XC886/888CLM
Bootstrap Loader
User’s Manual
18-16
V1.3, 2010-02
Bootstrap Loader, V1.0
18.1.3
Bootstrap Loader via LIN
Standard LIN protocol can support a maximum baud rate of 20 kHz. However, the
XC886/888L device has an enhanced feature which supports a baud rate of up to
115.2 kHz. LIN BSL is implemented to support the baud rate of 20 kHz and below using
standard LIN protocol, while Fast LIN BSL is introduced to support the baud rate of
20 kHz to 115.2 kHz via a single-wire UART using UART protocol. See
.
LIN BSL supports Fast Programming through Mode 0, Mode 2 or Mode 8 with the
selection of Fast Programming Option. Refer to
Features of LIN BSL are:
•
Re-synchronization of the transfer speed (baud rate) of the communication partner
upon receiving every LIN frame
•
Use of Diagnostic Frame (Master Request and Slave Response)
•
User-preloaded NAD stored in uppermost P-Flash Bank Pair. (Default Broadcast
NAD used if value not present or valid)
•
Save LIN frame into XRAM and jump to User Mode if first frame received is an invalid
LIN Frame
•
Programming and LIN Checksum supported
•
Fast LIN BSL using BSL Mode protocol on single-wire UART (LIN)
Re-synchronization and setup of baud rate (Phase I) are always performed prior to the
entry of Phase II and III. Thus different baud rates can be supported. Phase II is entered
when its Master Request Header is received, otherwise Phase III is entered (Slave
Response Header). The Master Request Header has a Protected ID of 3C
H
while the
Slave Response Header has a Protected ID of 7D
H
. The microcontroller responds to the
host only after a Slave Response Header is received. The Command and Response LIN
frames are identified as Diagnostic LIN frame which has a standard 8 data byte structure
(instead of 2 or 4).
Upon entering LIN BSL, a connection is established and the transfer speed (baud rate)
of the serial communication partner (host) is automatically synchronized in the following
steps:
•
STEP 1: Initialize interface for reception and timer for baud rate measurement
•
STEP 2: Wait for an incoming LIN frame from the host
•
STEP 3: Synchronize the baud rate to the host
•
STEP 4: Enter Phase II (for Master Request Frame) or
•
Phase III (for Slave Response Frame)
Note: Re-synchronization and setup of baud rate are always done for
every
Master
Request Header or Slave Response Header LIN frame.
A Header LIN frame consists of the:
•
Synch (SYN) Break (13 bit times low)
•
Synch (SYN) byte (55
H
)
*