Re: MSP430F449 LCD lines as digital O ports

Started by September 29, 2003
Hi Kobus, you wrote on 29/09/2003 16:27:24:

The "static" on a LCD driver means that it is not multiplexed, but LCD
is allways drived with AC voltage. The outputs will be a sqare wave and you will
need a "back plane" AC output (generated by LCD controller also,
COM0).
The datasheet of MSP430F449 says that S2..S33 outputs is for the LCD driver only
and they aren't accessed by no other way.

Regards,

Nelson M. Sicuro (Brazil)

>I am also struggeling with the lcd lines of the
F449. I dont know how to
>access the lines. What register do you use to output a steady 3.0V on
>s0, s1, s2 etc.? 
>
>Does static mean you can use them as steady outputs (I'm totally new to
>the lcd scene and dont know the terms)? 
>
>What want to read flash (4 meg parralel flash chip) with my msp. Which
>means I nead 22 address lines and 8 data lines. Unfortunately I already
>use 26 lines to control other stuf. The 32 lcd outputs is just sitting
>there.
>
>Thanks
>Kobus
>
>P.S. A code snippet would help a lot since this is a first for me (the
>msp that is)
>
>
>
>.
>
> 
>
>">http://docs.yahoo.com/info/terms/ 
>
>



Beginning Microcontrollers with the MSP430

The data sheet for the F449 DOES NOT SAY THIS. SLAS344C clearly 
indicates that, like every other MSP430 micro, the Sxx pins are also 
available as general purpose I/O. read the table on page 6.

Further reading in SLAU056C chapter 8, page 7 shows that Ports 3-6 are 
available as general purpose I/O simply by correctly connfiguring PnSEL 
as 0x00H to select I/O fu7nction then setting PnDIR to determine correct 
port pin direction.

Once you configure the pins for LCD operation you cannot easily use them 
for normal I/O operations as they are mostly multiplexed signals. 
However the default setting for all pins is general purpose I/O.

Al

sicnemelpor@sicn... wrote:

> Hi Kobus, you wrote on 29/09/2003 16:27:24:
> 
> The "static" on a LCD driver means that it is not multiplexed,
but
> LCD is allways drived with AC voltage. The outputs will be a sqare
> wave and you will need a "back plane" AC output (generated by LCD
> controller also, COM0). The datasheet of MSP430F449 says that S2..S33
> outputs is for the LCD driver only and they aren't accessed by no
> other way.
> 
> Regards,
> 
> Nelson M. Sicuro (Brazil)
> 
> 
>> I am also struggeling with the lcd lines of the F449. I dont know
>> how to access the lines. What register do you use to output a
>> steady 3.0V on s0, s1, s2 etc.?
>> 
>> Does static mean you can use them as steady outputs (I'm totally
>> new to the lcd scene and dont know the terms)?
>> 
>> What want to read flash (4 meg parralel flash chip) with my msp.
>> Which means I nead 22 address lines and 8 data lines. Unfortunately
>> I already use 26 lines to control other stuf. The 32 lcd outputs is
>> just sitting there.
>> 
>> Thanks Kobus
>> 
>> P.S. A code snippet would help a lot since this is a first for me
>> (the msp that is)
>> 
>> 
>> 
>> .
>> 
>> 
>> 
>> ">http://docs.yahoo.com/info/terms/
>> 
>> 
> 
> 
> 
> 
> ------------------------ Yahoo! Groups Sponsor
> ---------------------~--> Upgrade to 128-Bit SSL Security! 
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> ">http://docs.yahoo.com/info/terms/
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Uh?
What I understand from the table at page 6 of SLAS344C is that some pins 
are devoted to LCD function, S10 to S17, S20 to S23 are LCD drive only both 
on the 80 pin and the 100 pin count part.
"Kobus" is looking for 56 i/o pins while ports P1 to P6 provide for
48.
I think this is the matter of the discussion.
It is not completely untrue that the LCD-only outputs cannot be used as 
output pins, as they do are output pins. But it may be tricky, indeed.
I cannot say that I have done this, but, in principle, one can hold the 
Basic Timer, so that the LCD pins will not change in time,

at this point the output at the corresponding COM will be reflected at the 
LCD pins that are "0" in the LCDM registers,

  while the LCD pins that are set as "1" in the LCDM register will be
at 
the opposite logic level, i.e. if COM is 1 they will be 0 and vice-versa.

