Driving 7 segment displays ?
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Posts: 46,084
Hi,
I am working on a dark room timer that uses the Stamp1 as a count down clock
for my enlarger. So far I am doing good, everything works as expected, but
now, I want do away with my 1 minute mechanical timer completely.
I am currently using a BCD to 7-segment display driver (7447) to make the
numbers 0-9, this takes 4 pins from the stamp. I would like to add another 7
seg. display, but If I do that, I won't have any pins left for the 'Set' and
the 'Start' buttons or the transistor fired Relay "With Suppression Diodes!
[noparse];)[/noparse] "
"
Does anyone know of a 'Serial to 7 segment display driver chip' or maybe
just a serial to BCD? Or maybe even a better way of doing this with
something better than the 7447.
This project doesn't warrant the use of a Stamp2 or sx, the code is simple
and minimal, and since I have the Parallax PIC programmer, I can fry this
into a 16C58A when it's done, and free up my Stamp1.
Chris
I am working on a dark room timer that uses the Stamp1 as a count down clock
for my enlarger. So far I am doing good, everything works as expected, but
now, I want do away with my 1 minute mechanical timer completely.
I am currently using a BCD to 7-segment display driver (7447) to make the
numbers 0-9, this takes 4 pins from the stamp. I would like to add another 7
seg. display, but If I do that, I won't have any pins left for the 'Set' and
the 'Start' buttons or the transistor fired Relay "With Suppression Diodes!
[noparse];)[/noparse] "
"
Does anyone know of a 'Serial to 7 segment display driver chip' or maybe
just a serial to BCD? Or maybe even a better way of doing this with
something better than the 7447.
This project doesn't warrant the use of a Stamp2 or sx, the code is simple
and minimal, and since I have the Parallax PIC programmer, I can fry this
into a 16C58A when it's done, and free up my Stamp1.
Chris
Comments
>Does anyone know of a 'Serial to 7 segment display driver chip' or maybe
>just a serial to BCD? Or maybe even a better way of doing this with
>something better than the 7447.
A great device for this is the maxim MAX7219. It can handle up to eight
digits and only takes 3 lines on the stamp. You can control the number of
digits (and brightness!) in software. The interface code has already been
done (Scott Edwards). Get the chip at:
http://www.maxim-ic.com
Get the code at:
ftp://ftp.nutsvolts.com/pub/nutsvolts/library/stampaps/st_ap10.pdf
Best, Duncan
>Hi,
>
>I am working on a dark room timer that uses the Stamp1 as a count down clock
>for my enlarger. So far I am doing good, everything works as expected, but
>now, I want do away with my 1 minute mechanical timer completely.
>
>I am currently using a BCD to 7-segment display driver (7447) to make the
>numbers 0-9, this takes 4 pins from the stamp. I would like to add another 7
>seg. display, but If I do that, I won't have any pins left for the 'Set' and
>the 'Start' buttons or the transistor fired Relay "With Suppression Diodes!
>[noparse];)[/noparse] "
>"
>
>Does anyone know of a 'Serial to 7 segment display driver chip' or maybe
>just a serial to BCD? Or maybe even a better way of doing this with
>something better than the 7447.
>
>This project doesn't warrant the use of a Stamp2 or sx, the code is simple
>and minimal, and since I have the Parallax PIC programmer, I can fry this
>into a 16C58A when it's done, and free up my Stamp1.
>
>Chris
>
>
If you use 74164's you can create your own Characters within the 7-Segment
Display (7SD) configuration by connecting the outputs of the 74164 directly
to the 7SD and sending the proper 8-Bit pattern to light the appropriate
segment (The 8th bit could be used to drive the decimal point) ... or you
could combine each 74164 with two 7447's and drive two 7SD's to use the
standard 7SD characters. Either way you will only need two stamp pins
(CLOCK and DATA), three stamp pins if you want to make use of the CLEAR on
the 74164, although if you use the SHIFTOUT function on the stamp you
shouldn't need to use the CLEAR. When the SHIFTOUT does it's thing there
will be a brief flicker in the display during the updates anyway without
needing to CLEAR. To CASCADE more than one 74164, connect all of the
clock's(Pin9) in common with one another, connect Qh(Pin13) of the first
74164 to the Serial Inputs (Pin1 & Pin2 - OK to connect these two pins
together) of the second 74164 and so on..., and if you choose to use the
CLEAR(Pin9), connect all of the CLEAR's together, otherwise connect all of
the CLEAR's to Vcc(+5V). Remember to put a .1uF or .01uF across each
74164 as close as possible to pins 7 and 14 ... a good measure for any IC
especially counters, dividers, shift registers, etc.
