 English |
|
|
|
|
|
|
|
| MC68HC05L16 Datasheet, PDF (137/146 Pages) Freescale Semiconductor, Inc – Microcontrollers | |||
| |||
| ◁ |
Boot ROM
A.9 Boot ROM
Boot ROM is 496 bytes of mask ROM positioned at $FE00â$FFEF. This ROM contains bootstrap loader
programs and reset/interrupt vectors in the bootstrap mode. The bootstrap loader programs include:
⢠EPROM programming and verification
⢠Dumping EPROM contents
⢠Loading programs into the internal RAM
⢠Executing programs in the internal RAM
A.10 EPROM
The 16-Kbyte EPROM is positioned at $1000â$4FFF, and the additional 16 bytes of EPROM are located
at $FFF0â$FFFF for user vectors. The erased state of EPROM is read as $FF and EPROM power is
supplied from the VPP pin and the VDD pin.
The program control register (PCR) is provided for EPROM programming and testing. The functions of
EPROM depend on the device mode.
In user mode, ELAT and PGM bits in the PCR are available for user programming, and the remaining test
bits become read-only bits. The VPP pin should be tied to 5 volts or programming voltage.
A.10.1 Programming Sequence
To program the MC68HC705L16, execute this sequence:
⢠Set the ELAT bit
⢠Write the data to the address to be programmed
⢠Set the PGM bit
⢠Delay for an appropriate amount of time
⢠Clear the PGM bit and the ELAT bit
Clearing the PGM bit and the ELAT bit may be done on a single CPU write.
NOTE
It is important to remember that an external programming voltage must be
applied to the VPP pin while programming, but it should be equal to VDD
during normal operations.
MC68HC05L16 ⢠MC68HC705L16 Data Sheet, Rev. 4.1
Freescale Semiconductor
137
|
▷ |
German
Russian
Spanish
Italian
Polish
Chinese
Japanese
Korean
French
Portuguese