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XC2200 Derivatives
System Units (Vol. 1 of 2)
Startup Configuration and Bootstrap Loading
User’s Manual
10-27
V2.1, 2008-08
SCFG/BSL, V1.3
To summarize: the external host must send initialization frames (the content as above
defined) continuously until an acknowledge frame is received back from the XC2200
having the same message identifier as sent by the host in data bytes 2/3 from the
initialization frame, then the
begins.
Data Transmission Phase
In the data transmission phase, data frames are sent by the external host and received
by the XC2200. The data frames use the 11-bit data message identifier DMSGID that
has been sent with the initialization frame. Eight data bytes are transmitted with each
data frame. The first data byte is stored in PSRAM at E0’0000
H
. Consecutive data bytes
are stored at incrementing addresses.
Both communication partners evaluate the data message count DMSGC until the
requested number of CAN data frames has been transmitted. After the reception of the
last CAN data frame, the bootstrap loader finishes and executes the loaded code.
Timing Parameters
There are no general restrictions for CAN timings of the external host. During the
initialization phase the external host transmits initialization frames. If no acknowledge
frame is sent back within a certain time as defined in the external host (e.g. after a
dedicated number of initialization frame transmissions), the external host can decide that
the XC2200 is not able to establish the CAN boot communication link.
Table 10-12 CAN Bootstrap Loader Frames
Frame Type
Parameter
Description
Initialization
Frame
Identifier
11-bit, don’t care
DLC = 8
Data length code, 8 bytes within CAN frame
Data bytes 0/1
Baud rate detection pattern (5555
H
)
Data bytes 2/3
Acknowledge message identifier ACKID
(complete register contents)
Data bytes 4/5
Data message count DMSGC, 16-bit
Data bytes 6/7
Data message identifier DMSGID
(complete register contents)
Acknowledge
Frame
Identifier
Acknowledge message identifier ACKID as received
by data bytes [3:2] of the initialization frame
DLC = 4
Data length code, 4 bytes within CAN frame
Data bytes 0/1
Contents of bit-timing register
Data bytes 2/3
Copy of acknowledge identifier from initialization frame