Rainbow Electronics AT88SA100S - Manual (Page 15)

AT88SA100S [ Preliminary]
15
8558A–SMEM–03/09
4.3. BurnFuse
Burns one of the 88 user accessible fuse bits.
The power supply pin must meet the V
BLOW
specification in order to burn fuses reliably. If the voltage is too low then the
actual fuse blow will not be attempted and the chip will return the error code. If the watchdog timer is within t
EXEC_FUSE
of
its expiration, this command will also be aborted and return an error.
The values in fuses #88-127 are reserved for the MfrID and SerialNumber and cannot be blown via this command. All
addresses above 0x4C (87) will result in an error.
Fuses, with the exception of those initialized by Atmel, have a value of 1 on shipment from the Atmel factory and
transition to a 0 when they are burned.
Fuse bits #0 through #7 of the fuse array are word lock bits. Burning one of these has the effect of locking the
corresponding 16 bit word within Fuse. Bit 0 locks fuses 0-15, bit 1 locks fuses 16-31 and so on. If bit 0 is burned, then
the value of the lock bits can no longer be changed. The values of lock bits 6 & 7 are ignored by the chip.
There is a very small interval during t
EXEC_FUSE
when the fuse element is actually being blown. The power supply must
not be removed during this interval, or the fuse may end up in a state where it reads as un-blown but cannot be burned.
Table 13. Input Parameters
Name Size Notes
Opcode BURNFUSE 1 0x04
Param1 Address 1 Must be 0x00 00
Param2 Zero 2 Should be all 0’s
Data – 0
Table 14. Output Parameters
Name Size Notes
Success 1 Upon successful completion, a value of 0 will be returned by the device.