Hi,
I am designing a piece of audio equipment that involves a uController,
an LCD and an analog level chip. The LCD needs 5V digital signals, the
level chip can only work with 3.3V digital commands. The uC can of
course run on either voltage.
I had this plan: run the uC and LCD from 5V, the level chip from 3.3V.
Then drive the level chip control lines from the 5V uC via a resistor.
The voltage at the level chip would rise above 3.3V, the internal
protection diodes would limit that voltage to 3.3V + 0.5V, and the
series resistor limits the current into the protection diodes to < 1mA.
Would that work? Or do I need to get some level translators?
TIA for your advice,
Jan Didden
Driving 3.3V parts from 5V PIC
Started by ●August 27, 2008
Reply by ●August 28, 20082008-08-28
Jan,
Try using a voltage divider, it's really easy to make, just two
resistors. Just remember not to use too high of a resistance or what
you are trying to drive may not have enough current.
James
--- In p..., "jandidden" wrote:
>
> Hi,
>
> I am designing a piece of audio equipment that involves a uController,
> an LCD and an analog level chip. The LCD needs 5V digital signals, the
> level chip can only work with 3.3V digital commands. The uC can of
> course run on either voltage.
>
> I had this plan: run the uC and LCD from 5V, the level chip from 3.3V.
> Then drive the level chip control lines from the 5V uC via a resistor.
> The voltage at the level chip would rise above 3.3V, the internal
> protection diodes would limit that voltage to 3.3V + 0.5V, and the
> series resistor limits the current into the protection diodes to < 1mA.
>
> Would that work? Or do I need to get some level translators?
>
> TIA for your advice,
>
> Jan Didden
>
Try using a voltage divider, it's really easy to make, just two
resistors. Just remember not to use too high of a resistance or what
you are trying to drive may not have enough current.
James
--- In p..., "jandidden" wrote:
>
> Hi,
>
> I am designing a piece of audio equipment that involves a uController,
> an LCD and an analog level chip. The LCD needs 5V digital signals, the
> level chip can only work with 3.3V digital commands. The uC can of
> course run on either voltage.
>
> I had this plan: run the uC and LCD from 5V, the level chip from 3.3V.
> Then drive the level chip control lines from the 5V uC via a resistor.
> The voltage at the level chip would rise above 3.3V, the internal
> protection diodes would limit that voltage to 3.3V + 0.5V, and the
> series resistor limits the current into the protection diodes to < 1mA.
>
> Would that work? Or do I need to get some level translators?
>
> TIA for your advice,
>
> Jan Didden
>
Reply by ●August 28, 20082008-08-28
For the output from the PIC and the input to the level chip, why not use the
open drain outputs from your PIC? Instead of using the internal pullups,
pull them up to 3.3 volts. Of course, you need to select a PIC with the
right number of the right kind of outputs not encumbered by some other
peripheral that you want to use. That is one of the things that makes the
24F so cool, but then that's a 3.3 volt part. You might need to choose a
PIC with more legs than you really want, but most likely not.
--McD
----- Original Message -----
From: "jandidden"
To:
Sent: Tuesday, August 26, 2008 10:44 AM
Subject: [piclist] Driving 3.3V parts from 5V PIC
> Hi,
>
> I am designing a piece of audio equipment that involves a uController,
> an LCD and an analog level chip. The LCD needs 5V digital signals, the
> level chip can only work with 3.3V digital commands. The uC can of
> course run on either voltage.
>
> I had this plan: run the uC and LCD from 5V, the level chip from 3.3V.
> Then drive the level chip control lines from the 5V uC via a resistor.
> The voltage at the level chip would rise above 3.3V, the internal
> protection diodes would limit that voltage to 3.3V + 0.5V, and the
> series resistor limits the current into the protection diodes to < 1mA.
>
> Would that work? Or do I need to get some level translators?
>
> TIA for your advice,
>
> Jan Didden
>
>
> to unsubscribe, go to http://www.yahoogroups.com and follow the
> instructions
open drain outputs from your PIC? Instead of using the internal pullups,
pull them up to 3.3 volts. Of course, you need to select a PIC with the
right number of the right kind of outputs not encumbered by some other
peripheral that you want to use. That is one of the things that makes the
24F so cool, but then that's a 3.3 volt part. You might need to choose a
PIC with more legs than you really want, but most likely not.