because it costs less and I only need 2 digits on this project. I have
another question though; I have a bunch of 4013s (CMOS Shift-Registers?)
and would like to know if there is a law against using TTL and CMOS in the
same circuit? It just doesn't seem right to me. I was thinking that while I
wait for my 74164's, I might experiment with using them and the 7447 to
drive my displays. Any 'Red Flags' or warnings about TTL+CMOS circuits
would be welcome.
Chris
Original Message
From: Beau Schwabe [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=3JjF57wFFCghcF2iZL-NEtmpovVwJrCwDiUJeEgvjowzz3Z_rrCPnRshx1g20KHFvBlmrIaK_l9njo24atpDPw]bschwabe@H...[/url
Sent: Saturday, March 18, 2000 4:39 AM
To: basicstamps@egroups.com
Subject: [noparse][[/noparse]basicstamps] Re: Driving 7 segment displays ?
At 11:16 PM 3/17/00 -0500, you wrote:
>Hi,
>
>I am working on a dark room timer that uses the Stamp1 as a count down
clock
>for my enlarger. So far I am doing good, everything works as expected, but
>now, I want do away with my 1 minute mechanical timer completely.
>
>I am currently using a BCD to 7-segment display driver (7447) to make the
>numbers 0-9, this takes 4 pins from the stamp. I would like to add another
7
>seg. display, but If I do that, I won't have any pins left for the 'Set'
and
>the 'Start' buttons or the transistor fired Relay "With Suppression Diodes!
>[noparse];)[/noparse] "
>"
>
>Does anyone know of a 'Serial to 7 segment display driver chip' or maybe
>just a serial to BCD? Or maybe even a better way of doing this with
>something better than the 7447.
>
>This project doesn't warrant the use of a Stamp2 or sx, the code is simple
>and minimal, and since I have the Parallax PIC programmer, I can fry this
>into a 16C58A when it's done, and free up my Stamp1.
>
>Chris
>
>
If you use 74164's you can create your own Characters within the 7-Segment
Display (7SD) configuration by connecting the outputs of the 74164 directly
to the 7SD and sending the proper 8-Bit pattern to light the appropriate
segment (The 8th bit could be used to drive the decimal point) ... or you
could combine each 74164 with two 7447's and drive two 7SD's to use the
standard 7SD characters. Either way you will only need two stamp pins
(CLOCK and DATA), three stamp pins if you want to make use of the CLEAR on
the 74164, although if you use the SHIFTOUT function on the stamp you
shouldn't need to use the CLEAR. When the SHIFTOUT does it's thing there
will be a brief flicker in the display during the updates anyway without
needing to CLEAR. To CASCADE more than one 74164, connect all of the
clock's(Pin9) in common with one another, connect Qh(Pin13) of the first
74164 to the Serial Inputs (Pin1 & Pin2 - OK to connect these two pins
together) of the second 74164 and so on..., and if you choose to use the
CLEAR(Pin9), connect all of the CLEAR's together, otherwise connect all of
the CLEAR's to Vcc(+5V). Remember to put a .1uF or .01uF across each
74164 as close as possible to pins 7 and 14 ... a good measure for any IC
especially counters, dividers, shift registers, etc.
eGroups.com home: http://www.egroups.com/group/basicstamps
http://www.egroups.com - Simplifying group communications
TTL and CMOS are fine together.. ( I also have a load of 4000 series CMOS ICs ).
The only restriction is that TTL is a 5.0 volt system so don't try any higher
voltages.
in some critical timing logic set ups the timing of CMOS and TTL need to be
checked.
Also the current draw from TTL is high so be careful you don't overload the
STAMP's regulated
5.0 volts, if you are using this.
From: "Chris Parasida" <parasida@r...>
To: <basicstamps@egroups.com>
Date sent: Sun, 19 Mar 2000 22:03:31 -0500
Send reply to: basicstamps@egroups.com
Subject: [noparse][[/noparse]basicstamps] Re: Driving 7 segment displays ?
