MPR083

Sensors

18

Freescale Semiconductor

Preliminary

6.4

Error

The MPR083 can generate a fault under two conditions; an electrode is shorted to VDD, or an electrode is shorted to VSS. Once

a fault is asserted the sensor electrodes will no longer be scanned until the fault is cleared. In the event of multiple faults occurring

at the same time, the sensor controller will report the first fault that is detected during scanning.

6.4.1

Fault Register

The Fault Register is a read only register that shows the fault number under the current sensor conditions. Any write to the Fault

slave address of the Fault Register is 0x01.

Figure 22. Fault Register

Table 13. FIFO Register Field Descriptions

Field

Description

7

MDF

More Data Flag – The More Data Flag shows whether or not data will remain in the

buffer after the current read.

0 No Data Remaining

1 Data Remaining

6

NDF

No Data Flag – The No Data Flag shows whether or not there is currently data in

the buffer.

0 Buffer currently has data

1 Buffer does not currently have data

5

OF

Overflow Flag – The Overflow Flag shows whether or not an overflow has occurred.

If this flag is high then the most current data was lost.

0 No Overflow has occurred

1 Overflow has occurred

4

TRF

Touch Release Flag – The Touch Release Flag shows if the current buffer entry is

a touch or release of a pad.

0 Pad is released

1 Pad is touched

3:0

BP

Buffered Position – The Buffered Position represents the electrode number that is

currently being displayed by the buffer.

0000 Encoding 0 – Buffered touch of electrode 1

~

0111 Encoding 7 – Buffered touch of electrode 8

7

6

543210

R0

0

0

0

0

0

FAULT

W

Reset:

0

0

000000

= Unimplemented

Table 14. Fault Register Field Descriptions

Field

Description

1:0

FAULT

Fault – The Fault code represents the currently asserted fault condition.

00 Encoding 0 – No fault detected

01 Encoding 1 – Short to VSS detected

10 Encoding 2 – Short to VDD detected