Forum Discussion
Occasional ContributorAbout MAX10 IO pin pull-up
- I can confirm that MAX10 pins are high impedance (> 10 Mohm) with 0 V supply.
Regular Contributor- Based on the Max 10 Handbook, the output buffers of the Intel MAX 10 device are turned off during system power-up or power-down. The Intel MAX 10 device family does not drive out until the device is configured and working in the recommended operating conditions. The I/O pins are tri-stated during power up or power down. The internal weak pull-up resistors are disabled by default during power up. You need to enable the internal weak pull-up resistors through the Intel Quartus Prime software.
- The weak pull-up resistor in Intel MAX 10 device I/O elements (IOE) keep the I/O pins from floating. Before or during power down, you can drive signals into I/O pins, dedicated input pins, and dedicated clock pins without damaging the Intel MAX 10 devices.
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.
FvMSuper Contributor
Hi,
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.
