/Slave Mode Bit.
Set by the user to enable I²C software master mode.
Cleared by user to enable I²C hardware slave mode.
I²C Reset Bit (Slave Mode Only).
Set by the user to reset the I²C interface.
Cleared by user code for normal I²C operation.
I²C Direction Transfer Bit (Slave Mode Only).
Set by the MicroConverter if the interface is transmitting.
Cleared by the MicroConverter if the interface is receiving.
I²C Interrupt Bit (Slave Mode Only).
Set by the MicroConverter after a byte has been transmitted or received.
Cleared automatically when the user code reads the I2CDAT SFR (see I2CDAT below).
I2CADD
Function
SFR Address
Power-On Default Value
Bit Addressable
I2CDAT
Function
SFR Address
Power-On Default Value
Bit Addressable
I²C Address Register
Holds the I²C peripheral address for the part. It may be overwritten by the user code. Application Note uC001
at www.analog.com/microconverter describes the format of the I²C standard 7-bit address in detail.
9BH
55H
No
I²C Data Register
The I2CDAT SFR is written by the user to transmit data over the I²C interface or read by user code to
read data just received by the I²C interface. Accessing I2CDAT automatically clears any pending I²C
interrupt and the I2CI bit in the I2CCON SFR. User software should only access I2CDAT once per
interrupt cycle.
9AH
00H
No
* Purchase of licensed I²C components of Analog Devices or one of its sublicensed associated companies conveys a license for the purchaser under the Philips I²C
Patent Rights to use these components in an I²C system provided that the system conforms to the I²C Standard Specification as defined by Philips.
–46–
REV. A