Honored ContributorHello,
What is the meaning of 5000 in alt_read_flash(fd, 0, dest, 5000)? I cannot understand the arguments inside alt_read_flash. I read a few articles and notes but still cannot get its meaning. pls help. thanks!
Honored Contributorint alt_read_flash( alt_flash_fd* fd,
int offset, void* dest_addr, int length ); In the "Using Flash Devices" section of the Nios II SW Developers Handbook. "A call to alt_read_flash() reads from the flash device with the handle fd, offset bytes from the beginning of the flash device. The function writes the data to location pointed to by dest_addr, and the amount of data read is length. For most flash devices, you can access the contents as standard memory, making it unnecessary to use alt_read_flash()."Honored Contributorhi... thanks for the reply. i am quite confused with "length". what does it mean by "amount of data read" which is "length"? is it in bytes or the number of data to be read? example, i am writing 1Mb of data to flash and want to read it out. so what should be the length for alt_write_flash and alt_read_flash?
thanks!Honored ContributorIt is in bytes.
Honored ContributorSo, it means, if my data is 1Mb, so the length is 1Mb?
Honored ContributorCorrect. You write however many bytes you would like to read out in that field. You can look at some of the memtest examples for their usage of it as well.
You do have to play nicely with the region size though if you are managing the file locations yourself. So, don't expect to write a partial block and not have the other contents of that block erased. But that is a whole other topic kinda.Honored ContributorHonored ContributorHi, mmTsuchi. I am transferring 1MB (1 Mega Byte) of data into flash. I am using alt_write_flash. So, what should be the length in alt_write_flash. pls help. I have been debugging the whole day but still cannot understand. Thanks!
Honored Contributor1048576, or 0x100000
Honored ContributorYes, i put that before but the return value for alt_write_flash is an error. cannot write.
Honored Contributormy code is here: http://www.alteraforum.com/forum/showthread.php?t=28345
