Forum Discussion
Occasional ContributorAbout MAX10 IO pin pull-up
- I can confirm that MAX10 pins are high impedance (> 10 Mohm) with 0 V supply.
Occasional ContributorThank you for answering.
Thank you for explaining the details. Is it okay to understand the following?
1) Weak pull-up is disabled by default, but can be enabled through settings from the Quartus Prime software.
2) When weak pull-up is enabled, it prevents I/O pins from floating during power-up and power-down.
3) I/O pins are floating when the power is completely off.
Also, I apologize for the repeated questions, but I would appreciate it if you could explain the following points.
4) If weak pull-up is enabled, are the I/O pins floating from power-on until POR operates? Or will the weak pull-up be enabled from the moment the power is turned on, and the power supply voltage will be visible during power-up?
We apologize for the inconvenience and appreciate your understanding.
Super ContributorHi,
my reading of MAX10 device handbook gives a slightly different picture. There are basically three different states:
1. Supply voltage below POR threshold
According to Fig. 2.7 and related description, weak pull-up is unconditionally enabled, drivers are disabled.
2. Configuration mode
State of weak pull-up is controlled by ICB, default is enabled. See Table 2.5.
3. User mode
Weak pull-up is controlled by general and pin specific configuration.
Regarding state during power down and missing supply. If power down triggers POR comparator, same situation as power up. Zero supply - not specified. Depends on Vgs,th of pull-up transistor, the question sounds somewhat sophistic to me.
- Yamada1
Thank you for your comment.
In the answer from AqidAyman_Intel, it was said that weak pull-up is disabled by default.
Since it was a machine translation, there was a possibility of a mistranslation, so I checked to see if it was recognized.
Also, I'm sorry for the lack of words.
What I wanted to check in question 4) was whether the I/O pins are floating when the power is off, or whether they are connected to weak pull-ups.
This is because the device connected to the I/O of the circuit under investigation starts up first, and I wanted to know the state of the MAX10's I/O pins when the power is turned off.
We apologize for the inconvenience, but it would be helpful if you could teach us.
- FvMI can confirm that MAX10 pins are high impedance (> 10 Mohm) with 0 V supply.
