JN5148 NXP Semiconductors, JN5148 Datasheet - Page 37

• Manufacturer Part Number: JN5148
• Description: The JN5148 is an ultra low power, high performance MCU combined with an IEEE802
• Manufacturer: NXP Semiconductors

sent from a slave, it should perform transmit using dummy data. An interrupt can be generated when the transaction
has completed or alternatively the interface can be polled.
If a slave device wishes to signal the JN5148 indicating that it has data to provide, it may be connected to one of the
DIO pins that can be enabled as an interrupt.
Figure 25 shows a complex SPI transfer, reading data from a FLASH device, that can be achieved using the SPI
master interface. The slave select line must stay low for many separate SPI accesses, and therefore manual slave
select mode must be used. The required slave select can then be asserted (active low) at the start of the transfer. A
sequence 8 and 32 bit transfers can be used to issue the command and address to the FLASH device and then to
read data back. Finally, the slave select can be deselected to end the transaction.
© NXP Laboratories UK 2011
SPIMOSI
SPIMISO
SPIMOSI
SPIMISO
SPISEL
SPICLK
SPISEL
SPICLK
Figure 25: Example SPI Waveforms – Reading from FLASH device using Mode 0
MSB
0
7
0
1
6
1
2
5
2
Instruction (0x03)
3
Byte 1
4
3
4
JN-DS-JN5148-001 1v7
3
4
Read Data Bytes Transaction(s) 1-N
5
2
5
value unused by peripherals
Instruction Transaction
6
1
6
7
0
7
MSB
MSB
8
23
7
8
Byte 2
9
22
6
9
10
21
5
10
24-bit Address
3
3
28
Byte N
2
2
29
1
1
30
LSB
8N-1
0
0
31
37