Bootloader Features
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SPRUI07–March 2020
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Boot ROM
2.2.22 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 the following pins:
• CANRXA on GPIO30
• CANTXA on GPIO31
Figure 2-37. Overview of eCAN-A Bootloader Operation
The bit-timing registers are programmed in such a way that a valid bit-rate is achieved for different
XCLKIN values as shown in Table 2-15.
Table 2-15. Bit-Rate Values for Different XCLKIN Values
XCLKIN SYSCLKOUT Bit Rate
30 MHz 15 MHz 500 kbps
15 MHz 7.5 MHz 250 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 15, 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 Table 2-16.
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