
I 2 C M A S T E R / S L A V E I N T E R F A C E
Software driver
456
Hardware Reference NS9215
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S o f t w a r e d r i v e r
I
2
C master
software driver
The I
2
C master software driver uses three commands only:
•
M_READ
to start a read sequence
•
M_WRITE
to start a write sequence
•
M_STOP
to give up the I
2
C bus
If, during a read or write sequence, another
M_READ
or
M_WRITE
is requested by the
ARM CPU, a restart is performed on the I
2
C bus. This opens the opportunity to
provide a new slave device address in the MAster Address register before the
command request.
I
2
C slave high
level driver
The I
2
C slave high level driver identifies one command:
S_STOP
, to discontinue a
transaction. After this command, the slave remains inactive until the next start
condition on the I
2
C bus. If a slave is accessed by a master, it generates
S_RX_DATA
and
S_TX_DATA
interrupts (see “Master/slave interrupt codes” on page 455). To
distinguish the transactions from each other, special
S_RX_DATA_1ST
and
S_TX_DATA_1ST
interrupts are generated for the transmitted byte.
0xB
S_TX_DATA_1ST
Slave
TX data required in register
TX_DATA
, first byte
of transaction
0xC
S_RX_DATA_1ST
Slave
RX data available in register
RX_DATA
, first
byte of transaction
0XD
S_TX_DATA
Slave
TX data required in register
TX_DATA
0xE
S_RX_DATA
Slave
RX data available in register
RX_DATA
0XF
S_GCA
Slave
General call address
Code
Name
Master/slave
Description
Summary of Contents for NS9215
Page 1: ...NS9215 Hardware Reference 90000847_C Release date 10 April 2008...
Page 3: ......
Page 4: ......
Page 26: ...26 Hardware Reference NS9215...
Page 44: ...P I N O U T 26 5 System clock 44 Hardware Reference NS9215 System clock drawing...
Page 52: ...P I N O U T 26 5 Power and ground 52 Hardware Reference NS9215...
Page 80: ...I O C O N T ROL M O D U L E Memory Bus Configuration register 80 Hardware Reference NS9215...
Page 136: ...WOR KI N G W I TH T H E C P U Noncachable instruction fetches 136 Hardware Reference NS9215...
Page 202: ...S Y S T E M C O N T RO L M OD U L E RTC Module Control register 202 Hardware Reference NS9215...
Page 354: ...E X T E R N A L D M A DMA Peripheral Chip Select register 354 Hardware Reference NS9215...
Page 472: ...R E A L TI M E C L O C K M O D U L E General Status register 472 Hardware Reference NS9215...
Page 512: ...TI M I NG Clock timing 512 Hardware Reference NS9215...
Page 515: ...PA CKA GING Processor Dimensions www digiembedded com 515...
Page 516: ...PA CKA GING Processor Dimensions 516 Hardware Reference NS9215...