mc68hc916y3 Freescale Semiconductor, Inc, mc68hc916y3 Datasheet - Page 193

• Manufacturer Part Number: mc68hc916y3
• Description: Mc68hc16y3 16 Bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

8.1 Flash EEPROM Control Block
MC68HC16Y3/916Y3
USER’S MANUAL
The flash EEPROM modules serve as nonvolatile, fast-access, electrically erasable
and programmable ROM-emulation memory. These modules are used only in the
MC68HC916Y3.
The MC68HC916Y3 contains a 96-Kbyte module. The 96-Kbytes is divided into 16-
Kbyte, 32-Kbyte, and 48-Kbyte arrays. The modules can contain program code (for ex-
ample, operating system kernels and standard subroutines) which must execute at
high speed or is frequently executed, or static data which is read frequently. The flash
EEPROM supports both byte and word reads. It is capable of responding to back-to-
back IMB accesses to provide two bus cycle (four system clock) access for aligned
long words. It can also be programmed to insert up to three wait states to accommo-
date migration from slower external development memory to onboard flash EEPROM
without the need for retiming the system.
The 16-Kbyte flash EEPROM array can begin on any 16-Kbyte boundary, the 48-
Kbyte array can begin on any 48-Kbyte boundary, and the 32-Kbyte array can begin
on any 32-Kbyte boundary. The three arrays can be configured to appear as a single
contiguous memory block, with the 16-Kbyte array immediately preceding or immedi-
ately following the 48- and 32-Kbyte arrays.
Pulling data bus pin DATA14 low during reset disables both the 16- , 48- and 32-Kbyte
flash EEPROM modules and places them in stop mode.
All of the flash EEPROM modules can be configured to generate bootstrap information
on system reset. Bootstrap information consists of the initial program counter and
stack pointer values for the CPU16.
The flash EEPROM and its control bits are erasable and programmable under soft-
ware control. Program/erase voltage must be supplied via external V
programmed in byte or word aligned fashion. Multiple word programming is not sup-
ported. The flash EEPROM modules support bulk erase only, and have a minimum
program-erase life of 100 cycles.
The flash EEPROM modules have hardware interlocks which protect stored data from
corruption by accidental enabling of the program/erase voltage to the flash EEPROM
arrays. With the hardware interlocks, inadvertent programming or erasure is highly un-
likely.
Each flash EEPROM module has a 32-byte control block with five registers to control
flash EEPROM operation: the flash EEPROM module configuration register
(FEE1MCR, FEE2MCR, FEE3MCR), the flash EEPROM test register (FEE1TST,
FEE2TST, FEE3TST), the flash EEPROM array base address registers (FEE1BAH,
FEE2BAH, FEE3BAH and FEE1BAL, FEE2BAL, FEE3BAL), and the flash EEPROM
control register (FEE1CTL, FEE2CTL, FEE3CTL).
SECTION 8FLASH EEPROM MODULE
Freescale Semiconductor, Inc.
For More Information On This Product,
FLASH EEPROM MODULE
Go to: www.freescale.com
FPE
pins. Data is
MOTOROLA
8-1