MC68HC912BL16 Datasheet, PDF (42/128 Pages) Freescale Semiconductor, Inc – 16-Bit Microcontroller

Freescale Semiconductor, Inc.
7.6 Programming the Flash EEPROM
Programming the Flash EEPROM is accomplished by the following sequence. The V_FP pin voltage
must be at the proper level prior to executing step 4 the first time.
1. Apply program/erase voltage to the V_FP pin.
2. Clear ERAS and set the LAT bit in the FEECTL register to establish program mode and enable
programming address and data latches.
3. Write data to a valid address. The address and data is latched. If BOOTP is asserted, an at-
tempt to program an address in the boot block will be ignored.
4. Apply programming voltage by setting ENPE.
5. Delay for one programming pulse (t_PPULSE).
6. Remove programming voltage by clearing ENPE.
7. Delay while high voltage is turning off (t_VPROG).
8. Read the address location to verify that it has been programmed
• If the location is not programmed, repeat steps 4 through 7 until the location is programmed
or until the specified maximum number of program pulses has been reached (n_PP)
• If the location is programmed, repeat the same number of pulses as required to program the
location. This provides 100% program margin.
9. Read the address location to verify that it remains programmed.
10. Clear LAT.
11. If there are more locations to program, repeat steps 2 through 10.
12. Turn off V_FP (reduce voltage on V_FP pin to V_DD).
The flowchart in Figure 7 demonstrates the recommended programming sequence.
MC68HC912BL16
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