Is it a bad idea to replace pull-up resistors with hard pull-ups?
How could we transfer large amounts of energy sourced in space to Earth?
Why can't RGB or bicolour LEDs produce a decent yellow?
Why was the Ancient One so hesitant to teach Dr. Strange the art of sorcery?
How are one-time password generators like Google Authenticator different from having two passwords?
Is there a faster way to calculate Abs[z]^2 numerically?
Increase height of laser cut design file for enclosure
Can I use my laptop, which says 240V, in the USA?
How old is Captain America at the end of "Avengers: Endgame"?
How to slow yourself down (for playing nice with others)
Why does "decimal.TryParse()" always return 0 for the input string "-1" in the below code?
Washer drain pipe overflow
Can you book a one-way ticket to the UK on a visa?
We are two immediate neighbors who forged our own powers to form concatenated relationship. Who are we?
Control variables and other independent variables
Is there a need for better software for writers?
How do I compare the result of "1d20+x, with advantage" to "1d20+y, without advantage", assuming x < y?
How do I get past a 3-year ban from overstay with VWP?
Ubuntu won't let me edit or delete .vimrc file
Is the homebrew weapon attack cantrip 'Arcane Strike' balanced?
Early arrival in Australia, early hotel check in not available
stdout and stderr redirection to different files
The lexical root of the past tense forms differs from the lexical root of the infinitive form
What are some possible reasons that a father's name is missing from a birth certificate - England?
What food production methods would allow a metropolis like New York to become self sufficient
Is it a bad idea to replace pull-up resistors with hard pull-ups?
.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty margin-bottom:0;
$begingroup$
On many of my designs, there are ICs which have mode selection or similar inputs that are permanently pulled up or down using resistors.
If I replaced all these with simple hard pullups or pulldowns I would probably save 10 placements per board on average, which is not nothing. Is this a bad idea? And if so why?
pcd-design
asked 1 hour ago
DrewDrew
2,0631515
$endgroup$
add a comment |
$begingroup$
On many of my designs, there are ICs which have mode selection or similar inputs that are permanently pulled up or down using resistors.
If I replaced all these with simple hard pullups or pulldowns I would probably save 10 placements per board on average, which is not nothing. Is this a bad idea? And if so why?
pcd-design
asked 1 hour ago
DrewDrew
2,0631515
$endgroup$
2
$begingroup$
Include a schematic of what you mean, what's a "hard pullup" do you mean a direct connection (no series resistor) to the supply? Include a link to an example of an IC for which you want to do this. Someone put the resistors in the schematic, ask that person why they did that.
$endgroup$
– Bimpelrekkie
1 hour ago
1
$begingroup$
On rev 0 of any board I tend to strap any configuration or spare input pins high or low using resistors (sometimes zero-ohm), because it may provide a quick fix in an "oh @#$%" moment. With zero-ohms you can remove the resistor, or remove the resistor and use the pad for a wire, etc. Once I'm sure of the design, if production volumes are high enough that it matters I'll make a pass through and just strap things high or low with copper.
$endgroup$
– TimWescott
49 mins ago
add a comment |
$begingroup$
On many of my designs, there are ICs which have mode selection or similar inputs that are permanently pulled up or down using resistors.
If I replaced all these with simple hard pullups or pulldowns I would probably save 10 placements per board on average, which is not nothing. Is this a bad idea? And if so why?
pcd-design
asked 1 hour ago
DrewDrew
2,0631515
$endgroup$
On many of my designs, there are ICs which have mode selection or similar inputs that are permanently pulled up or down using resistors.
If I replaced all these with simple hard pullups or pulldowns I would probably save 10 placements per board on average, which is not nothing. Is this a bad idea? And if so why?
pcd-design
pcd-design
asked 1 hour ago
DrewDrew
2,0631515
asked 1 hour ago
DrewDrew
2,0631515
asked 1 hour ago
DrewDrew
2,0631515
asked 1 hour ago
DrewDrew
2,0631515
asked 1 hour ago
DrewDrew
2,0631515
2,0631515
2
$begingroup$
Include a schematic of what you mean, what's a "hard pullup" do you mean a direct connection (no series resistor) to the supply? Include a link to an example of an IC for which you want to do this. Someone put the resistors in the schematic, ask that person why they did that.
