
The Kinetis Flashloader supports 400 kbps as the SPI baud rate.
The SPI peripheral uses the following bus attributes:
• Clock Phase = 1 (Second Edge)
• Clock Polarity = 1 (Active Low)
Because the SPI peripheral serves as a SPI slave device, each transfer should be started
by the host, and each outgoing packet should be fetched by the host.
The transfer on SPI is slightly different from I2C:
• Host will receive 1 byte after it sends out any byte.
• Received bytes should be ignored when host is sending out bytes to target
• Host starts reading bytes by sending 0x00s to target
• The byte 0x00 will be sent as response to host if target is under the following
conditions:
• Processing incoming packet
• Preparing outgoing data
• Received invalid data
The SPI bus configuration is:
• Phase = 1; data is sampled on rising edges
• Polarity = 1; idle is high
• MSB is transmitted first
For any transfer where the target does not have actual data to send, the target (slave) is
responsible for ensuring that 0x00 bytes will be returned to the host (master). The host
uses framing packets to identify real data and not "dummy" 0x00 bytes (which do not
have framing packets).
The following flowcharts demonstrate how the host reads a ping response, an ACK and a
command response from target via SPI.
Fetch
Ping response
Yes
Yes
End
Report Error
No
No
0x5A
received?
0xA7
received?
Send 0x00 to
shift out 1 byte
from target
Send 0x00 to
shift out 1 byte
from target
Send 0x00s to shift
out leftover bytes
of ping response
Figure 13-21. Host reads ping packet from target via SPI
Peripherals Supported
K22F Sub-Family Reference Manual, Rev. 4, 08/2016
330
NXP Semiconductors
Summary of Contents for K22F series
Page 2: ...K22F Sub Family Reference Manual Rev 4 08 2016 2 NXP Semiconductors...
Page 168: ...Module clocks K22F Sub Family Reference Manual Rev 4 08 2016 168 NXP Semiconductors...
Page 258: ...Functional description K22F Sub Family Reference Manual Rev 4 08 2016 258 NXP Semiconductors...
Page 292: ...Functional description K22F Sub Family Reference Manual Rev 4 08 2016 292 NXP Semiconductors...
Page 398: ...Functional description K22F Sub Family Reference Manual Rev 4 08 2016 398 NXP Semiconductors...
Page 750: ...Functional description K22F Sub Family Reference Manual Rev 4 08 2016 750 NXP Semiconductors...
Page 816: ...Application information K22F Sub Family Reference Manual Rev 4 08 2016 816 NXP Semiconductors...
Page 890: ...Application information K22F Sub Family Reference Manual Rev 4 08 2016 890 NXP Semiconductors...
Page 1302: ...Application information K22F Sub Family Reference Manual Rev 4 08 2016 1302 NXP Semiconductors...
Page 1374: ...Functional description K22F Sub Family Reference Manual Rev 4 08 2016 1374 NXP Semiconductors...