2.2.20 eCAN Boot Function
The eCAN bootloader asynchronously transfers code from eCAN-A to internal memory. The host can be any
CAN node. The communication is first done with 11-bit standard identifiers (with a MSGID of 0x1) using two
bytes per data frame. The host can download a kernel to reconfigure the eCAN if higher data throughput is
desired.
The eCAN-A loader uses following pins:
• CANRXA on GPIO30
• CANTXA on GPIO31
28x
28x
CAN
host
CANbus
Figure 2-27. Overview of eCAN-A bootloader Operation
The bit-timing registers are programmed in such a way that a valid bit-rate is achieved for a 10 MHz internal
oscillator frequency as shown in
Table 2-14. Bit-Rate Value for Internal Oscillators
OSCCLK
SYSCLKOUT
Bit Rate
10 MHz
10 MHz
100 kbps
The SYSCLKOUT values shown are the reset values with the default PLL setting. The BRP
reg
and bit-time
values are hard-coded to 1 and 25, respectively.
Mailbox 1 is programmed with a standard MSGID of 0x1 for boot-loader communication. The CAN host should
transmit only 2 bytes at a time, LSB first and MSB next. For example, to transmit the word 0x08AA to the device,
transmit AA first, followed by 08. The program flow of the CAN bootloader is identical to the SCI bootloader. The
data sequence for the CAN bootloader is shown in
Boot ROM
SPRUH18I – JANUARY 2011 – REVISED JUNE 2022
TMS320x2806x Microcontrollers
233
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Содержание TMS320 2806 Series
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