> I have the CMM11E1 version of the HC11 I have never heard of a "CMM11E1 version of the HC11 device". Please explain. Who makes it? What is it? How does it differ from the MC68HC11E1?? >which only works in expanded mode(no single chip available). I can see no reason that an MC68HC11E1 will not work in single chip mode unless _you_ have to have external memory resources attached to the chip. IIRC, your original application program would fit in EEPROM. Is that no longer true. > What I want is to use Ports B & C for I/O operations. Please explain what what makes you think that the E1 cannot be operated in single chip mode with ports B and C functioning as normal discrete I/O ports which will accomplish your objective. Be specific in your explanation and please cite references that verify your claim. IIRC, this thread was about operating the MC68HC11E1 in expanded mode with external memory resources attached. So do you or do you _NOT_ have external memory attached to the chip?? If you do not have external memory attached, why do you insist on operating in expanded mode? > > Your third solution for using the 74373 latch is what I originally > had in mind, but don't know how to start implementing it for I/O. > There is an example of how to decode the address and data buses of the 'HC11 shown in Figure 2-22, "Basic Expanded Mode Connections" Just think of your 74HC540 input buffer as a one byte EPROM device. (Actually you can make multiple ports if you decode the low order address bits. You CANNOT operate without the gated buffer because of the I/O contention that will result when the bus is in write mode. In a similar manner, just think of 74HC373 (or equivalent) latches as single byte RAM devices. > Whats's confusing me also is that why do I need to use a latch if > I'm going to use Port B only for ouput and Port C only for input? In expanded mode you CANNOT use these ports as simple data ports as in single chip mode. In expanded mode Port C is a multiplexed address and data bus and Port B outputs the high order address bus byte. > When the HC11 sends out a memory address on its Port B, can't I just > use those outputs directly and drive whatever i'm going to drive? > I'm not switching the Port from addressing to data mode, so why need > a latch? PLEASE read Section 7 of the White Book. You will discover that the data on Port B changes almost every CPU clock cycle. Your LEDs will flash on for about one microsecond and then the data pattern will change to whatever the next address that the CPU needs to access. > > I hope I was able to make my problem clear. Thanks for the replys > I'm sorry, you now have me thoroughly confused by your references to a CMM11E1 and the proposition that MC68HC11E1s cannot operate in single chip mode. So what is it that you are really trying to do and what is your proposed system configuration. Here are some more suggestions: 1. If you _require_ external memory resources, then operate in expanded mode (using the examples given in the White Book) and select one of the four solutions I gave you previously. Were it my project I would use the SPI interface to create additional I/O ports. 2. If _don't_ require external memory resources, then just start your E1 in special bootstrap mode (which is a single chip moe) and get on with it. 3. Quit messing around with trying to bend the 'E1 devices to something they were not intended to do. A much better solution would be to install a MC68HC711E9 and simply run it in single chip mode. That is the device that Motorola designed to address your application. So use it as intended and get on with your design. Please, help me help you. Bob Smith > -Arax > --- Avoid computer viruses, Practice safe hex --- -- Specializing in small, cost effective embedded control systems -- http://www.smithmachineworks.com/embedprod.html Robert L. (Bob) Smith Smith Machine Works, Inc. 9900 Lumlay Road Richmond, VA 23236 804/745-2608 ----- Original Message ----- From: "araxtypesh" <> To: <> Sent: Saturday, May 22, 2004 5:04 PM Subject: [m68HC11] Re: Help on input/output on Port C/Port B, respectivley > I have the CMM11E1 version of the HC11 which only works in expanded > mode(no single chip available). What I want is to use Ports B & C > for I/O operations. > > Your third solution for using the 74373 latch is what I originally > had in mind, but don't know how to start implementing it for I/O. > > Whats's confusing me also is that why do I need to use a latch if > I'm going to use Port B only for ouput and Port C only for input? > When the Hc11 sends out a memory address on its Port B, can't I just > use those outputs directly and drive whatever i'm going to drive? > I'm not switching the Port from addressing to data mode, so why need > a latch? > > I hope I was able to make my problem clear. Thanks for the replys > > -Arax > --- In , "Bob Smith" <bobsmith5@v...> wrote: > > > What do I have to do to get this to work? I really need the > input & > > > output ports. Worst case scenario, I could use Port E to detect > my > > > logical inputs. > > > > 1. I suggest that you start with a thorough review of Section > 7, "Parallel > > Input/Output" of the White Book, or If you haven't read it yet, I > suggest > > that that is a good place to start. The White Book provides you > with > > detailed descriptions of operation of Port B and Port C in both > Expanded and > > Single Chip modes. > > > > 2. You seem to have the operation of the HC11 in Singe Chip vs. > Expanded > > modes thoroughly confused. You say that you want to operate in > Expanded > > Mode, yet at the same time you want to use Ports B and C for > Single Chip > > mode type operations???? So which is it?? Do you require > Expanded Mode so > > that you can attach external memory resources?? Or, do you need > Ports B and > > C for discrete I/O operations. Make up your mind cause you ain't > gonna get > > it both ways at the same time. I suggest that you also need a > thorough > > review of Section 3, "Configuration and Modes of Operation" so > that you can > > figure out which mode of operation that you require for your > design. > > > > > Although Ports B&C are used for address/data lines which connect > to > > > IC's like a latch, can't I connect the outputs to something like > > > LED's(for example) instead? What does the Hc11 care whether I'm > > > really using the ports for address or data lines? > > > > I can assure you that the 'HC11 doesn't care a bit about what you > do or > > don't attach to Ports B and C in either mode of operation. > However, I can > > also assure you that _you_ will care because when you start the > HC11 in > > Expanded Mode it will drive Ports B and C as if they are being > used as > > memory data and address buses. Again this is all explained to you > in the > > White Book. > > > > For example, you haven't bothered to tell us which 'HC11 variant > you are > > using. Depending on which family variant you are using, you may > or not have > > internal memory resources available to provide the required RESET > vector to > > start your program when you come out of RESET and, thus, if no > internal > > memory resource is available to provide a RESET vector, you _must_ > attach > > external memory to ports B and C to even get your program > running. Assuming > > that you can get your program to start running, I can also assure > that IT > > will care very much about what you attach to Ports B and C. > > > > As far as the 'HC11 caring, it doesn't! The rule of GIGO applies > here! > > > > I can think of four ways to operate in expanded mode and still have > > additional discrete I/O pins available for Input/Output. > > > > 1. Attach a PRU similar to the now obsolete MC68HC24 (once again > RTFM, see > > Section 2.9.3 of the White Book). IIRC I have seen notes that > indicate that > > someone is making a clone of that part. Perhaps someone can help > identify > > that part and its source. > > > > 2. Attach a System Expansion device such as the old WaferScale > (now STM) > > PSD devices. > > > > http://www.st.com/stonline/products/families/memories/psm/index.htm > > > > These give you system expansion RAM and ROM plus replacement ports > for Port > > B and C and additional programmable logic functions. Really neat > devices. > > > > 3. Install some suitable latch and receiver devices to your > memory bus > > (with suitable decoding and strobe logic) to create additional > input and > > output ports that appear to your program as additional memory > cells. > > A Transparent Octal Latch similar to the 74HC373/573 makes a very > nice 8 bit > > output port. > > Buffers similar to the HC540/541 make good input ports. > > > > 4. Use the SPI interface to drive some shift register based input > and > > output expansion ports. > > See the 74HC165 for input ports and the 74HC794. > > > > So . . ., in summary --- RTFM, make up your mind what you really > want to > > do, apply some design skills and move ahead with your design. > > > > If that doesn't get you there, then tell us more about your > requirements and > > ask specific questions about what you are stuck on. > > > > Best wishes, Bob Smith > > > > --- Avoid computer viruses, Practice safe hex --- > > > > -- Specializing in small, cost effective > > embedded control systems -- > > > > http://www.smithmachineworks.com/embedprod.html > > > > > > Robert L. (Bob) Smith > > Smith Machine Works, Inc. > > 9900 Lumlay Road > > Richmond, VA 23236 804/745-2608 > > > > bobsmith5@v... > > > > ----- Original Message ----- > > From: "araxtypesh" <arax@m...> > > To: <> > > Sent: Friday, May 21, 2004 11:42 PM > > Subject: [m68HC11] Re: Help on input/output on Port C/Port B, > respectivley > > > > > > > Although Ports B&C are used for address/data lines which connect > to > > > IC's like a latch, can't I connect the outputs to something like > > > LED's(for example) instead? What does the Hc11 care whether I'm > > > really using the ports for address or data lines? > > > > > > What do I have to do to get this to work? I really need the > input & > > > output ports. Worst case scenario, I could use Port E to detect > my > > > logical inputs. > > > > > > -Arax > > > > > > > > > > > > --- In , Donald E Haselwood > <dhaselwood@v...> > > > wrote: > > > > Arax, > > > > > > > > If you are in expanded mode, Ports B & C supply address/data > for > > > the > > > > external memory. The code you show would be applicable for > single > > > chip > > > > modes of operation. > > > > > > > > Regards, > > > > > > > > Donald E Haselwood > > > > > > > > > > > > At 09:26 PM 5/21/04, you wrote: > > > > >OK, so i'm working on this project using the HC11 in expanded > > > mode. > > > > >I need to figure out two specific things. I need to use Port > B for > > > > >output, and Port C for inputs. > > > > > > > > > >For Port B, I want to be able to say PORTB=0xA3, and have the > pins > > > > >on PortB be 1010 0011, as checked with a voltmeter. I thought > that > > > > >PortB doesn't require any initialization or setting prior > > > registers. > > > > >What am I doing wrong here? > > > > > > > > > >And the second part is to set Port C as an input. Could I > simply > > > > >write this: > > > > >char x; > > > > >DDRC=0xFF; //set all 8-bits to input > > > > >x=PORTC; > > > > > > > > > >Would this code alone work if I actually connected either a > high > > > or > > > > >low voltage reference to the pins on Port C? > > > > > > > > > >thanks in advance, > > > > >-Arax > > > > > > > > > > > > > > > > > > > > > > > > > > > > > >Yahoo! Groups Links > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > ----------------------------- > --------- > > ------ > > > Yahoo! Groups Links > > > > > > a.. To > > > > > > -- ------ > Yahoo! Groups Links > > a.. To |