MC68HC705C9A Datasheet, PDF (113/118 Pages) Motorola, Inc – Microcontrollers

Appendix A
EPROM Programming
A.1 Introduction
This section describes programming of the EPROM.
A.2 Bootloader Mode
RESET
Table A-1. Operating Modes
IRQ
TCAP
V_SS to V_DD
V_TST
V_SS to V_DD
V_DD
Mode
User
Bootloader
Bootloader mode is entered upon the rising edge of RESET if the IRQ is at V_TST and the TCAP pin is at
logic one. The bootloader code resides in the ROM from $3F00 to $3FEF. This program handles copying
of user code from an external EPROM into the on-chip EPROM. The bootload function does not have to
be done from an external EPROM, but it may be done from a host.
The user code must be a one-to-one correspondence with the internal EPROM addresses.
A.3 Bootloader Functions
Three pins are used to select various bootloader functions: PD5, PD4, and PD3. Two other pins, PC6 and
PC7, are used to drive the PROG LED and the VERF LED, respectively. The programming modes are
shown in Table A-2.
Table A-2. Bootloader Functions
PD5
PD4
PD3
Mode
0
0
0
Program/verify
0
0
1
Verify only
0
1
0
Load RAM and execute
1
X
X
Secure
MC68HC05C9A Advance Information Data Sheet, Rev. 4.1
Freescale Semiconductor
113