DA6505.005
11 June 2018
REGISTER AND EEPROM DATA ADDRESSES
MAS6505 includes a 64 byte (512 bit) non-volatile
EEPROM data memory and twenty registers. See
table 1 on the previous page presenting register and
EEPROM data addresses of the MAS6505. The
address values differ whether I2C or SPI serial bus
communication is used.
The
Control
register
(EF/6FHEX
)
contains
measurement resolution and operating mode
selection settings. Writing to the Control register
starts the selected measurements. See table 4.
The Status register (F0HEX) contains various status
flags. The FIRSTT and FIRSTP flags are for internal
use only. When being high (1) they indicate that the
running measurement is the first one after starting
the normal mode (continuous) measurements. The
forced mode measurements (single measurements)
are always considered as first measurements so the
FIRSTT and FIRSTP are always high (1) for them.
They are reset right after the first measurement has
ended. The RDYT and RDYP flags indicate when
unread temperature and pressure results are
available at the result registers. Checking status of
these two flags can be used to decide when to read
out new measurement results. See table 5.
In the SPI serial bus the address bit A7 selects
between write (A7=0) and read (A7=1) operation.
In the I2C serial bus the address bit A7 value is
always one (A7=1). Selection between write and
read operation is done by the LSB bit of the I2C
device address (write LSB=0, read LSB=1) but the
register addresses are the same for both write and
read operation. The MAS6505 I2C device address is
EA/EBHEX for write/read. See also Table 12.
The first 58 bytes (464 bits) of EEPROM memory
(addresses 80/00HEX…B9/39HEX) are free for storing
sensor calibration and other data. The last six
EEPROM memory bytes (48 bits) are reserved for
trim data purposes and they are marked with note
“E+T” in the Table 1. EEPROM oscillator frequency
trim address (BA/3AHEX) must be left untouched
since it contains factory trimming value of the internal
The 24-bit measurement result of pressure is stored
into three registers F1HEX (MSB, most significant
byte), F2HEX (LSB, least significant byte), F3HEX
(XLSB, extra least significant byte).
The 24-bit measurement result of temperature is
stored into three registers F4HEX (MSB, most
significant byte), F5HEX (LSB, least significant byte),
F6HEX (XLSB, extra least significant byte).
EEPROM
oscillator.
Temperature
sensor
configuration EEPROM address (BB/3BHEX) is for
storing the temperature sensor selection and bridge
resistance trim settings. Pressure gain trim
EEPROM address (BC/3CHEX) is for storing pressure
measurement AFE gain trim settings. Similarly
Temperature gain trim EEPROM address
Three Test input data registers (F7/77…F9/79HEX
are for IIR filter testing purpose only.
)
Trim and test register (FA/7AHEX) is for trimming and
testing purposes. The TRIM bits define whether the
trim settings are taken from the EEPROM TRIM=00
(default setting) or from the corresponding trim data
registers TRIM<>00. See table 6 for details. The
Trimming mode (TRIM=01 or 10) is for trimming the
temperature sensor and also the AFE gain and the
ADC offset in both temperature and pressure
measurements. There is also Trim test mode
(TRIM=11) but it is for internal clock oscillator
trimming and testing purpose only.
(BD/3DHEX
)
is for storing the temperature
measurement AFE gain trim settings. Temperature
and pressure offset trim EEPROM address
(BE/3EHEX) is for storing the temperature and
pressure measurement ADC offset trim settings. The
last EEPROM memory byte (8 bits) in the EEPROM
address BF/3FHEX is reserved for storing trimming
value of factory trimmed internal 250 kHz clock
oscillator. Also this EEPROM address must be left
untouched to not lose the factory trimming value.
There are five trim data registers in addresses
FB/7BHEX…FF/7FHEX. They have equivalent function
storage space in the non-volatile EEPROM
addresses BB/3BHEX… BF/3FHEX. When selecting
the Trimming mode (TRIM=01 or 10) in the Trim and
test register the temperature sensor, AFE gain and
ADC offset trimming can be done using fast register
write operation instead of using much slower
EEPROM write operations. After optimal trim register
values are found they can be stored into the
corresponding EEPROM trim data addresses. In the
default TRIM=00 setting all the stored trimming
settings will be automatically read to registers from
the EEPROM memory in the beginning of each
measurement.
Reset register (EC/6CHEX) does not contain any data.
Writing any data byte to this register forces a device
reset. The reset initializes all control registers
(addresses EDHEX…FFHEX) to a default zero value.
EEPROM control register (ED/6DHEX) is used for
activating EEPROM (EON bits) which is necessary
in both EEPROM read and write. Additionally for
write operation the EEPROM has to be enabled for
write (EWE bits) since by default the EEPROM write
is disabled. See table 2.
The Configuration register (EE/6EHEX) contains delay
and IIR filter measurement configuration settings
and also selection between 4- and 3- wire modes of
the SPI bus. See table 3.
15 (44)
MAS [ MICRO ANALOG SYSTEMS ]
