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Discussion Groups | M68HC11 | Student Need Help

Technical discussions about Freescale Microcontrollers: M68HC11. (Freescale Semiconductor is a Subsidiary of Motorola).

Student Need Help - indran19 - Oct 24 22:01:00 2004


hi friends..
my name is Indran..
i am from Malaysia..
i am doing final year BE(Mechatronics)..
currently i am doing a robot as my final year project..
i am using MC68HC11..
i am using expanded mode for this project...
as i am still inexperienced using this mode i need help from u..
hope u will help me..

here is my question...

1)The Circuit:
i am using a basic expanded mode circuit which has a demultiplexer
and NAND gates..i will use EPROM or EEPROM as the external memory..
i got this circuit from motorola manual..
Is there any problem with this circuit?Do i need to do any
modification to the circuit?Please let me know especially from those
who have tried the circut...

2)Memory:
i have intended to use 64 Kb EPROM or EEPROM.but i dunno how to load
the program inside the memory..Should i use serial communication
method?
or should i burn the progrmme inside EPROM and then connect it with
microcontroller?which is the better way?

3)Software needed:
what software should i use to load the program inside EPROM.please
recommend me the software?

4)i intended to program the robot using C language.what software
should i use so that the microcontroller can understand the
coding.Can i use Interactive C?please help me in this matter...

5)other precaution:
as i am just a beginner,please advise on some aspect on expanded mode
which i should be careful..what are the important thing i should
consider?where the problem normally happen?circuit or software?

6)Last Question:
this question may sound silly.but can the microcontroller really can
access the program inside the EPROM?i am quite confused on the method
of operation of expanded mode..so,if anyone who have use the expanded
mode,please help me...

I really need help from u...
i hope i can get the info i want..
thanx everyone who take time to read this...
and a million thanx for those who reply to me..
thanx a lot..
i am looking forward for a reply as soon as possible..






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Re: Student Need Help - Author Unknown - Oct 24 22:20:00 2004

If you look at the schematic of the tech arts microstamp
(technologicalarts.com) you will see how to operate in expanded mode. Expanded mode is explained
in detail in the hc11 manual. When the processor resets, it reads the moda
and modb pins. One of the 4 combinations is expanded mode. One of the io ports
is used for data and address lines, and another 8 bit port is used for the
hi address lines. The 8 bit latch is used to grab the lo 8 address bits. [Non-text portions of this message have been removed]



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Re: Student Need Help - John Beatty - Oct 25 7:42:00 2004

Hi Indran

--- indran19 <> wrote: (snipped) > 1)The Circuit: Bob Gardner has replied.

> 2)Memory:
> i have intended to use 64 Kb EPROM or EEPROM.but i
> dunno how to load
> the program inside the memory..Should i use serial
> communication
> method?
> or should i burn the progrmme inside EPROM and then
> connect it with
> microcontroller?which is the better way? Have you considered battery-backed CMOS RAM for you
external memory? It is quicker (and easier) to
program, is infintely re-programmable and probably
only a little more expensive. > 3)Software needed:
> what software should i use to load the program
> inside EPROM.please
> recommend me the software? If you do use EPROM external memory, you may find that
you need a separate programmer.

> 4)i intended to program the robot using C
> language.what software
> should i use so that the microcontroller can
> understand the
> coding.Can i use Interactive C?please help me in
> this matter... I'm sure you can use 'C' - I'll leave comments on this
to others

> 5)other precaution:
> as i am just a beginner,please advise on some aspect
> on expanded mode
> which i should be careful..what are the important
> thing i should
> consider?where the problem normally happen?circuit
> or software? If you make the circuit carefully, and double check
all your connections you should have no problem. Use
de-coupling capacitors close to the supply pins of
every chip. I recommend that you also read Freescale
application notes on the design and layout of the
crystal oscillator section of your board - they can
occasionally be tricky.

> 6)Last Question:
> this question may sound silly.but can the
> microcontroller really can
> access the program inside the EPROM?i am quite
> confused on the method
> of operation of expanded mode..so,if anyone who have
> use the expanded
> mode,please help me... Certainly. Study the sections in the MCU manual on the
mode control pins MODA and MODB. You don't say which
particular chip you wish to use, but if you go with
the F1, then you don't even need to de-multiplex the
low-order address/data signal on Port C. You can
thereby simplify your external circuitry
___________________________________________________________ALL-NEW Yahoo! Messenger - all new features - even more fun! http://uk.messenger.yahoo.com


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Re: Student Need Help - bart homerson - Oct 25 15:19:00 2004

I will agree with all of this. Yes, You can write the program in C. As Bob mentioned, Technological Arts has a great array of information, downloads, etc. http://www.technologicalarts.com . They have a C-compiler. I personally write everything in assembly and then use the AS11 compiler. When I download the program to the EEPROM, I use the simple Batch file that Technoloigical Arts provides with the starter kit. It may be difficult to find, but downloading the starter kit programs for the MicroCore11 would be a great start for you. I suggest using EEPROM and programming the device in the circuit this is always handy. Remember, you will need some RAM as well, and since the MC68HC11 can only address 64K, you will have a problem here. try 32k for the EEPROM, and 32K for the RAM. I have not seen the schematic you are writing about, so maybe they have a way, such as paging, so that you can address more locations. This seems a bit advanced in my opinion, so take it one step at a
time. If you get stuck on something, leave it alone for a while, then come back to it when your mind is clear; sometimes the most obvious problems are solved this way. Best wishes.

LF

John Beatty <> wrote:
Hi Indran

--- indran19 <> wrote: (snipped) > 1)The Circuit: Bob Gardner has replied.

> 2)Memory:
> i have intended to use 64 Kb EPROM or EEPROM.but i
> dunno how to load
> the program inside the memory..Should i use serial
> communication
> method?
> or should i burn the progrmme inside EPROM and then
> connect it with
> microcontroller?which is the better way? Have you considered battery-backed CMOS RAM for you
external memory? It is quicker (and easier) to
program, is infintely re-programmable and probably
only a little more expensive. > 3)Software needed:
> what software should i use to load the program
> inside EPROM.please
> recommend me the software? If you do use EPROM external memory, you may find that
you need a separate programmer.

> 4)i intended to program the robot using C
> language.what software
> should i use so that the microcontroller can
> understand the
> coding.Can i use Interactive C?please help me in
> this matter... I'm sure you can use 'C' - I'll leave comments on this
to others

> 5)other precaution:
> as i am just a beginner,please advise on some aspect
> on expanded mode
> which i should be careful..what are the important
> thing i should
> consider?where the problem normally happen?circuit
> or software? If you make the circuit carefully, and double check
all your connections you should have no problem. Use
de-coupling capacitors close to the supply pins of
every chip. I recommend that you also read Freescale
application notes on the design and layout of the
crystal oscillator section of your board - they can
occasionally be tricky.

> 6)Last Question:
> this question may sound silly.but can the
> microcontroller really can
> access the program inside the EPROM?i am quite
> confused on the method
> of operation of expanded mode..so,if anyone who have
> use the expanded
> mode,please help me... Certainly. Study the sections in the MCU manual on the
mode control pins MODA and MODB. You don't say which
particular chip you wish to use, but if you go with
the F1, then you don't even need to de-multiplex the
low-order address/data signal on Port C. You can
thereby simplify your external circuitry
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