--McD
----- Original Message -----
From: "jandidden"
To:
Sent: Tuesday, August 26, 2008 10:44 AM
Subject: [piclist] Driving 3.3V parts from 5V PIC
> Hi,
>
> I am designing a piece of audio equipment that involves a uController,
> an LCD and an analog level chip. The LCD needs 5V digital signals, the
> level chip can only work with 3.3V digital commands. The uC can of
> course run on either voltage.
>
> I had this plan: run the uC and LCD from 5V, the level chip from 3.3V.
> Then drive the level chip control lines from the 5V uC via a resistor.
> The voltage at the level chip would rise above 3.3V, the internal
> protection diodes would limit that voltage to 3.3V + 0.5V, and the
> series resistor limits the current into the protection diodes to < 1mA.
>
> Would that work? Or do I need to get some level translators?
>
> TIA for your advice,
>
> Jan Didden
>
>
> to unsubscribe, go to http://www.yahoogroups.com and follow the
> instructions
Reply by ●August 29, 20082008-08-29
Hi John,
That's a quite good suggestion! In hindsight, why didn't I think about it
myself ;-) ??
Thanks,
Jan Didden
Linear Audio
_____
From: p... [mailto:p...] On Behalf Of
John J. McDonough, WB8RCR
Sent: Thursday, August 28, 2008 11:27 PM
To: p...
Cc: j...@linearaudio.nl
Subject: Re: [piclist] Driving 3.3V parts from 5V PIC
For the output from the PIC and the input to the level chip, why not use the
open drain outputs from your PIC? Instead of using the internal pullups,
pull them up to 3.3 volts. Of course, you need to select a PIC with the
right number of the right kind of outputs not encumbered by some other
peripheral that you want to use. That is one of the things that makes the
24F so cool, but then that's a 3.3 volt part. You might need to choose a
PIC with more legs than you really want, but most likely not.
--McD
----- Original Message -----
From: "jandidden" nl>
To: .com>
Sent: Tuesday, August 26, 2008 10:44 AM
Subject: [piclist] Driving 3.3V parts from 5V PIC
> Hi,
>
> I am designing a piece of audio equipment that involves a uController,
> an LCD and an analog level chip. The LCD needs 5V digital signals, the
> level chip can only work with 3.3V digital commands. The uC can of
> course run on either voltage.
>
> I had this plan: run the uC and LCD from 5V, the level chip from 3.3V.
> Then drive the level chip control lines from the 5V uC via a resistor.
> The voltage at the level chip would rise above 3.3V, the internal
> protection diodes would limit that voltage to 3.3V + 0.5V, and the
> series resistor limits the current into the protection diodes to < 1mA.
>
> Would that work? Or do I need to get some level translators?
>
> TIA for your advice,
>
> Jan Didden
>
>
> to unsubscribe, go to http://www.yahoogro
ups.com and follow the
> instructionsYahoo! Groups Links
That's a quite good suggestion! In hindsight, why didn't I think about it
myself ;-) ??
Thanks,
Jan Didden
Linear Audio
_____
From: p... [mailto:p...] On Behalf Of
John J. McDonough, WB8RCR
Sent: Thursday, August 28, 2008 11:27 PM
To: p...
Cc: j...@linearaudio.nl
Subject: Re: [piclist] Driving 3.3V parts from 5V PIC
For the output from the PIC and the input to the level chip, why not use the
open drain outputs from your PIC? Instead of using the internal pullups,
pull them up to 3.3 volts. Of course, you need to select a PIC with the
right number of the right kind of outputs not encumbered by some other
peripheral that you want to use. That is one of the things that makes the
24F so cool, but then that's a 3.3 volt part. You might need to choose a
PIC with more legs than you really want, but most likely not.
--McD
----- Original Message -----
From: "jandidden" nl>
To: .com>
Sent: Tuesday, August 26, 2008 10:44 AM
Subject: [piclist] Driving 3.3V parts from 5V PIC
> Hi,
>
> I am designing a piece of audio equipment that involves a uController,
> an LCD and an analog level chip. The LCD needs 5V digital signals, the
> level chip can only work with 3.3V digital commands. The uC can of
> course run on either voltage.
>
> I had this plan: run the uC and LCD from 5V, the level chip from 3.3V.