> Thanks Duncan and Beau for the help, I think I'll try Beaus idea first,
> because it costs less and I only need 2 digits on this project. I have
> another question though; I have a bunch of 4013s (CMOS Shift-Registers?)
> and would like to know if there is a law against using TTL and CMOS in the
> same circuit? It just doesn't seem right to me. I was thinking that while I
> wait for my 74164's, I might experiment with using them and the 7447 to
> drive my displays. Any 'Red Flags' or warnings about TTL+CMOS circuits
> would be welcome.
>
> Chris
>
>
>
Original Message
> From: Beau Schwabe [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=N_NN_habv8EWt7SUHrxC32lzCt_7TYHoCipwM6L1bnjEchatgdV1kmS8LBB0iuhdFgq7J6pb7wPVOPcFHbmHb00]bschwabe@H...[/url
> Sent: Saturday, March 18, 2000 4:39 AM
> To: basicstamps@egroups.com
> Subject: [noparse][[/noparse]basicstamps] Re: Driving 7 segment displays ?
>
>
> At 11:16 PM 3/17/00 -0500, you wrote:
> >Hi,
> >
> >I am working on a dark room timer that uses the Stamp1 as a count down
> clock
> >for my enlarger. So far I am doing good, everything works as expected, but
> >now, I want do away with my 1 minute mechanical timer completely.
> >
> >I am currently using a BCD to 7-segment display driver (7447) to make the
> >numbers 0-9, this takes 4 pins from the stamp. I would like to add another
> 7
> >seg. display, but If I do that, I won't have any pins left for the 'Set'
> and
> >the 'Start' buttons or the transistor fired Relay "With Suppression Diodes!
> >[noparse];)[/noparse] "
> >"
> >
> >Does anyone know of a 'Serial to 7 segment display driver chip' or maybe
> >just a serial to BCD? Or maybe even a better way of doing this with
> >something better than the 7447.
> >
> >This project doesn't warrant the use of a Stamp2 or sx, the code is simple
> >and minimal, and since I have the Parallax PIC programmer, I can fry this
> >into a 16C58A when it's done, and free up my Stamp1.
> >
> >Chris
> >
> >
> If you use 74164's you can create your own Characters within the 7-Segment
> Display (7SD) configuration by connecting the outputs of the 74164 directly
> to the 7SD and sending the proper 8-Bit pattern to light the appropriate
> segment (The 8th bit could be used to drive the decimal point) ... or you
> could combine each 74164 with two 7447's and drive two 7SD's to use the
> standard 7SD characters. Either way you will only need two stamp pins
> (CLOCK and DATA), three stamp pins if you want to make use of the CLEAR on
> the 74164, although if you use the SHIFTOUT function on the stamp you
> shouldn't need to use the CLEAR. When the SHIFTOUT does it's thing there
> will be a brief flicker in the display during the updates anyway without
> needing to CLEAR. To CASCADE more than one 74164, connect all of the
> clock's(Pin9) in common with one another, connect Qh(Pin13) of the first
> 74164 to the Serial Inputs (Pin1 & Pin2 - OK to connect these two pins
> together) of the second 74164 and so on..., and if you choose to use the
> CLEAR(Pin9), connect all of the CLEAR's together, otherwise connect all of
> the CLEAR's to Vcc(+5V). Remember to put a .1uF or .01uF across each
> 74164 as close as possible to pins 7 and 14 ... a good measure for any IC
> especially counters, dividers, shift registers, etc.
>
>
>
>
>
>
>
>
>
> eGroups.com home: http://www.egroups.com/group/basicstamps
> http://www.egroups.com - Simplifying group communications
>
>
>
>
>
>
>
> -- Easily schedule meetings and events using the group calendar!
> -- http://www.egroups.com/cal?listname=basicstamps&m=1
>
>
ron... the motor man...
Ronald Doctors
http://www.members.home.net/rdoctors
CMOS --> TTL (Same Supply Voltage)
CMOS (Any gate) >
o
> TTL (Any gate)
| 1K
o--/\/\--> GND
TTL --> CMOS (Same Supply Voltage)
TTL (Any gate) >
o
> CMOS (Any gate)
| 2.2K
o--/\/\--> +5V
>Thanks Duncan and Beau for the help, I think I'll try Beaus idea first,
>because it costs less and I only need 2 digits on this project. I have
>another question though; I have a bunch of 4013s (CMOS Shift-Registers?)
