2.5.1 Flash-Self Programming Failing When Flash Read During Programming

If data are read from the Flash NRWW section while the Flash RWW section is being written to or erased (Flash Page Write or Flash Page Erase), the erase or write may fail. Instruction fetch from the Flash NRWW section does not affect erase or write operation to the Flash RWW section.

Work Around

Alternative 1: RWW functionality not needed

Do not use flash self-programming when executing from the NRWW section

Alternative 2: RWW functionality needed

Enable BOD in continuous mode (in FUSE.BODCFG, set bitfield LVL to BODLEVEL1 or higher and bitfield ACTIVE to 0x3)
Do not use the Flash Page Erase and Page Write operation (writing the CMD bitfield in NVMCTRL.CTRLA to 0x05). Execute Flash Page Erase and Flash Page Write as two separate operations instead.

Affected Silicon Revisions


Rev. A0
X