The Erased State of a Flash cell

[#1]

Hello,

I'm working with infineon TC277TE controller and TASKING compiler.

As it is given in the user manaul that "The erased state of a Flash cell is logical ‘0’" . I'm following the same procedure to Erase PFlash are as given in the user manual , but after erase the state of flash cell is showing ASCII symbol '?' (as shown in below screen shot) .



Please help me to get logical '0' after erase.


- Thanks & Regards
Veeresh

[µC_Wrangler]

Veeresh Biradar wrote:
Hello,

I'm working with infineon TC277TE controller and TASKING compiler.

As it is given in the user manaul that "The erased state of a Flash cell is logical ‘0’" . I'm following the same procedure to Erase PFlash are as given in the user manual , but after erase the state of flash cell is showing ASCII symbol '?' (as shown in below screen shot) .



Please help me to get logical '0' after erase.

It is true that the erased state is logical 0 - however, a flash erase operation also erases the ECC bits, so any subsequent reads from that memory range will cause an ECC error. That's the reason the debugger shows '?' in the data dump window. As the user manual states:

As side effect of the all-0 error detection an erased Flash range can’t be read without ECC errors.

If you want to fill a memory range with 0, you need to erase it, and then write the range with 0s, which will generate a correct ECC.