MPR031 データシートの表示（PDF） - Unspecified

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MPR031

Proximity Capacitive Touch Sensor Controller

Unspecified 

2.3.6 Message Format for Writing the MPR03X

A write to the MPR03X comprises the transmission of the MPR03X’s keyscan slave address with the R/W bit set to 0, followed

by at least one byte of information. The first byte of information is the command byte. The command byte determines which

register of the MPR03X is to be written by the next byte, if received. If a STOP condition is detected after the command byte is

received, the MPR03X takes no further action (Figure 10) beyond storing the command byte. Any bytes received after the

command byte are data bytes.

Command byte is stored on receipt ofSTOP condition

acknowledge from MPR03X

D15 D14 D13 D12 D11 D10 D9 D8

S

SLAVE ADDRESS

0A

COMMAND BYTE

AP

R/W

acknowledge from MPR3X

Figure 10. Command Byte Received

Any bytes received after the command byte are data bytes. The first data byte goes into the internal register of the MPR03X

selected by the command byte (Figure 11).

How command byte and data byte

map into MPR03X's registers

acknowledge from

MPR03X

D15 D14 D13 D12 D11 D10 D9 D8

acknowledge from

MPR03X

D7 D6 D5 D4 D3 D2 D1 D0

acknowledge from MPR03X

S

SLAVE ADDRESS

0A

COMMAND BYTE

A

DATA BYTE

AP

R/W

1 byte

Figure 11. Command and Single Data Byte Received

auto-increment memory

word address

If multiple data bytes are transmitted before a STOP condition is detected, these bytes are generally stored in subsequent

MPR03X internal registers because the command byte address generally auto-increments (Section 2.4).

2.3.7 Message Format for Reading the MPR03X

MPR03X is read using MPR03X's internally stored register address as address pointer, the same way the stored register address

is used as address pointer for a write. The pointer generally auto-increments after each data byte is read using the same rules

as for a write (Table 5). Thus, a read is initiated by first configuring MPR03X's register address by performing a write (Figure 10)

followed by a repeated start. The master can now read 'n' consecutive bytes from MPR03X, with first data byte being read from

the register addressed by the initialized register address.

acknowledge from MPR03X

acknowledge from master

D7 D6 D5 D4 D3 D2 D1 D0

S

SLAVE ADDRESS

1A

DATA BYTE

AP

n bytes

R/W

auto-increment memory

word address

Figure 12. Reading MPR03X

MPR03X

6

Preliminary

Sensors

Freescale Semiconductor

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