> Then drive the level chip control lines from the 5V uC via a resistor.
> The voltage at the level chip would rise above 3.3V, the internal
> protection diodes would limit that voltage to 3.3V + 0.5V, and the
> series resistor limits the current into the protection diodes to < 1mA.
>
> Would that work? Or do I need to get some level translators?
>
> TIA for your advice,
>
> Jan Didden
>
>
> to unsubscribe, go to http://www.yahoogro
ups.com and follow the
> instructionsYahoo! Groups Links
Reply by ●September 8, 20082008-09-08
3.3V LCD,s are readily available, so are 5V analog devices whether or
not your 'level; chip is an ADC or a pot. Whoever designed the circuit
should have designed in suitably matched parts. For 3.3V LCD's I use
Winstar for character and graphic monochrome, or large colour, and
Tianma for small colour.
When LCDs were hard to find in 3.3V I used a 3.3V micro, and main
circuitry, used a %V supply for the LCD and then drove the control lines
directly from the micro via a 470R resistor to current limit ad prevent
damage to the micro. This worked perfectly fine as the voltage on the
LCD pins was well above their logic threshold.
Cheers
Al
James wrote:
>Jan,
>
>Try using a voltage divider, it's really easy to make, just two
>resistors. Just remember not to use too high of a resistance or what
>you are trying to drive may not have enough current.
>
>James
>
>--- In p..., "jandidden" wrote:
>
>
>>Hi,
>>
>>I am designing a piece of audio equipment that involves a uController,
>>an LCD and an analog level chip. The LCD needs 5V digital signals, the
>>level chip can only work with 3.3V digital commands. The uC can of
>>course run on either voltage.
>>
>>I had this plan: run the uC and LCD from 5V, the level chip from 3.3V.
>>Then drive the level chip control lines from the 5V uC via a resistor.
>>The voltage at the level chip would rise above 3.3V, the internal
>>protection diodes would limit that voltage to 3.3V + 0.5V, and the
>>series resistor limits the current into the protection diodes to < 1mA.
>>
>>Would that work? Or do I need to get some level translators?
>>
>>TIA for your advice,
>>
>>Jan Didden
>>
>>
>>
>
>Yahoo! Groups Links
>
>
>
not your 'level; chip is an ADC or a pot. Whoever designed the circuit
should have designed in suitably matched parts. For 3.3V LCD's I use
Winstar for character and graphic monochrome, or large colour, and
Tianma for small colour.
When LCDs were hard to find in 3.3V I used a 3.3V micro, and main
circuitry, used a %V supply for the LCD and then drove the control lines
directly from the micro via a 470R resistor to current limit ad prevent
damage to the micro. This worked perfectly fine as the voltage on the
LCD pins was well above their logic threshold.
Cheers
Al
James wrote:
>Jan,
>
>Try using a voltage divider, it's really easy to make, just two
>resistors. Just remember not to use too high of a resistance or what
>you are trying to drive may not have enough current.
>
>James
>
>--- In p..., "jandidden" wrote:
>
>
>>Hi,
>>
>>I am designing a piece of audio equipment that involves a uController,
>>an LCD and an analog level chip. The LCD needs 5V digital signals, the
>>level chip can only work with 3.3V digital commands. The uC can of
>>course run on either voltage.
>>
>>I had this plan: run the uC and LCD from 5V, the level chip from 3.3V.
>>Then drive the level chip control lines from the 5V uC via a resistor.
>>The voltage at the level chip would rise above 3.3V, the internal
>>protection diodes would limit that voltage to 3.3V + 0.5V, and the
>>series resistor limits the current into the protection diodes to < 1mA.
>>
>>Would that work? Or do I need to get some level translators?
>>
>>TIA for your advice,
>>
>>Jan Didden
>>
>>
>>
>
>Yahoo! Groups Links
>
>
>
Reply by ●September 8, 20082008-09-08
Hi
I found that a simple voltage divider consisting of a 1.8K and 3.3K resistor in series to ground from the 5 volt output of the mcu and then tapping at the junction of the two resistors to take the signal to the 3.3 v olt device works fine. Don't know if this works in all application so keep that in mind.
Richard
I found that a simple voltage divider consisting of a 1.8K and 3.3K resistor in series to ground from the 5 volt output of the mcu and then tapping at the junction of the two resistors to take the signal to the 3.3 v olt device works fine. Don't know if this works in all application so keep that in mind.