The state of the COM pin, however, I do not know how you can control it, 
unless you go monitor it with a regular I/O pin (or an analog input or the 
comparator input .. or ...)

Hope this will help

Antonio Morra



"ONESTONE" wrote :
>The data sheet for the F449 DOES NOT SAY THIS.
SLAS344C clearly
>indicates that, like every other MSP430 micro, the Sxx pins are also
>available as general purpose I/O. read the table on page 6.
>
>Further reading in SLAU056C chapter 8, page 7 shows that Ports 3-6 are
>available as general purpose I/O simply by correctly connfiguring PnSEL
>as 0x00H to select I/O fu7nction then setting PnDIR to determine correct
>port pin direction.
>
>Once you configure the pins for LCD operation you cannot easily use them
>for normal I/O operations as they are mostly multiplexed signals.
>However the default setting for all pins is general purpose I/O.
>
>Al
>
>sicnemelpor@sicn... wrote:
>
> > Hi Kobus, you wrote on 29/09/2003 16:27:24:
> >
> > The "static" on a LCD driver means that it is not
multiplexed, but
> > LCD is allways drived with AC voltage. The outputs will be a sqare
> > wave and you will need a "back plane" AC output (generated
by LCD
> > controller also, COM0). The datasheet of MSP430F449 says that S2..S33
> > outputs is for the LCD driver only and they aren't accessed by no
> > other way.
> >
> > Regards,
> >
> > Nelson M. Sicuro (Brazil)
> >
> >
> >> I am also struggeling with the lcd lines of the F449. I dont know
> >> how to access the lines. What register do you use to output a
> >> steady 3.0V on s0, s1, s2 etc.?
> >>
> >> Does static mean you can use them as steady outputs (I'm totally
> >> new to the lcd scene and dont know the terms)?
> >>
> >> What want to read flash (4 meg parralel flash chip) with my msp.
> >> Which means I nead 22 address lines and 8 data lines.
Unfortunately
> >> I already use 26 lines to control other stuf. The 32 lcd outputs
is
> >> just sitting there.
> >>
> >> Thanks Kobus
> >>
> >> P.S. A code snippet would help a lot since this is a first for me
> >> (the msp that is)
> >>
> >>




Ing. Morra Antonio wrote:

> Uh?
> What I understand from the table at page 6 of SLAS344C is that some pins 
> are devoted to LCD function, S10 to S17, S20 to S23 are LCD drive only both

> on the 80 pin and the 100 pin count part.
> "Kobus" is looking for 56 i/o pins while ports P1 to P6 provide
for 48.
> I think this is the matter of the discussion.

You're  right, I read it that he was looking to use the port based LCD 
pins as I/O and couldn't figure out how.

> It is not completely untrue that the LCD-only
outputs cannot be used as 
> output pins, as they do are output pins. But it may be tricky, indeed.
> I cannot say that I have done this, but, in principle, one can hold the 
> Basic Timer, so that the LCD pins will not change in time,

It would be easier I think to add bus latches to his existing design. He 
only needs to find 8 more signals. He has 22 left, without touching his 
existing I/O he can use 8 for the data bus, 8 for address output, 3 to 
select one of 3 8 bit '573 latches to hold the address 1 to select 
address output enable/chip select, and that leaves two for flash 
read/write control. A bit slow. The alternative would be to set the 
segment voltage to close to three volts, then use one I/O pin as a 
gating signal for the COM signal, to 3 octal buffers so that address can 
be done in a single hit. The buffers give you a decent logic level 
output, but could be done away with using an S/R type latch, assuming 
that the FLASH timing is compatible with the period of each segment. It 
would be more complex than the simple scheme above, for very little 
gain. This isn't going to work at typical memory bus speeds anyway.

