MC68711E20CFNE3 Datasheet, PDF (209/242 Pages) –

Listing 1. MCU-to-MCU Duplicator Program
27
**************************************************
28
*
29 B600 7F103D BEGIN
CLR INIT
Moves Registers to $0000-3F
30 B603 8604
LDAA #$04
Pattern for DWOM off, no SPI
31 B605 9728
STAA SPCR
Turns off DWOM in EVBU MCU
32 B607 8680
LDAA #RESET
33 B609 9704
STAA PORTB
Release reset to target MCU
34 B60B 132E20FC WT4BRK
BRCLR SCSR RDRF WT4BRK Loop till char received
35 B60F 86FF
LDAA #$FF
Leading char for bootload ...
36 B611 972F
STAA SCDR
to target MCU
37 B613 CEB675
LDX #BLPROG
Point at program for target
38 B616 8D53
BLLOOP
BSR SEND1
Bootload to target
39 B618 8CB67D
CPX #ENDBPR
Past end ?
40 B61B 26F9
BNE BLLOOP
Continue till all sent
41
*****
42
* Delay for about 4 char times to allow boot related
43
* SCI communications to finish before clearing
44
* Rx related flags
45 B61D CE06A7
LDX #1703
# of 6 cyc loops
46 B620 09
DLYLP
DEX
[3]
47 B621 26FD
BNE DLYLP
[3] Total loop time = 6 cyc
48 B623 962E
LDAA SCSR
Read status (RDRF will be set)
49 B625 962F
LDAA SCDR
Read SCI data reg to clear RDRF
50
*****
51
* Now wait for character from target to indicate it's ready for
52
* data to be programmed into EPROM
53 B627 132E20FC WT4FF
BRCLR SCSR RDRF WT4FF Wait for RDRF
54 B62B 962F
LDAA SCDR
Clear RDRF, don't need data
55 B62D CED000
LDX #EPSTRT
Point at start of EPROM
56
* Handle turn-on of Vpp
57 B630 18CE523D WT4VPP
LDY #21053
Delay counter (about 200ms)
58 B634 150402
BCLR PORTB RED
Turn off RED LED
59 B637 960A
DLYLP2
LDAA PORTE
[3] Wait for Vpp to be ON
60 B639 2AF5
BPL WT4VPP
[3] Vpp sense is on port E MSB
61 B63B 140402
BSET PORTB RED
[6] Turn on RED LED
62 B63E 1809
DEY
[4]
63 B640 26F5
BNE DLYLP2
[3] Total loop time = 19 cyc
64
* Vpp has been stable for 200ms
65
66 B642 18CED000
LDY #EPSTRT
X=Tx pointer, Y=verify pointer
67 B646 8D23
BSR SEND1
Send first data to target
68 B648 8C0000 DATALP
CPX #0
X points at $0000 after last
69 B64B 2702
BEQ VERF
Skip send if no more
70 B64D 8D1C
BSR SEND1
Send another data char
71 B64F 132E20FC VERF
BRCLR SCSR RDRF VERF Wait for Rx ready
72 B653 962F
LDAA SCDR
Get char and clr RDRF
73 B655 18A100
CMPA 0,Y
Does char verify ?
74 B658 2705
BEQ VERFOK
Skip error if OK
75 B65A 150403
BCLR PORTB (RED+GREEN) Turn off LEDs
76 B65D 2007
BRA DUNPRG
Done (programming failed)
77 B65F
78 B65F 1808
VERFOK
INY
Advance verify pointer
79 B661 26E5
BNE DATALP
Continue till all done
80 B663
81 B663 140401
BSET PORTB GREEN
Grn LED ON
M68HC11 Bootstrap Mode, Rev. 1.1
Freescale Semiconductor
209