$endgroup$
– Bimpelrekkie
1 hour ago
1
$begingroup$
On rev 0 of any board I tend to strap any configuration or spare input pins high or low using resistors (sometimes zero-ohm), because it may provide a quick fix in an "oh @#$%" moment. With zero-ohms you can remove the resistor, or remove the resistor and use the pad for a wire, etc. Once I'm sure of the design, if production volumes are high enough that it matters I'll make a pass through and just strap things high or low with copper.
$endgroup$
– TimWescott
49 mins ago
add a comment |
2
$begingroup$
Include a schematic of what you mean, what's a "hard pullup" do you mean a direct connection (no series resistor) to the supply? Include a link to an example of an IC for which you want to do this. Someone put the resistors in the schematic, ask that person why they did that.
$endgroup$
– Bimpelrekkie
1 hour ago
1
$begingroup$
On rev 0 of any board I tend to strap any configuration or spare input pins high or low using resistors (sometimes zero-ohm), because it may provide a quick fix in an "oh @#$%" moment. With zero-ohms you can remove the resistor, or remove the resistor and use the pad for a wire, etc. Once I'm sure of the design, if production volumes are high enough that it matters I'll make a pass through and just strap things high or low with copper.
$endgroup$
– TimWescott
49 mins ago
2
2
$begingroup$
Include a schematic of what you mean, what's a "hard pullup" do you mean a direct connection (no series resistor) to the supply? Include a link to an example of an IC for which you want to do this. Someone put the resistors in the schematic, ask that person why they did that.
$endgroup$
– Bimpelrekkie
1 hour ago
$begingroup$
Include a schematic of what you mean, what's a "hard pullup" do you mean a direct connection (no series resistor) to the supply? Include a link to an example of an IC for which you want to do this. Someone put the resistors in the schematic, ask that person why they did that.
$endgroup$
– Bimpelrekkie
1 hour ago
1
1
$begingroup$
On rev 0 of any board I tend to strap any configuration or spare input pins high or low using resistors (sometimes zero-ohm), because it may provide a quick fix in an "oh @#$%" moment. With zero-ohms you can remove the resistor, or remove the resistor and use the pad for a wire, etc. Once I'm sure of the design, if production volumes are high enough that it matters I'll make a pass through and just strap things high or low with copper.
$endgroup$
– TimWescott
49 mins ago
$begingroup$
On rev 0 of any board I tend to strap any configuration or spare input pins high or low using resistors (sometimes zero-ohm), because it may provide a quick fix in an "oh @#$%" moment. With zero-ohms you can remove the resistor, or remove the resistor and use the pad for a wire, etc. Once I'm sure of the design, if production volumes are high enough that it matters I'll make a pass through and just strap things high or low with copper.
$endgroup$
– TimWescott
49 mins ago
add a comment |
3 Answers
3
active
oldest
votes
$begingroup$
I asked a similar question on the eevblog forum some time ago. I had this idea in my head that any signal I needed permanently low I would tie hard to ground, and any signal that I needed permanently high I would tie up via a resistor.
I didnt really know from where or why I used this scheme, so I asked about it. I think it may have been something that I picked up somewhere that was more applicable in the TTL days.
EEVBlog - Pull-up resistors - technically necessary vs preference?
The general consensus seemed to be, and as Huisman suggests, unless you need to be able to pull the signal in the opposite direction, you can simply pull it hard up/down.
edit: worth noting that my question was in relation to CMOS based devices - it may still be applicable/necessary if you are playing with TTL families.
More technical reasons revolved around noise immunity, especially if your pull up resistor values were of a high value.
As I am writing this, other reasons I can think of for wanting to use pull ups/downs might include troubleshooting abilities, "hidden features", or debug/service mode selection for example.
Since that thread I am no longer using pull ups unless I need them functionally.
edited 53 mins ago
Greenonline
1,07521024
answered 1 hour ago
Tom STom S
512
New contributor
Tom S is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
1
$begingroup$
Yes, it was a requirement for TTL Hi to prevent secondary breakdown current on overvoltage transients to supply. But not for CMOS. Although my TE's would add them for testability since it serves no function, I said fault detect is adequate with inputs used.
$endgroup$
– Sunnyskyguy EE75
1 hour ago
add a comment |
$begingroup$
The idea of pull-up / pull-down a signal is that the signal is being pulled high or pulled down low most of the time, but can sometimes be pulled down or pulled high respectively.
In the case you want to pull down a signal incidentally that is pulled up most of the time, you want to use a pull-up resistor to prevent huge current drawn from the supply.
