MC68HC705MC4 Datasheet, PDF (19/99 Pages) Motorola, Inc – Microcontrollers

MC68HC705MC4 Specification Rev. 1.5
BOOT
INITIALIZE I/O PORTS
PUT RAMSUB IN RAM
PC3=1
YES
NO
PC2=1 ^YES
DUMP EPROM
NO
DDRA=OUTPUT
BUMP COUNT TO $100
GET BYTE START @ $100
PUT BYTE ON PORT A
JSR NEXTADDR
YES
END ADDRESS
($0FFF)
NO
YES PC0=1
NO
(SYNC)
WAIT
YES
PC1=0
NO
JUMP TO RAM
MAYPRG
PC2=1
YES
PRG/VERF
YES
NO
PC0=1
NO
GATE STRESS
DRAIN STRESS
WAIT
BUMP COUNT TO $100
GET BYTE FROM PORT A
PROGRAM BYTE
JSR NEXTADDR
END ADDR
NO
($0FFF)
YES
VERIFY
CHANGE INSTRUCTION
FROM STA TO EOR
INC COUNT TO $100
START ADDR <- $100
GET BYTE FROM PORT A
JSR RAMSUB
NO _COMPARE
YES
JSR NEXTADDR
END ADDRESS
NO
($0FFF)
YES
VERIFY LED ON
WAIT
Figure 2-3: Bootloader Flowchart
MOTOROLA
Page 10
Section 2: Operating Modes