Richard
Reply by ●September 8, 20082008-09-08
Hi Al and others,
In the mean time I have also found that I can drive my Noritake VFD
displays, running at 5V, from the 3.3V micro (there's no status return from
the display).
I wasn't aware of the Winstar 3.3V displays. Anyway, my level chip (CS3318)
doesn't have a 5V equivalent.
Cheers,
Jan Didden
_____
From: p... [mailto:p...] On Behalf Of
Onestone
Sent: Friday, August 29, 2008 1:12 AM
To: p...
Subject: Re: [piclist] Re: Driving 3.3V parts from 5V PIC
3.3V LCD,s are readily available, so are 5V analog devices whether or not
your 'level; chip is an ADC or a pot. Whoever designed the circuit should
have designed in suitably matched parts. For 3.3V LCD's I use Winstar for
character and graphic monochrome, or large colour, and Tianma for small
colour.
When LCDs were hard to find in 3.3V I used a 3.3V micro, and main circuitry,
used a %V supply for the LCD and then drove the control lines directly from
the micro via a 470R resistor to current limit ad prevent damage to the
micro. This worked perfectly fine as the voltage on the LCD pins was well
above their logic threshold.
Cheers
Al
James wrote:
Jan,
Try using a voltage divider, it's really easy to make, just two
resistors. Just remember not to use too high of a resistance or what
you are trying to drive may not have enough current.
James
--- In piclist@yahoogroups .com,
"jandidden" wrote:
Hi,
I am designing a piece of audio equipment that involves a uController,
an LCD and an analog level chip. The LCD needs 5V digital signals, the
level chip can only work with 3.3V digital commands. The uC can of
course run on either voltage.
I had this plan: run the uC and LCD from 5V, the level chip from 3.3V.
Then drive the level chip control lines from the 5V uC via a resistor.
The voltage at the level chip would rise above 3.3V, the internal
protection diodes would limit that voltage to 3.3V + 0.5V, and the
series resistor limits the current into the protection diodes to < 1mA.
Would that work? Or do I need to get some level translators?
TIA for your advice,
Jan Didden
to unsubscribe, go to http://www.yahoogro
ups.com and follow the instructions> yahoo.com/info/terms/
In the mean time I have also found that I can drive my Noritake VFD
displays, running at 5V, from the 3.3V micro (there's no status return from
the display).
I wasn't aware of the Winstar 3.3V displays. Anyway, my level chip (CS3318)
doesn't have a 5V equivalent.
Cheers,
Jan Didden
_____
From: p... [mailto:p...] On Behalf Of
Onestone
Sent: Friday, August 29, 2008 1:12 AM
To: p...
Subject: Re: [piclist] Re: Driving 3.3V parts from 5V PIC
3.3V LCD,s are readily available, so are 5V analog devices whether or not
your 'level; chip is an ADC or a pot. Whoever designed the circuit should
have designed in suitably matched parts. For 3.3V LCD's I use Winstar for
character and graphic monochrome, or large colour, and Tianma for small
colour.
When LCDs were hard to find in 3.3V I used a 3.3V micro, and main circuitry,
used a %V supply for the LCD and then drove the control lines directly from
the micro via a 470R resistor to current limit ad prevent damage to the
micro. This worked perfectly fine as the voltage on the LCD pins was well
above their logic threshold.
Cheers
Al
James wrote:
Jan,
Try using a voltage divider, it's really easy to make, just two
resistors. Just remember not to use too high of a resistance or what
you are trying to drive may not have enough current.
James
--- In piclist@yahoogroups .com,
"jandidden" wrote:
Hi,
I am designing a piece of audio equipment that involves a uController,
an LCD and an analog level chip. The LCD needs 5V digital signals, the
level chip can only work with 3.3V digital commands. The uC can of
course run on either voltage.
I had this plan: run the uC and LCD from 5V, the level chip from 3.3V.
Then drive the level chip control lines from the 5V uC via a resistor.
The voltage at the level chip would rise above 3.3V, the internal
protection diodes would limit that voltage to 3.3V + 0.5V, and the
series resistor limits the current into the protection diodes to < 1mA.
Would that work? Or do I need to get some level translators?