So, if your circuit really uses pull-up or pull-down resistors as described above, don't remove them. (For example, when a pin is open collector.)
If in your circuit a signal needs to high or low forever (when the supply is present) and no other component can change the state of this signal, then you can hard-wire it. Those signal are not called pulled-up, but high, and, respectively not called pulled-down, but low.
answered 1 hour ago
HuismanHuisman
2,063315
$endgroup$
add a comment |
$begingroup$
The answer will be in the datasheet. If the logic input operating voltage specification includes VCC or V+ then connecting directly to positive supply is OK.
answered 1 hour ago
TransistorTransistor
91.1k788195
$endgroup$
add a comment |
Your Answer
StackExchange.ifUsing("editor", function ()
return StackExchange.using("schematics", function ()
StackExchange.schematics.init();
);
, "cicuitlab");
StackExchange.ready(function()
var channelOptions =
tags: "".split(" "),
id: "135"
;
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function()
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled)
StackExchange.using("snippets", function()
createEditor();
);
else
createEditor();
);
function createEditor()
StackExchange.prepareEditor(
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader:
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
,
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
);
);
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2felectronics.stackexchange.com%2fquestions%2f437946%2fis-it-a-bad-idea-to-replace-pull-up-resistors-with-hard-pull-ups%23new-answer', 'question_page');
);
Post as a guest
Required, but never shown
3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
I asked a similar question on the eevblog forum some time ago. I had this idea in my head that any signal I needed permanently low I would tie hard to ground, and any signal that I needed permanently high I would tie up via a resistor.
I didnt really know from where or why I used this scheme, so I asked about it. I think it may have been something that I picked up somewhere that was more applicable in the TTL days.
EEVBlog - Pull-up resistors - technically necessary vs preference?
The general consensus seemed to be, and as Huisman suggests, unless you need to be able to pull the signal in the opposite direction, you can simply pull it hard up/down.
edit: worth noting that my question was in relation to CMOS based devices - it may still be applicable/necessary if you are playing with TTL families.
More technical reasons revolved around noise immunity, especially if your pull up resistor values were of a high value.
As I am writing this, other reasons I can think of for wanting to use pull ups/downs might include troubleshooting abilities, "hidden features", or debug/service mode selection for example.
Since that thread I am no longer using pull ups unless I need them functionally.
edited 53 mins ago
Greenonline
1,07521024
answered 1 hour ago
Tom STom S
512
New contributor
Tom S is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
1
$begingroup$
Yes, it was a requirement for TTL Hi to prevent secondary breakdown current on overvoltage transients to supply. But not for CMOS. Although my TE's would add them for testability since it serves no function, I said fault detect is adequate with inputs used.
$endgroup$
– Sunnyskyguy EE75
1 hour ago
add a comment |
$begingroup$
I asked a similar question on the eevblog forum some time ago. I had this idea in my head that any signal I needed permanently low I would tie hard to ground, and any signal that I needed permanently high I would tie up via a resistor.
I didnt really know from where or why I used this scheme, so I asked about it. I think it may have been something that I picked up somewhere that was more applicable in the TTL days.
EEVBlog - Pull-up resistors - technically necessary vs preference?
The general consensus seemed to be, and as Huisman suggests, unless you need to be able to pull the signal in the opposite direction, you can simply pull it hard up/down.
edit: worth noting that my question was in relation to CMOS based devices - it may still be applicable/necessary if you are playing with TTL families.
More technical reasons revolved around noise immunity, especially if your pull up resistor values were of a high value.
As I am writing this, other reasons I can think of for wanting to use pull ups/downs might include troubleshooting abilities, "hidden features", or debug/service mode selection for example.
Since that thread I am no longer using pull ups unless I need them functionally.
edited 53 mins ago
Greenonline
1,07521024
answered 1 hour ago
Tom STom S
512
New contributor
Tom S is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
1
$begingroup$
Yes, it was a requirement for TTL Hi to prevent secondary breakdown current on overvoltage transients to supply. But not for CMOS. Although my TE's would add them for testability since it serves no function, I said fault detect is adequate with inputs used.
$endgroup$
– Sunnyskyguy EE75
1 hour ago
add a comment |
$begingroup$
I asked a similar question on the eevblog forum some time ago. I had this idea in my head that any signal I needed permanently low I would tie hard to ground, and any signal that I needed permanently high I would tie up via a resistor.
