NXP Semiconductors K32 L2A Series, Reference Manual, Page: 262 / 1379

• Data phases may be aborted by the host sending the final
Generic Response early with a status of
kStatus_AbortDataPhase. The sending side may abort the
data phase early by sending a zero-length data packet.
• The final Generic Response packet sent after the data
phase includes the status for the entire operation.
14.3.7 Bootloader Packet Types
The Kinetis Bootloader device works in slave mode. All data communication is initiated
by a host, which is either a PC or an embedded host (note that QuadSPI is treated like a
storage device, like flash). The Kinetis Bootloader device is the target, which receives a
command or data packet. All data communication between host and target is packetized.
NOTE
The term "target" refers to the "Kinetis Bootloader device."
There are 6 types of packets used in the device:
• Ping packet
• Ping Response packet
• Framing packet
• Command packet
• Data packet
• Response packet
All fields in the packets are in little-endian byte order.
14.3.7.1 Ping packet
The Ping packet is the first packet sent from a host to the target (Kinetis Bootloader), to
establish a connection on a selected peripheral. For a LPUART peripheral, the Ping
packet is used to determine the baudrate. A Ping packet must be sent before any other
communications. In response to a Ping packet, the target sends a Ping Response packet.
Table 14-6. Ping Packet Format
Byte # Value Name
0 0x5A start byte
1 0xA6 ping
Functional Description
K32 L2A Reference Manual, Rev. 2, 01/2020
262 NXP Semiconductors