TIA for your advice,
Jan Didden
to unsubscribe, go to http://www.yahoogro
ups.com and follow the instructions> yahoo.com/info/terms/
Reply by ●September 8, 20082008-09-08
BTW Where do you get Winstar modules? Neither Digikey nor Mouser seem to
carry them.
Jan Didden
_____
From: p... [mailto:p...] On Behalf Of
Jan Didden / Linear Audio
Sent: Monday, September 08, 2008 7:57 PM
To: p...
Subject: RE: [piclist] Re: Driving 3.3V parts from 5V PIC
Hi Al and others,
In the mean time I have also found that I can drive my Noritake VFD
displays, running at 5V, from the 3.3V micro (there's no status return from
the display).
I wasn't aware of the Winstar 3.3V displays. Anyway, my level chip (CS3318)
doesn't have a 5V equivalent.
Cheers,
Jan Didden
_____
From: p... [mailto:p...] On Behalf Of
Onestone
Sent: Friday, August 29, 2008 1:12 AM
To: p...
Subject: Re: [piclist] Re: Driving 3.3V parts from 5V PIC
3.3V LCD,s are readily available, so are 5V analog devices whether or not
your 'level; chip is an ADC or a pot. Whoever designed the circuit should
have designed in suitably matched parts. For 3.3V LCD's I use Winstar for
character and graphic monochrome, or large colour, and Tianma for small
colour.
When LCDs were hard to find in 3.3V I used a 3.3V micro, and main circuitry,
used a %V supply for the LCD and then drove the control lines directly from
the micro via a 470R resistor to current limit ad prevent damage to the
micro. This worked perfectly fine as the voltage on the LCD pins was well
above their logic threshold.
Cheers
Al
James wrote:
Jan,
Try using a voltage divider, it's really easy to make, just two
resistors. Just remember not to use too high of a resistance or what
you are trying to drive may not have enough current.
James
--- In piclist@yahoogroups .com,
"jandidden" wrote:
Hi,
I am designing a piece of audio equipment that involves a uController,
an LCD and an analog level chip. The LCD needs 5V digital signals, the
level chip can only work with 3.3V digital commands. The uC can of
course run on either voltage.
I had this plan: run the uC and LCD from 5V, the level chip from 3.3V.
Then drive the level chip control lines from the 5V uC via a resistor.
The voltage at the level chip would rise above 3.3V, the internal
protection diodes would limit that voltage to 3.3V + 0.5V, and the
series resistor limits the current into the protection diodes to < 1mA.
Would that work? Or do I need to get some level translators?
TIA for your advice,
Jan Didden
to unsubscribe, go to http://www.yahoogro
ups.com and follow the instructions> yahoo.com/info/terms/
carry them.
Jan Didden
_____
From: p... [mailto:p...] On Behalf Of
Jan Didden / Linear Audio
Sent: Monday, September 08, 2008 7:57 PM
To: p...
Subject: RE: [piclist] Re: Driving 3.3V parts from 5V PIC
Hi Al and others,
In the mean time I have also found that I can drive my Noritake VFD
displays, running at 5V, from the 3.3V micro (there's no status return from
the display).
I wasn't aware of the Winstar 3.3V displays. Anyway, my level chip (CS3318)
doesn't have a 5V equivalent.
Cheers,
Jan Didden
_____
From: p... [mailto:p...] On Behalf Of
Onestone
Sent: Friday, August 29, 2008 1:12 AM
To: p...
Subject: Re: [piclist] Re: Driving 3.3V parts from 5V PIC
3.3V LCD,s are readily available, so are 5V analog devices whether or not
your 'level; chip is an ADC or a pot. Whoever designed the circuit should
have designed in suitably matched parts. For 3.3V LCD's I use Winstar for
character and graphic monochrome, or large colour, and Tianma for small
colour.
When LCDs were hard to find in 3.3V I used a 3.3V micro, and main circuitry,
used a %V supply for the LCD and then drove the control lines directly from
the micro via a 470R resistor to current limit ad prevent damage to the
micro. This worked perfectly fine as the voltage on the LCD pins was well
above their logic threshold.
Cheers
Al
James wrote:
Jan,
Try using a voltage divider, it's really easy to make, just two
resistors. Just remember not to use too high of a resistance or what
you are trying to drive may not have enough current.