>and would like to know if there is a law against using TTL and CMOS in the
>same circuit? It just doesn't seem right to me. I was thinking that while I
>wait for my 74164's, I might experiment with using them and the 7447 to
>drive my displays. Any 'Red Flags' or warnings about TTL+CMOS circuits
>would be welcome.
>
>Chris
>
>
>
Original Message
>From: Beau Schwabe [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=NiC-NW-pbUtoy2HoI1PpuXEhxDgpR0WMrFJMTvtVctstEOBRq-9QG5TBAxhe9pvLhmniuhNowUpiccdTgcyP]bschwabe@H...[/url
>Sent: Saturday, March 18, 2000 4:39 AM
>To: basicstamps@egroups.com
>Subject: [noparse][[/noparse]basicstamps] Re: Driving 7 segment displays ?
>
>
>At 11:16 PM 3/17/00 -0500, you wrote:
>>Hi,
>>
>>I am working on a dark room timer that uses the Stamp1 as a count down
>clock
>>for my enlarger. So far I am doing good, everything works as expected, but
>>now, I want do away with my 1 minute mechanical timer completely.
>>
>>I am currently using a BCD to 7-segment display driver (7447) to make the
>>numbers 0-9, this takes 4 pins from the stamp. I would like to add another
>7
>>seg. display, but If I do that, I won't have any pins left for the 'Set'
>and
>>the 'Start' buttons or the transistor fired Relay "With Suppression Diodes!
>>[noparse];)[/noparse] "
>>"
>>
>>Does anyone know of a 'Serial to 7 segment display driver chip' or maybe
>>just a serial to BCD? Or maybe even a better way of doing this with
>>something better than the 7447.
>>
>>This project doesn't warrant the use of a Stamp2 or sx, the code is simple
>>and minimal, and since I have the Parallax PIC programmer, I can fry this
>>into a 16C58A when it's done, and free up my Stamp1.
>>
>>Chris
>>
>>
>If you use 74164's you can create your own Characters within the 7-Segment
>Display (7SD) configuration by connecting the outputs of the 74164 directly
>to the 7SD and sending the proper 8-Bit pattern to light the appropriate
>segment (The 8th bit could be used to drive the decimal point) ... or you
>could combine each 74164 with two 7447's and drive two 7SD's to use the
>standard 7SD characters. Either way you will only need two stamp pins
>(CLOCK and DATA), three stamp pins if you want to make use of the CLEAR on
>the 74164, although if you use the SHIFTOUT function on the stamp you
>shouldn't need to use the CLEAR. When the SHIFTOUT does it's thing there
>will be a brief flicker in the display during the updates anyway without
>needing to CLEAR. To CASCADE more than one 74164, connect all of the
>clock's(Pin9) in common with one another, connect Qh(Pin13) of the first
>74164 to the Serial Inputs (Pin1 & Pin2 - OK to connect these two pins
>together) of the second 74164 and so on..., and if you choose to use the
>CLEAR(Pin9), connect all of the CLEAR's together, otherwise connect all of
>the CLEAR's to Vcc(+5V). Remember to put a .1uF or .01uF across each
>74164 as close as possible to pins 7 and 14 ... a good measure for any IC
>especially counters, dividers, shift registers, etc.
>
>
>
>
>
>
>
>
>
>eGroups.com home: http://www.egroups.com/group/basicstamps
>http://www.egroups.com - Simplifying group communications
>
>
>
>
>
>
>
>-- Easily schedule meetings and events using the group calendar!
>-- http://www.egroups.com/cal?listname=basicstamps&m=1
>
>
>
>
though. The BS1 does'nt have a 'Shiftout' command. The BS2 works fine with
the 4013.
So, maybe I'll do the 'Time-Share' method with the transistors, unless
someone knows how to fake a shift-out in the stamp1.
Chris
Original Message
From: Beau Schwabe [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=nbOlsJjaX9c43WJv4kEbfXm4PLMF9NJ15mKQargI8w4rRNqYQEyWRJWmy1uWty1S02ibPgd24PcuiH6nAyeowDQvIQ]bschwabe@H...[/url
Sent: Sunday, March 19, 2000 10:52 PM
To: basicstamps@egroups.com
Subject: [noparse][[/noparse]basicstamps] Re: Driving 7 segment displays ?