I didnt really know from where or why I used this scheme, so I asked about it. I think it may have been something that I picked up somewhere that was more applicable in the TTL days.
EEVBlog - Pull-up resistors - technically necessary vs preference?
The general consensus seemed to be, and as Huisman suggests, unless you need to be able to pull the signal in the opposite direction, you can simply pull it hard up/down.
edit: worth noting that my question was in relation to CMOS based devices - it may still be applicable/necessary if you are playing with TTL families.
More technical reasons revolved around noise immunity, especially if your pull up resistor values were of a high value.
As I am writing this, other reasons I can think of for wanting to use pull ups/downs might include troubleshooting abilities, "hidden features", or debug/service mode selection for example.
Since that thread I am no longer using pull ups unless I need them functionally.
edited 53 mins ago
Greenonline
1,07521024
answered 1 hour ago
Tom STom S
512
New contributor
Tom S is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
I asked a similar question on the eevblog forum some time ago. I had this idea in my head that any signal I needed permanently low I would tie hard to ground, and any signal that I needed permanently high I would tie up via a resistor.
I didnt really know from where or why I used this scheme, so I asked about it. I think it may have been something that I picked up somewhere that was more applicable in the TTL days.
EEVBlog - Pull-up resistors - technically necessary vs preference?
The general consensus seemed to be, and as Huisman suggests, unless you need to be able to pull the signal in the opposite direction, you can simply pull it hard up/down.
edit: worth noting that my question was in relation to CMOS based devices - it may still be applicable/necessary if you are playing with TTL families.
More technical reasons revolved around noise immunity, especially if your pull up resistor values were of a high value.
As I am writing this, other reasons I can think of for wanting to use pull ups/downs might include troubleshooting abilities, "hidden features", or debug/service mode selection for example.
Since that thread I am no longer using pull ups unless I need them functionally.
edited 53 mins ago
Greenonline
1,07521024
answered 1 hour ago
Tom STom S
512
New contributor
Tom S is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 53 mins ago
Greenonline
1,07521024
edited 53 mins ago
Greenonline
1,07521024
edited 53 mins ago
Greenonline
1,07521024
1,07521024
answered 1 hour ago
Tom STom S
512
New contributor
Tom S is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered 1 hour ago
Tom STom S
512
answered 1 hour ago
Tom STom S
512
512
New contributor
Tom S is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Tom S is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
1
$begingroup$
Yes, it was a requirement for TTL Hi to prevent secondary breakdown current on overvoltage transients to supply. But not for CMOS. Although my TE's would add them for testability since it serves no function, I said fault detect is adequate with inputs used.
$endgroup$
– Sunnyskyguy EE75
1 hour ago
add a comment |
1
$begingroup$
Yes, it was a requirement for TTL Hi to prevent secondary breakdown current on overvoltage transients to supply. But not for CMOS. Although my TE's would add them for testability since it serves no function, I said fault detect is adequate with inputs used.
$endgroup$
– Sunnyskyguy EE75
1 hour ago
1
1
$begingroup$
Yes, it was a requirement for TTL Hi to prevent secondary breakdown current on overvoltage transients to supply. But not for CMOS. Although my TE's would add them for testability since it serves no function, I said fault detect is adequate with inputs used.
$endgroup$
– Sunnyskyguy EE75
1 hour ago
$begingroup$
Yes, it was a requirement for TTL Hi to prevent secondary breakdown current on overvoltage transients to supply. But not for CMOS. Although my TE's would add them for testability since it serves no function, I said fault detect is adequate with inputs used.
$endgroup$
– Sunnyskyguy EE75
1 hour ago
add a comment |
$begingroup$
The idea of pull-up / pull-down a signal is that the signal is being pulled high or pulled down low most of the time, but can sometimes be pulled down or pulled high respectively.
In the case you want to pull down a signal incidentally that is pulled up most of the time, you want to use a pull-up resistor to prevent huge current drawn from the supply.
So, if your circuit really uses pull-up or pull-down resistors as described above, don't remove them. (For example, when a pin is open collector.)
If in your circuit a signal needs to high or low forever (when the supply is present) and no other component can change the state of this signal, then you can hard-wire it. Those signal are not called pulled-up, but high, and, respectively not called pulled-down, but low.
answered 1 hour ago
HuismanHuisman
2,063315
$endgroup$
add a comment |
$begingroup$
The idea of pull-up / pull-down a signal is that the signal is being pulled high or pulled down low most of the time, but can sometimes be pulled down or pulled high respectively.
