Hello. My name is Ume Onigiri, and I am gradually getting used to my new department now that my training is over. One day, I received this question from a customer:
"Does Cyclone® V have Power up sequence?"
Ume Onigiri knew. He knew that when he used Cyclone IV in the production training, there was no power up sequence. So he thought that Cyclone V would not have a power up sequence either. But when I checked the Handbook to be sure, I found that Cyclone V did have a power up sequence. I almost gave the wrong answer to the customer.
V series FPGAs have a power up sequence clearly stated in the Handbook. In this article, we will study the power up sequence of Cyclone V.
The power up sequence of Cyclone V is shown in the figure below.
Please refer to this page for more information about each type of power supply.
VCC, VCCE_GXB, and VCCL_GXB must be turned on simultaneously. VCCE_GXB and VCCL_GXB must be turned on at the same time, and VCC_BAT can be turned on at any time.
I also found the following description.
VCCIO and VCCPD must be activated at the same time. This must also be observed.
While these are the restrictions on the power up sequence, there are other points to be noted regarding the power up sequence.
First of all, power must be turned on in a monotonically increasing sequence. If the power supply drops in the middle of startup, it may cause problems such as not being configured.
Furthermore, there is a restriction on the time until the power supply rises. The tRAMP is described in the Datasheet. If the power supply does not start up within this specified time, the configuration will not work properly.
The maximum value of tRAMP differs between Standard POR and Fast POR. tRAMP can be selected between Standard and Fast by the MSEL pin process that selects the configuration mode. See here for more information on this process.
What we learned this time
The power supply is an important part of a device that determines whether or not it will work properly. That's why it's important to follow all of these power startup requirements to the letter.
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