Al

> 
> at this point the output at the corresponding COM will be reflected at the 
> LCD pins that are "0" in the LCDM registers,
> 
>   while the LCD pins that are set as "1" in the LCDM register
will be at 
> the opposite logic level, i.e. if COM is 1 they will be 0 and vice-versa.
> 
> The state of the COM pin, however, I do not know how you can control it, 
> unless you go monitor it with a regular I/O pin (or an analog input or the 
> comparator input .. or ...)
> 
> Hope this will help
> 
> Antonio Morra
> 
> 
> 
> "ONESTONE" wrote :
> 
>>The data sheet for the F449 DOES NOT SAY THIS. SLAS344C clearly
>>indicates that, like every other MSP430 micro, the Sxx pins are also
>>available as general purpose I/O. read the table on page 6.

Whoops, I should have read ALL of the table, not just the port pins. I 
guess I should lay off the morphine next time I answer a question on a 
chip I don't use!! Mea Culpa!

>>
>>Further reading in SLAU056C chapter 8, page 7 shows that Ports 3-6 are
>>available as general purpose I/O simply by correctly connfiguring PnSEL
>>as 0x00H to select I/O fu7nction then setting PnDIR to determine correct
>>port pin direction.
>>
>>Once you configure the pins for LCD operation you cannot easily use them
>>for normal I/O operations as they are mostly multiplexed signals.
>>However the default setting for all pins is general purpose I/O.
>>
>>Al
>>
>>sicnemelpor@sicn... wrote:
>>
>>
>>>Hi Kobus, you wrote on 29/09/2003 16:27:24:
>>>
>>>The "static" on a LCD driver means that it is not
multiplexed, but
>>>LCD is allways drived with AC voltage. The outputs will be a sqare
>>>wave and you will need a "back plane" AC output (generated
by LCD
>>>controller also, COM0). The datasheet of MSP430F449 says that
S2..S33
>>>outputs is for the LCD driver only and they aren't accessed by no
>>>other way.
>>>
>>>Regards,
>>>
>>>Nelson M. Sicuro (Brazil)
>>>
>>>
>>>
>>>>I am also struggeling with the lcd lines of the F449. I dont
know
>>>>how to access the lines. What register do you use to output a
>>>>steady 3.0V on s0, s1, s2 etc.?
>>>>
>>>>Does static mean you can use them as steady outputs (I'm totally
>>>>new to the lcd scene and dont know the terms)?
>>>>
>>>>What want to read flash (4 meg parralel flash chip) with my msp.
>>>>Which means I nead 22 address lines and 8 data lines.
Unfortunately
>>>>I already use 26 lines to control other stuf. The 32 lcd outputs
is
>>>>just sitting there.
>>>>
>>>>Thanks Kobus
>>>>
>>>>P.S. A code snippet would help a lot since this is a first for
me
>>>>(the msp that is)
>>>>
>>>>
> 
> 
> 
> 
> 
> .
> 
>  
> 
> ">http://docs.yahoo.com/info/terms/ 
> 
> 
> 


Hi Gentlemen

After a phone call with TI they told me that this should be possible 
but better not to do so because TI can't guarantee for this function 
in the future versions of the MSP430F449.

Now I changed my design and use two 8 bit shift register with 
latches (type 4094) as a port extender and this works fine.