In the case you want to pull down a signal incidentally that is pulled up most of the time, you want to use a pull-up resistor to prevent huge current drawn from the supply.
So, if your circuit really uses pull-up or pull-down resistors as described above, don't remove them. (For example, when a pin is open collector.)
If in your circuit a signal needs to high or low forever (when the supply is present) and no other component can change the state of this signal, then you can hard-wire it. Those signal are not called pulled-up, but high, and, respectively not called pulled-down, but low.
answered 1 hour ago
HuismanHuisman
2,063315
$endgroup$
add a comment |
$begingroup$
The idea of pull-up / pull-down a signal is that the signal is being pulled high or pulled down low most of the time, but can sometimes be pulled down or pulled high respectively.
In the case you want to pull down a signal incidentally that is pulled up most of the time, you want to use a pull-up resistor to prevent huge current drawn from the supply.
So, if your circuit really uses pull-up or pull-down resistors as described above, don't remove them. (For example, when a pin is open collector.)
If in your circuit a signal needs to high or low forever (when the supply is present) and no other component can change the state of this signal, then you can hard-wire it. Those signal are not called pulled-up, but high, and, respectively not called pulled-down, but low.
answered 1 hour ago
HuismanHuisman
2,063315
$endgroup$
The idea of pull-up / pull-down a signal is that the signal is being pulled high or pulled down low most of the time, but can sometimes be pulled down or pulled high respectively.
In the case you want to pull down a signal incidentally that is pulled up most of the time, you want to use a pull-up resistor to prevent huge current drawn from the supply.
So, if your circuit really uses pull-up or pull-down resistors as described above, don't remove them. (For example, when a pin is open collector.)
If in your circuit a signal needs to high or low forever (when the supply is present) and no other component can change the state of this signal, then you can hard-wire it. Those signal are not called pulled-up, but high, and, respectively not called pulled-down, but low.
answered 1 hour ago
HuismanHuisman
2,063315
edited 1 hour ago
answered 1 hour ago
HuismanHuisman
2,063315
answered 1 hour ago
HuismanHuisman
2,063315
answered 1 hour ago
HuismanHuisman
2,063315
2,063315
add a comment |
add a comment |
$begingroup$
The answer will be in the datasheet. If the logic input operating voltage specification includes VCC or V+ then connecting directly to positive supply is OK.
answered 1 hour ago
TransistorTransistor
91.1k788195
$endgroup$
add a comment |
$begingroup$
The answer will be in the datasheet. If the logic input operating voltage specification includes VCC or V+ then connecting directly to positive supply is OK.
answered 1 hour ago
TransistorTransistor
91.1k788195
$endgroup$
add a comment |
$begingroup$
The answer will be in the datasheet. If the logic input operating voltage specification includes VCC or V+ then connecting directly to positive supply is OK.
answered 1 hour ago
TransistorTransistor
91.1k788195
$endgroup$
The answer will be in the datasheet. If the logic input operating voltage specification includes VCC or V+ then connecting directly to positive supply is OK.
answered 1 hour ago
TransistorTransistor
91.1k788195
answered 1 hour ago
TransistorTransistor
91.1k788195
answered 1 hour ago
TransistorTransistor
91.1k788195
answered 1 hour ago
TransistorTransistor
91.1k788195
91.1k788195
add a comment |
add a comment |
Thanks for contributing an answer to Electrical Engineering Stack Exchange!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
Use MathJax to format equations. MathJax reference.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2felectronics.stackexchange.com%2fquestions%2f437946%2fis-it-a-bad-idea-to-replace-pull-up-resistors-with-hard-pull-ups%23new-answer', 'question_page');
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
2
$begingroup$
Include a schematic of what you mean, what's a "hard pullup" do you mean a direct connection (no series resistor) to the supply? Include a link to an example of an IC for which you want to do this. Someone put the resistors in the schematic, ask that person why they did that.
$endgroup$
– Bimpelrekkie
1 hour ago
1
$begingroup$
On rev 0 of any board I tend to strap any configuration or spare input pins high or low using resistors (sometimes zero-ohm), because it may provide a quick fix in an "oh @#$%" moment. With zero-ohms you can remove the resistor, or remove the resistor and use the pad for a wire, etc. Once I'm sure of the design, if production volumes are high enough that it matters I'll make a pass through and just strap things high or low with copper.
$endgroup$
– TimWescott
49 mins ago