MC68HC705P9 Datasheet, PDF (39/160 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Freescale Semiconductor, Inc.
Memory
EPROM/OTPROM
Take the following steps to program a byte of EPROM/OTPROM:
1. Apply 16.5 V to the IRQ/V_PP pin.
2. Set the LATCH bit.
3. Write to any EPROM/OTPROM address.
4. Set the EPGM bit for a time, t_EPGM, to apply the programming
voltage.
5. Clear the LATCH bit.
3.6.1.2 Bootloader ROM
The bootloader ROM, located at addresses $1F00–$1FEF, contains
routines for copying an external EPROM to the on-chip
EPROM/OTPROM.
The bootloader copies to the following EPROM/OTPROM addresses:
• $0020–$004F
• $0100–$0900
• $1FF0–$1FFF
The addresses of the code in the external EPROM must match the
MC68HC705P9 addresses. The bootloader ignores all other addresses.
Figure 3-4 shows the circuit for downloading to the on-chip
EPROM/OTPROM from a 2764 EPROM. The bootloader circuit includes
an external 12-bit counter to address the external EPROM. Operation is
fastest when unused external EPROM addresses contain $00. The
bootloader function begins when a rising edge occurs on the RESETpin
while the V_PP voltage is on the IRQ/V_PP pin, and the PD7/TCAP pin is at
logic one.
MC68HC705P9 — Rev. 4.0
MOTOROLA
Memory
For More Information On This Product,
Go to: www.freescale.com
Technical Data
39