Thank you for your help

See you

 --- In msp430@msp4..., onestone <onestone@b...> wrote:
> 
> 
> Ing. Morra Antonio wrote:
> 
> > Uh?
> > What I understand from the table at page 6 of SLAS344C is that 
some pins 
> > are devoted to LCD function, S10 to S17, S20
to S23 are LCD 
drive only both 
> > on the 80 pin and the 100 pin count part.
> > "Kobus" is looking for 56 i/o pins while ports P1 to P6
provide 
for 48.
> > I think this is the matter of the discussion.
> 
> You're  right, I read it that he was looking to use the port based 
LCD 
> pins as I/O and couldn't figure out how.
> 
> > It is not completely untrue that the LCD-only outputs cannot be 
used as 
> > output pins, as they do are output pins. But
it may be tricky, 
indeed.
> > I cannot say that I have done this, but, in
principle, one can 
hold the 
> > Basic Timer, so that the LCD pins will not
change in time,
> 
> It would be easier I think to add bus latches to his existing 
design. He 
> only needs to find 8 more signals. He has 22 left,
without 
touching his 
> existing I/O he can use 8 for the data bus, 8 for
address output, 
3 to 
> select one of 3 8 bit '573 latches to hold the
address 1 to select 
> address output enable/chip select, and that leaves two for flash 
> read/write control. A bit slow. The alternative would be to set 
the 
> segment voltage to close to three volts, then use
one I/O pin as a 
> gating signal for the COM signal, to 3 octal buffers so that 
address can 
> be done in a single hit. The buffers give you a
decent logic level 
> output, but could be done away with using an S/R type latch, 
assuming 
> that the FLASH timing is compatible with the
period of each 
segment. It 
> would be more complex than the simple scheme
above, for very 
little 
> gain. This isn't going to work at typical memory
bus speeds anyway.
> 
> Al
> 
> > 
> > at this point the output at the corresponding COM will be 
reflected at the 
> > LCD pins that are "0" in the LCDM
registers,
> > 
> >   while the LCD pins that are set as "1" in the LCDM
register 
will be at 
> > the opposite logic level, i.e. if COM is 1
they will be 0 and 
vice-versa.
> > 
> > The state of the COM pin, however, I do not know how you can 
control it, 
> > unless you go monitor it with a regular I/O
pin (or an analog 
input or the 
> > comparator input .. or ...)
> > 
> > Hope this will help
> > 
> > Antonio Morra
> > 
> > 
> > 
> > "ONESTONE" wrote :
> > 
> >>The data sheet for the F449 DOES NOT SAY THIS. SLAS344C clearly
> >>indicates that, like every other MSP430 micro, the Sxx pins are 
also
> >>available as general purpose I/O. read the
table on page 6.
> 
> Whoops, I should have read ALL of the table, not just the port 
pins. I 
> guess I should lay off the morphine next time I
answer a question 
on a 
> chip I don't use!! Mea Culpa!
> 
> >>
> >>Further reading in SLAU056C chapter 8, page 7 shows that Ports 3-
6 are
> >>available as general purpose I/O simply by
correctly 
connfiguring PnSEL
> >>as 0x00H to select I/O fu7nction then
setting PnDIR to determine 
correct
> >>port pin direction.
> >>
> >>Once you configure the pins for LCD operation you cannot easily 
use them
> >>for normal I/O operations as they are
mostly multiplexed signals.
> >>However the default setting for all pins is general purpose I/O.
> >>
> >>Al
> >>
> >>sicnemelpor@m... wrote:
> >>
> >>
> >>>Hi Kobus, you wrote on 29/09/2003 16:27:24:
> >>>
> >>>The "static" on a LCD driver means that it is not
multiplexed, 
but
> >>>LCD is allways drived with AC voltage.
The outputs will be a 
sqare
> >>>wave and you will need a "back
plane" AC output (generated by 
LCD
> >>>controller also, COM0). The datasheet
of MSP430F449 says that 
S2..S33
> >>>outputs is for the LCD driver only and
they aren't accessed by 
no
> >>>other way.
> >>>
> >>>Regards,
> >>>
> >>>Nelson M. Sicuro (Brazil)
> >>>
> >>>
> >>>
> >>>>I am also struggeling with the lcd lines of the F449. I
dont 
know
> >>>>how to access the lines. What
register do you use to output a
> >>>>steady 3.0V on s0, s1, s2 etc.?
> >>>>
> >>>>Does static mean you can use them as steady outputs (I'm 
totally
> >>>>new to the lcd scene and dont know
the terms)?
> >>>>
> >>>>What want to read flash (4 meg parralel flash chip) with my

msp.
> >>>>Which means I nead 22 address
lines and 8 data lines. 
Unfortunately
> >>>>I already use 26 lines to control
other stuf. The 32 lcd 
outputs is
> >>>>just sitting there.
> >>>>
> >>>>Thanks Kobus
> >>>>
> >>>>P.S. A code snippet would help a lot since this is a first
for 
me
> >>>>(the msp that is)
> >>>>
> >>>>
> > 
> > 
> > 
> > 
> > 
> > .
> > 
> >  
> > 
> > ">http://docs.yahoo.com/info/terms/ 
> > 
> > 
> >