OM6274 NXP Semiconductors, OM6274 Datasheet - Page 6

• Manufacturer Part Number: OM6274
• Description: Interface Modules & Development Tools I2C to SPI Master Bridge Demoboard
• Manufacturer: NXP Semiconductors

Specifications of OM6274

• Interface Type: I2C, SPI
• Data Bus Width: 8 bit
• For Use With/related Products: SC18IS602IPW
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

NXP Semiconductors
SC18IS602_602B_603_4
Product data sheet
7.1.4 Read from buffer
the Function ID. There is no restriction on the number or combination of Slave Selects that
can be enabled for an SPI message. If more than one SSn pin is enabled at one time, the
user should be aware of possible contention on the data outputs of the SPI slave devices.
Table 3.
[1]
[2]
The data on the SPI port will contain the same information as the I
the slave address and Function ID. For example, if the message shown in
transmitted on the I
The SC18IS602/602B/603 counts the number of data bytes sent to the I
will automatically send this same number of bytes to the SPI bus. As the data is
transmitted from the MOSI pin, it is also read from the MISO pin and saved in the data
buffer. Therefore, the old data in the buffer is overwritten. The data in the buffer can then
be read back.
If the data from the SPI bus needs to be returned to the I
be completed by reading the data buffer.
A read from the data buffer requires no Function ID. The slave address with the R/W bit
set to a ‘1’ will cause the SC18IS602/602B/603 to send the buffer contents to the I
master. The buffer contents are not modified during the read process.
A typical write and read from an SPI EEPROM is shown in
Fig 7.
Fig 8.
Fig 9.
write to buffer
SS3 does not exist in the SC18IS603.
SS2 does not exist in the SC18IS602 and SC18IS603. Only SC18IS602B supports this function.
S
7
0
SLAVE ADDRESS
I
SPI message
Read from buffer
2
S
Function ID 01h to 0Fh
C-bus message
SLAVE ADDRESS
6
0
2
C-bus, the SPI bus will send the message shown in
Rev. 04 — 11 March 2008
W
A
5
0
SPI data
FUNCTION
R
DATA 1
A
ID
DATA 1
4
0
A
Section 8
DATA 1
SC18IS602/602B/603
A
SS3
3
gives an example of an SPI read.
[1]
DATA n
A
002aac451
2
C-bus master, the process must
SS2
Section
A
2
[2]
DATA n
2
C-bus data, but without
I
8.
A
2
C-bus to SPI bridge
SS1
© NXP B.V. 2008. All rights reserved.
2
1
DATA n
Figure
002aac449
C-bus port and
NA
Figure 7
P
002aac448
8.
A
SS0
2
C-bus
is
0
6 of 25
P