AN2430 Datasheet, PDF (6/24 Pages) STMicroelectronics – STR75x SystemMemory boot mode

General description
AN2430
1.4.2
Read Memory command
Description:
This command allows the user to read the memory (RAM, Flash and registers).
When the bootloader receives the Read Memory command, it transmits the ACK byte.
After the transmission of the ACK byte, the bootloader waits for an address (4 bytes, byte 1
is the MSB and byte 4 is LSB of the address), checks this address, if the address is valid, it
transmits an ACK byte otherwise it transmits a NACK byte (0x3F) and exits from the
command.
When the address is valid, the bootloader waits for the number of bytes to be transmitted (N
bytes) and then returns to the user the needed data ((N + 1) bytes) starting from the
received address.
Figure 2. Read memory flowchart
Start RM
Received byte
No
== 0x11?
Send ACK byte
Receive the start address (4 bytes)
No
Valid Address?
Send NACK byte
Send ACK byte
Receive the number of bytes to be read
(1 byte)
Send data to the user
End of RM
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