5.5 CSEQ Write Flash Request

The following are the two parameters to consider for the CSEQ write Flash Request:
  • Offset of the firmware data to send
  • Firmware data

The maximum limit for the firmware data is 240 bytes. After Flashing the firmware by the BM78 or the RN4678 module, the BM78 or the RN4678 module returns an CSEQ Event. The CSEQ Event consists of the firmware offset and the firmware data length.

Table 5-6. Write Flash Request Format

CSEQ_DEL

CSEQ_BEGIN

CSEQ_

OPCODE

CSEQ_

OFFSET

CSEQ_DATA

CSEQ_CRC

CSEQ_DEL

CSEQ_END

Byte Number

0

1

2

3 - 4

5-n

n+1-n+2

n+3

n+4

Size (bytes)

1

1

1

2

n

2

1

1

Value

0x3C

0x66

0x45

0xXXXX

0xXXXX…

0xXXXX

0x3C

0x5A

The following figure illustrates the Write Flash Request Sequence example data. In BM78 Module DFU Demo with SAMG55 Xplained Pro Evaluation Kit, the firmware data length is set to 32.
Figure 5-12. Write Flash Request Sequence Example Data
The following figure illustrates the Write Flash Request Event example data and the CSEQ Response. In the CSEQ event, the 0x0000 is the previous firmware data offset and 0x20 is the data length of the firmware chunk; see the following figure.
Figure 5-13. Write Flash Request Event Example Data