DA6501.001
27 October 2008
2
I C SERIAL INTERFACE CONTROL
Serial Interface
MAS6501 has two wire serial I2C bus type interface
comprising of serial clock (SCL) and serial data
(SDA) pins. I2C bus is used to write configuration
data to sensor interface IC and read the
measurement result when A/D conversion has been
finished.
Digital interface includes also master clock (MCLK),
end of conversion (EOC) and master reset (XCLR)
pins.
MLCK signal is needed to be clocked during
conversion period. It can be stopped after EOC
goes high which indicates that A/D conversion has
Device and Register Addresses
I2C bus standard makes it possible to connect
several I2C bus devices into same bus. The devices
are distinguished from each other by unique device
address codes. MAS6501 device address is shown
Table 2.
MAS6501 device address
A7 A6 A5 A4 A3 A2 A1
1
1
1
0
1
1
1
in table 2. The LSB bit of the device address defines
whether the bus is configured to Read (1) or Write
(0) operation.
been accomplished. MCLK signal can also be
running all the time.
XCLR is used to reset the A/D converter. Reset
initializes internal registers and counters. After
connecting supply voltage to MAS6501 and before
starting operating the device via I2C bus it is
required to reset the device with XCLR reset pin if
supply voltage rise time has been longer than 400
ns. If the supply voltage rise time is shorter than this
the external reset with XCLR pin is unnecessary
since the device is automatically reset by power on
reset (POR) circuitry.
W/R
0/1
Control register bits are described in table 1 (page
5). Two other 8-bit registers are used to store the
16-bit A/D conversion result.
MAS6501 contains three 8-bit registers which are
presented in table 3. Control register is used to
configure the device to proper measurement setup.
Table 3.
MAS6501 internal register addresses
A7 A6 A5 A4 A3 A2 A1
A0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
1
1
1
0
1
Register Description
MSB A/D Conversion Result Register
LSB A/D Conversion Result Register
Control register
6 (16)
MAS [ MICRO ANALOG SYSTEMS ]