James
--- In piclist@yahoogroups .com,
"jandidden" wrote:
Hi,
I am designing a piece of audio equipment that involves a uController,
an LCD and an analog level chip. The LCD needs 5V digital signals, the
level chip can only work with 3.3V digital commands. The uC can of
course run on either voltage.
I had this plan: run the uC and LCD from 5V, the level chip from 3.3V.
Then drive the level chip control lines from the 5V uC via a resistor.
The voltage at the level chip would rise above 3.3V, the internal
protection diodes would limit that voltage to 3.3V + 0.5V, and the
series resistor limits the current into the protection diodes to < 1mA.
Would that work? Or do I need to get some level translators?
TIA for your advice,
Jan Didden
to unsubscribe, go to http://www.yahoogro
ups.com and follow the instructions> yahoo.com/info/terms/
Reply by ●September 17, 20082008-09-17
www.winstar.com
They supply direct, and usually will supply small numbers. MUCH better
prices than digikey. I pay around 45 for a 20x4 LED backlit display.
they also have built in LCD drive voltages and bcklight controllers for
EL or CCFL in most cases.
Other great sources for displays areTianma. I especially like their
small colour displays, 262K colours about 1' square and simple IIc
interface. around $5 in low volumes and all 3V3, finally Bolymin have a
great range, nearly all 3v displays, from character through to small and
large format graphics in mono and colour, plus ome nice single voltage
OLED panels. My favouriote is the 128128A OLED. these suck current, but
you can program the controller chip to reduce mean curret to quite low
levels. All of these will normally supply direct. I bought just 5 panels
from Bolymi n to try out, and a pair from Tianma, which has since led to
a larger order for 100.
Al
Jan Didden / Linear Audio wrote:
> BTW Where do you get Winstar modules? Neither Digikey nor Mouser seem
> to carry them.
>
> Jan Didden
>
> From: p... [mailto:p...] On
> Behalf Of Jan Didden / Linear Audio
> Sent: Monday, September 08, 2008 7:57 PM
> To: p...
> Subject: RE: [piclist] Re: Driving 3.3V parts from 5V PIC
>
> Hi Al and others,
>
> In the mean time I have also found that I can drive my Noritake VFD
> displays, running at 5V, from the 3.3V micro (there's no status return
> from the display).
> I wasn't aware of the Winstar 3.3V displays. Anyway, my level chip
> (CS3318) doesn't have a 5V equivalent.
>
> Cheers,
>
> Jan Didden
>
> From: p... [mailto:p...] On
> Behalf Of Onestone
> Sent: Friday, August 29, 2008 1:12 AM
> To: p...
> Subject: Re: [piclist] Re: Driving 3.3V parts from 5V PIC
>
> 3.3V LCD,s are readily available, so are 5V analog devices whether or
> not your 'level; chip is an ADC or a pot. Whoever designed the circuit
> should have designed in suitably matched parts. For 3.3V LCD's I use
> Winstar for character and graphic monochrome, or large colour, and
> Tianma for small colour.
>
> When LCDs were hard to find in 3.3V I used a 3.3V micro, and main
> circuitry, used a %V supply for the LCD and then drove the control
> lines directly from the micro via a 470R resistor to current limit ad
> prevent damage to the micro. This worked perfectly fine as the voltage
> on the LCD pins was well above their logic threshold.
>
> Cheers
>
> Al
>
> James wrote:
>
>>Jan,
>>
>>Try using a voltage divider, it's really easy to make, just two
>>resistors. Just remember not to use too high of a resistance or what
>>you are trying to drive may not have enough current.
>>
>>James
>>
>>--- In p..., "jandidden" wrote:
>>
>>
>>>Hi,
>>>
>>>I am designing a piece of audio equipment that involves a uController,
>>>an LCD and an analog level chip. The LCD needs 5V digital signals, the
>>>level chip can only work with 3.3V digital commands. The uC can of
>>>course run on either voltage.
>>>
>>>I had this plan: run the uC and LCD from 5V, the level chip from 3.3V.
>>>Then drive the level chip control lines from the 5V uC via a resistor.
>>>The voltage at the level chip would rise above 3.3V, the internal
>>>protection diodes would limit that voltage to 3.3V + 0.5V, and the
>>>series resistor limits the current into the protection diodes to < 1mA.
