SPRUJ79 November 2024 F29H850TU
The CAN bootloader asynchronously transfers code from CAN-A to internal memory as shown in Figure 4-12. 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 bit timing registers are programmed in such a way that a 100kbps bit rate is achieved with a 20MHz external oscillator, as shown in Table 4-22.
OSCCLK | SYSCLK | Bit Rate |
---|---|---|
20MHz | 200MHz | 100kbps |
25MHz | 200MHz | 100kbps |
The bootROM configures and locks PLL at 200MHz and also configures CAN bit clock at 20MHz using XTAL oscillator as clock source if detected; otherwise, defaults to INTOSC2.
Mailbox 1 is programmed with a standard MSGID of 0x1 for bootloader communication. The CAN host transmits only two 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.