MC68HC705P6A Datasheet, PDF (86/130 Pages) Motorola, Inc – HCMOS Microcontroller Unit

EPROM
To program a byte of EPROM, manipulate the EPROG register as
follows:
1. Set the ELAT bit in the EPROG register.
2. Write the desired data to the desired EPROM address.
3. Set the EPGM bit in the EPROG register for the specified
programming time, tEPGM.
4. Clear the ELAT and EPGM bits in the EPROG register.
This sequence is also shown in the sample program listing in Table 10-1.
Table 10-1. EPROM Programming Routine
001C
0055
0700
0000
EPROG
DATA
EPROM
EPGM
EQU $1C
EQU $55
EQU $700
EQU $00
PROGRAMMING REG
DATA VALUE
A SAMPLE EPROM ADX
EPGM BIT IN EPROG REG
00D0
ORG $D0
00D0
00D2
00D4
00D6
00D9
00DB
00DD
00DF
A6 02
B7 1C
A6 55
C7 07 00
10 1C
AD 03
3F 1C
81
LDA #$04
STA EPROG
LDA #DATA
STA EPROM
BSET EPGM, EPROG
BSR DELAY
CLR EPROG
RTS
SET LAT BIT IN EPROG
DATA BYTE
WRITE IT TO EPROM LOC
TURN ON PGM VOLTAGE
WAIT 4 ms MINIMUM
CLR LAT AND PGM BITS
10.7 EPROM Bootloader
Three port pins are associated with bootloader control functions: PC3,
PC4, and PC6. Table 10-2 summarizes their functionality.
Table 10-2. Bootloader Control Pins
PC6 PC4 PC3
1
1
1
1
1
0
1
0
0
Mode
Program/verify
Verify only
Dump MCU EPROM to port A
Advance Information
86
EPROM
MC68HC705P6A — Rev. 2.0
MOTOROLA