Yes!, you can use the 4013's
CMOS --> TTL (Same Supply Voltage)
CMOS (Any gate) >
o
> TTL (Any gate)
| 1K
o--/\/\--> GND
TTL --> CMOS (Same Supply Voltage)
TTL (Any gate) >
o
> CMOS (Any gate)
| 2.2K
o--/\/\--> +5V
>Thanks Duncan and Beau for the help, I think I'll try Beaus idea first,
>because it costs less and I only need 2 digits on this project. I have
>another question though; I have a bunch of 4013s (CMOS Shift-Registers?)
>and would like to know if there is a law against using TTL and CMOS in the
>same circuit? It just doesn't seem right to me. I was thinking that while I
>wait for my 74164's, I might experiment with using them and the 7447 to
>drive my displays. Any 'Red Flags' or warnings about TTL+CMOS circuits
>would be welcome.
>
>Chris
>
>
>
Original Message
>From: Beau Schwabe [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=nbOlsJjaX9c43WJv4kEbfXm4PLMF9NJ15mKQargI8w4rRNqYQEyWRJWmy1uWty1S02ibPgd24PcuiH6nAyeowDQvIQ]bschwabe@H...[/url
>Sent: Saturday, March 18, 2000 4:39 AM
>To: basicstamps@egroups.com
>Subject: [noparse][[/noparse]basicstamps] Re: Driving 7 segment displays ?
>
>
>At 11:16 PM 3/17/00 -0500, you wrote:
>>Hi,
>>
>>I am working on a dark room timer that uses the Stamp1 as a count down
>clock
>>for my enlarger. So far I am doing good, everything works as expected,
but
>>now, I want do away with my 1 minute mechanical timer completely.
>>
>>I am currently using a BCD to 7-segment display driver (7447) to make the
>>numbers 0-9, this takes 4 pins from the stamp. I would like to add another
>7
>>seg. display, but If I do that, I won't have any pins left for the 'Set'
>and
>>the 'Start' buttons or the transistor fired Relay "With Suppression
Diodes!
>>[noparse];)[/noparse] "
>>"
>>
>>Does anyone know of a 'Serial to 7 segment display driver chip' or maybe
>>just a serial to BCD? Or maybe even a better way of doing this with
>>something better than the 7447.
>>
>>This project doesn't warrant the use of a Stamp2 or sx, the code is simple
>>and minimal, and since I have the Parallax PIC programmer, I can fry this
>>into a 16C58A when it's done, and free up my Stamp1.
>>
>>Chris
>>
>>
>If you use 74164's you can create your own Characters within the 7-Segment
>Display (7SD) configuration by connecting the outputs of the 74164 directly
>to the 7SD and sending the proper 8-Bit pattern to light the appropriate
>segment (The 8th bit could be used to drive the decimal point) ... or you
>could combine each 74164 with two 7447's and drive two 7SD's to use the
>standard 7SD characters. Either way you will only need two stamp pins
>(CLOCK and DATA), three stamp pins if you want to make use of the CLEAR on
>the 74164, although if you use the SHIFTOUT function on the stamp you
>shouldn't need to use the CLEAR. When the SHIFTOUT does it's thing there
>will be a brief flicker in the display during the updates anyway without
>needing to CLEAR. To CASCADE more than one 74164, connect all of the
>clock's(Pin9) in common with one another, connect Qh(Pin13) of the first
>74164 to the Serial Inputs (Pin1 & Pin2 - OK to connect these two pins
>together) of the second 74164 and so on..., and if you choose to use the
>CLEAR(Pin9), connect all of the CLEAR's together, otherwise connect all of
>the CLEAR's to Vcc(+5V). Remember to put a .1uF or .01uF across each
>74164 as close as possible to pins 7 and 14 ... a good measure for any IC
>especially counters, dividers, shift registers, etc.
>
>
>
>
>
>
>
>
>
>eGroups.com home: http://www.egroups.com/group/basicstamps
>http://www.egroups.com - Simplifying group communications
>
>
>
>
>
>
>
>-- Easily schedule meetings and events using the group calendar!
>-- http://www.egroups.com/cal?listname=basicstamps&m=1
>
>
>
>
eGroups.com Home: http://www.egroups.com/group/basicstamps/
http://www.egroups.com - Simplifying group communications