>>>
>>>Would that work? Or do I need to get some level translators?
>>>
>>>TIA for your advice,
>>>
>>>Jan Didden
>>>
>>>
>>>
>>
>>Yahoo! Groups Links
>>
>>
>>
>
>
>Internal Virus Database is out-of-date.
>Checked by AVG.
>Version: 7.5.524 / Virus Database: 270.6.15 - Release Date: 2/09/2008 12:00 AM
>
>
They supply direct, and usually will supply small numbers. MUCH better
prices than digikey. I pay around 45 for a 20x4 LED backlit display.
they also have built in LCD drive voltages and bcklight controllers for
EL or CCFL in most cases.
Other great sources for displays areTianma. I especially like their
small colour displays, 262K colours about 1' square and simple IIc
interface. around $5 in low volumes and all 3V3, finally Bolymin have a
great range, nearly all 3v displays, from character through to small and
large format graphics in mono and colour, plus ome nice single voltage
OLED panels. My favouriote is the 128128A OLED. these suck current, but
you can program the controller chip to reduce mean curret to quite low
levels. All of these will normally supply direct. I bought just 5 panels
from Bolymi n to try out, and a pair from Tianma, which has since led to
a larger order for 100.
Al
Jan Didden / Linear Audio wrote:
> BTW Where do you get Winstar modules? Neither Digikey nor Mouser seem
> to carry them.
>
> Jan Didden
>
> From: p... [mailto:p...] On
> Behalf Of Jan Didden / Linear Audio
> Sent: Monday, September 08, 2008 7:57 PM
> To: p...
> Subject: RE: [piclist] Re: Driving 3.3V parts from 5V PIC
>
> Hi Al and others,
>
> In the mean time I have also found that I can drive my Noritake VFD
> displays, running at 5V, from the 3.3V micro (there's no status return
> from the display).
> I wasn't aware of the Winstar 3.3V displays. Anyway, my level chip
> (CS3318) doesn't have a 5V equivalent.
>
> Cheers,
>
> Jan Didden
>
> From: p... [mailto:p...] On
> Behalf Of Onestone
> Sent: Friday, August 29, 2008 1:12 AM
> To: p...
> Subject: Re: [piclist] Re: Driving 3.3V parts from 5V PIC
>
> 3.3V LCD,s are readily available, so are 5V analog devices whether or
> not your 'level; chip is an ADC or a pot. Whoever designed the circuit
> should have designed in suitably matched parts. For 3.3V LCD's I use
> Winstar for character and graphic monochrome, or large colour, and
> Tianma for small colour.
>
> When LCDs were hard to find in 3.3V I used a 3.3V micro, and main
> circuitry, used a %V supply for the LCD and then drove the control
> lines directly from the micro via a 470R resistor to current limit ad
> prevent damage to the micro. This worked perfectly fine as the voltage
> on the LCD pins was well above their logic threshold.
>
> Cheers
>
> Al
>
> James wrote:
>
>>Jan,
>>
>>Try using a voltage divider, it's really easy to make, just two
>>resistors. Just remember not to use too high of a resistance or what
>>you are trying to drive may not have enough current.
>>
>>James
>>
>>--- In p..., "jandidden" wrote:
>>
>>
>>>Hi,
>>>
>>>I am designing a piece of audio equipment that involves a uController,
>>>an LCD and an analog level chip. The LCD needs 5V digital signals, the
>>>level chip can only work with 3.3V digital commands. The uC can of
>>>course run on either voltage.
>>>
>>>I had this plan: run the uC and LCD from 5V, the level chip from 3.3V.
>>>Then drive the level chip control lines from the 5V uC via a resistor.
>>>The voltage at the level chip would rise above 3.3V, the internal
>>>protection diodes would limit that voltage to 3.3V + 0.5V, and the
>>>series resistor limits the current into the protection diodes to < 1mA.
>>>
>>>Would that work? Or do I need to get some level translators?
>>>
>>>TIA for your advice,
>>>
>>>Jan Didden
>>>
>>>
>>>
>>
>>Yahoo! Groups Links
>>
>>
>>
>
>
>Internal Virus Database is out-of-date.
>Checked by AVG.
>Version: 7.5.524 / Virus Database: 270.6.15 - Release Date: 2/09/2008 12:00 AM
>
>
