MC44S803EP FREESCALE [Freescale Semiconductor, Inc], MC44S803EP Datasheet - Page 9

• Manufacturer Part Number: MC44S803EP
• Description: Low Power CMOS Broadband Tuner
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Freescale Semiconductor
required to read out a particular Data Register. Note that
when using the SPI interface, since there are separate lines
for data in (MOSI) and data out (MISO), each SPI operation
document.
I
separate select line, each IC on the bus has a unique
address. This address is sent each time an IC is
communicated with. The address is the first seven bits that
are sent to the IC. The eighth bit sent is the R/W bit, it
determines whether the master will read from or write to the
IC. Five fixed bits and two pin selectable bits set the address
of this IC. Address bit 2 is set with the MISO/Addr2 pin.
Address bit 1 is set with the SS/Addr1 pin.
Table 9. I
2
MSB
C DEVICE ADDRESS
The following flowchart is provided to show the steps
There are three type of addresses referred to in this
Since the I
7
1
2
6
1
C IC Address
2
C bus is a two-wire bus that does not have a
5
0
IC Address
4
0
innocuous command is sent
The desired Data Register
3
0
Data coming out of MISO
line is from the previously
The desired Data is read
SPI Interface
selected Data Register
SS line is brought high
SS line is brought high
data Register Address
SS line is brought low
Address is sent to the
SS line is brought low
Next Command or an
out on the MISO line
Control Register
X
2
X
1
READ OPERATION PROTOCOL
Figure 4. Read Operation Protocol
R/W
X
ADDRESSES
LSB
is both a read and a write operation. But the data being read
out is not affected by the command that is actively being
written to the IC. The command doesn’t take effect until the
SPI operation is completed.
CONTROL REGISTER ADDRESS
corresponding Control Register. The Control Register
Address specifies which command is being sent.
DATA REGISTER ADDRESS
IC. The Data Register Address specifies which register is
read during the next read operation. The address of the
desired data register is stored in the Control Register called
Data Register Address.
Each command that is sent to the IC is stored in its
There are 16 registers for data that can be read from the
The desired Data Register
I
2
data Register Address
Start Condition is sent
along with IC Address
Stop Condition is sent
Start Condition is sent
along with IC Address
Stop Condition is sent
Address is sent to the
C Interface
and R/W bit set to W
and R/W bit set to R
The desired Data is
Control Register
read from the IC
MC44S803
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