Revision 0.03 was performed on the controller board and the 4x4 board. These boards were revised first since they weren't clustered with many offshoots and any mistakes don't ripple through numerous boards. It was a way to iron out the kinks before turning to the cookie-cutter boards.
The big revisions to the controller board were adding Revision numbers to each board to keep them organized online and in a parts bin. Pull-up resistors were added to the data lines as well.
On the 4x4 board, the most complex of the key-holder boards, more changes were necessary, and space started to become critical. Pull-up resistors were added to each key or terminal so the boards wouldn't have to rely on the weak programmable pull-up resistors in the IO expander chips. Revision numbers were added to the board. Another note was added which advised that key switches should be soldered last. The name was changed, so it was easier to identify than before. The reset pin was tied to a pull-up resistor, and the pin was broken out so the IO expander could be reset by jumpering it to ground.
The rest of the posts for this project have been arranged by date.
First time here?
Completed projects from year 1
Completed projects from year 2
Completed projects from year 3
Completed projects from year 4
Completed projects from year 5
Disclaimer for http://24hourengineer.blogspot.com/
This disclaimer must be intact and whole. This disclaimer must be included if a project is distributed.
All information in this blog, or linked by this blog, is not to be taken as advice or solicitation. Anyone attempting to replicate, in whole or in part, is responsible for the outcome and procedure. Any loss of functionality, money, property or similar, is the responsibility of those involved in the replication.
All digital communication regarding the email address 24hourengineer@gmail.com becomes the intellectual property of Brian McEvoy. Any information contained within these messages may be distributed or retained at the discretion of Brian McEvoy. Any email sent to this address, or any email account owned by Brian McEvoy, cannot be used to claim property or assets.
Comments to the blog may be utilized or erased at the discretion of the owner. No one posting may claim property or assets based on their post.
This blog, including pictures and text, is copyright to Brian McEvoy.
2018-03-18
The big revisions to the controller board were adding Revision numbers to each board to keep them organized online and in a parts bin. Pull-up resistors were added to the data lines as well.
On the 4x4 board, the most complex of the key-holder boards, more changes were necessary, and space started to become critical. Pull-up resistors were added to each key or terminal so the boards wouldn't have to rely on the weak programmable pull-up resistors in the IO expander chips. Revision numbers were added to the board. Another note was added which advised that key switches should be soldered last. The name was changed, so it was easier to identify than before. The reset pin was tied to a pull-up resistor, and the pin was broken out so the IO expander could be reset by jumpering it to ground.
First updated boards
The rest of the posts for this project have been arranged by date.
First time here?
Completed projects from year 1
Completed projects from year 2
Completed projects from year 3
Completed projects from year 4
Completed projects from year 5
Disclaimer for http://24hourengineer.blogspot.com/
This disclaimer must be intact and whole. This disclaimer must be included if a project is distributed.
All information in this blog, or linked by this blog, is not to be taken as advice or solicitation. Anyone attempting to replicate, in whole or in part, is responsible for the outcome and procedure. Any loss of functionality, money, property or similar, is the responsibility of those involved in the replication.
All digital communication regarding the email address 24hourengineer@gmail.com becomes the intellectual property of Brian McEvoy. Any information contained within these messages may be distributed or retained at the discretion of Brian McEvoy. Any email sent to this address, or any email account owned by Brian McEvoy, cannot be used to claim property or assets.
Comments to the blog may be utilized or erased at the discretion of the owner. No one posting may claim property or assets based on their post.
This blog, including pictures and text, is copyright to Brian McEvoy.
2018-03-18
Comments
Post a Comment