About MAX10 IO pin pull-up - About MAX10 IO pin pull-up It would be helpful if you could tell me about the pull-up of the IO pin of MAX10. 1) In the UG-M10PWR, it is stated that the tri-state and weak pull-up resistors are enabled during power-up due to the POR circuit, but is this also the case during the power-down sequence? 2) If the power is completely turned off, will the weak pull-up resistor on the I/O pin not work? (In other words, will the I/O pin be floating?) We apologize for the inconvenience and appreciate your understanding. Replies: Re: About MAX10 IO pin pull-up I hope the previous response was sufficient to help you proceed. As we do not receive any response from you on the previous reply have been provided, please login to ‘ https://supporttickets.intel.com’ , view details of the desire request, and post a feed/response within the next 15 days to allow me to continue to support you by replying to this thread. Replies: Re: About MAX10 IO pin pull-up Hello Yamada, I wish to follow up with you. Is there any more support needed on your question? Regards, Aqid Replies: Re: About MAX10 IO pin pull-up I can confirm that MAX10 pins are high impedance (> 10 Mohm) with 0 V supply. Replies: Re: About MAX10 IO pin pull-up 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. Replies: Re: About MAX10 IO pin pull-up 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. Replies: Re: About MAX10 IO pin pull-up Thank 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. Replies: Re: About MAX10 IO pin pull-up 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.