MLX90609

Angular Rate Sensor (Standard version)

390109060901

Page 14 of 22

Data Sheet

Rev 008

February/08

5.3.2 Reading the Digital Angular Rate or Temperature (suggested procedure)

There is a recommended sequence below to obtain digital data from the ADC.

Notes:

- The bit with leftmost position should be shifted first.

- Below “x” means any value: “0” or “1”.

•

Step 1 (put ADC to the active mode if it wasn’t)

Use SPI to send ADCC instruction (MOSI): 1 0 0 1 x 1 0 0 x x x x x x x x x x x x x x x x

And check 15th bit of the answer (MISO):

0 x x x x x x x x x x x x x x x

If 15

th

bit is zero, the instruction is accepted.

Before to go to the Step 2 provide a delay > 115 µs or wait till the EOC bit is set.

•

Step 2 (conversion start)

Use SPI to send ADCC instruction(MOSI):1 0 0 1 CHAN 1 0 0 x x x x x x x x x x x x x x x x

And check 15th bit of the answer (MISO):

0 x x x x x x x x x x x x x x x

If 15

th

bit is zero, the instruction is accepted.

CHAN bit specifies the input source of the ADC.

CHAN=0: The angular rate signal.

CHAN=1: The temperature sensor signal.

Go to the Step 3.

•

Step 3 (polling and result obtaining)

Use SPI to send ADCR instruction and check 15

th

and 13

th

bits of the answer:

1

0

0

0

0

0

0

0

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

0

x EOC x

AD10 AD9 AD8 AD7 AD6 AD5 AD4 AD3 AD2 AD1 AD0 0

If 15

th

bit is zero, the instruction is accepted.

If

13

th

bit

(EOC)

is zero,

the

conversion

is

still

in

progress and

the

result

of

the

conversion (bits AD10…AD0) is not valid. As soon as the EOC bit is set the conversion is

completed and the result is valid.

Instead of the polling of the EOC bit one can use a simple delay that should be bigger

than a maximal conversion time (>115 µs, see table 4).

Go to the Step 2 to do the next conversion or to the Step 4 to put ADC to the sleep mode.

•

Step 4 (put ADC to the sleep mode if it’s necessary)

Use SPI to send ADCC instruction (MOSI):

1 0 0 1 x 0 0 0 x x x x x x x x x x x x x x x x

And check 15th bit of the answer (MISO):

0 x x x x x x x x x x x x x x x

If 15

th

bit is zero, the instruction is accepted.