MAX32665-MAX32668 User Guide
Maxim Integrated Page 136 of 457
7.2.4 Flash Write
Writes to a flash location are only successful if the targeted location is already in its erased state. Perform the following
steps to write to a flash memory instance:
1. If desired, enable flash controller interrupts by setting the FLCn_INTR.access_error_ie and FLCn_INTR.done_ie bits.
2. Read the FLCn_CTRL.busy bit until it returns 0.
3. Configure FLCn_CTRL.clkdiv to match the SYS_CLK frequency.
4. Set the FLCn_ADDR register to a valid target address. Reference Table 7-2.
5. Set FLCn_DATA3, FLCn_DATA2, FLCn_DATA1, and FLCn_DATA0 to the data to write. FLCn_DATA3 is the most
significant word and FLCn_DATA0 is the least significant word. Each word of the data to write follows the little-
endian format where the least significant byte of the word is stored at the lowest-numbered byte and the most
significant byte is stored at the highest-numbered byte.
6. Set FLCn_CTRL.unlock to 0x2 to unlock the flash instance.
7. Set FLCn_CTRL.write to 1. This field is automatically cleared by the Flash Controller when the write operation is
finished.
8. FLCn_INTR.done is set by hardware when the write completes and if an error occurred, the FLCn_INTR.access_fail
flag is set. These bits generate a flash IRQ if the interrupt enable bits are set.
9. Set FLCn_CTRL.unlock to any value other than 0x2 to re-lock the flash instance.
Note: Code execution can occur within the same flash instance as targeted programming.
7.2.5 Page Erase
CAUTION: Care must be taken to not erase the page from which application code is currently executing.
Perform the following to erase a page of a flash memory instance:
1. If desired, enable flash controller interrupts by setting the FLCn_INTR.access_error_ie and FLCn_INTR.done_ie bits.
2. Read the FLCn_CTRL.busy bit until it returns 0.
3. Configure FLCn_CLKDIV.clkdiv to match the SYS_CLK frequency.
4. Set the FLCn_ADDR register to an address within the target page to be erased. FLCn_ADDR[12:0] are ignored by
the Flash Controller to ensure the address is page aligned.
5. Set FLCn_CTRL.unlock to 0x2 to unlock the flash instance.
6. Set FLCn_CTRL.erase_code to 0x55 for page erase.
7. Set FLCn_CTRL.page_erase to 1 to start the page erase operation.
8. The FLCn_CTRL.busy bit is set by the flash controller while the page erase is in progress and the
FLCn_CTRL.page_erase and FLCn_CTRL.busy are cleared by the flash controller when the page erase is complete.
9. FLCn_INTR.done is set by hardware when the page erase completes and if an error occurred, the
FLCn_INTR.access_fail flag is set. These bits generate a flash IRQ if the interrupt enable bits are set.
10. Set FLCn_CTRL.unlock to any value other than 0x2 to re-lock the flash instance.
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