Specifications

FC protocol description
Developer’s Serial Bootloader, Rev. 13
Freescale Semiconductor 11
2.4.4 Erase command
The erase command (coded as ‘E’, $45) has only address field, length or data fields are not present. The
start address is a 2-byte field, MSB first. If the CRC capability of serial protocol is enabled, then the 16
bits(2 bytes) follows with CRC-CCITT checksum.
The MCU erases the address block where the specified address resides. The length of block to be erased
is equal to the erase-block size (typically depends on hardware).
After the MCU completes execution of the command, the ACK ($FC) character is sent to the PC. If the
CRC capability of serial protocol is enabled, then the 16 bits(2 bytes) follows with CRC-CCITT
checksum. The erase command’s minimum and maximum execution times are not specified.
Figure 10. Erase command
2.4.5 Write command
The write command (coded as ‘W’, $57) has both address and data fields. The address contains the first
address to be programmed. The first byte is the length followed by the number of bytes to be programmed.
The start address is a 2-byte field, MSB first and the length is a 1-byte field. If the CRC capability of serial
protocol is enabled, then the 16 bits(2 bytes) follows with CRC-CCITT checksum.
After the MCU completes execution of the command, the ACK ($FC) character is sent to the PC. If the
CRC capability of serial protocol is enabled, then the 16 bits(2 bytes) follows with CRC-CCITT
checksum. The write command’s minimum and maximum execution times are not specified.
Figure 11. Write command
2.4.6 Read command
The read command (coded as ‘R’, $52) has address and data fields. The address contains the first address
to be programmed; the single byte is the length of data to be read. The start address is a 2-byte field, MSB
first and the length is a 1-byte field. If the CRC capability of serial protocol is enabled, then the 16 bits(2
bytes) follows with CRC-CCITT checksum.
E ($45)
ACK
PC TO MCU COMMAND
MCU TO PC RESPONSE
START
ADDRESS
COMMAND EXECUTION
CRC
CRC
W ($57)
ACK
PC TO MCU COMMAND
MCU TO PC RESPONSE
BINARY DATA
LENGTH
START
ADDRESS
COMMAND EXECUTION
CRC
CRC