2 Replies Latest reply on Aug 16, 2019 6:27 AM by user_4409276

    对于hyper ram的上初始化有疑问,我一直没有驱动起来hyper ram,我怀疑是上电初始化的问题,因为从hyper ram发出的rwds信号一直是高电平

    user_4409276

      对于hyper ram的上电初始化有疑问,我怀疑我一直没有驱动起来这个memory,因为从hyper  ram 发出的rwds 一直为高电平吧,并且DQ一直是8’h01,希望尽快得到您的帮助

        • 1. Re: 对于hyper ram的上初始化有疑问,我一直没有驱动起来hyper ram,我怀疑是上电初始化的问题,因为从hyper ram发出的rwds信号一直是高电平
          RoyL_01

          你是按照datasheet里7.5节上电要求上电的?完了后怎么操作hyper ram的?

          https://www.cypress.com/file/183506/download

          7.5 Power-Up

          Initialization HyperRAM products include an on-chip voltage sensor used to launch the power-up initialization process. VCC and VCCQ must be applied simultaneously. When the power supply reaches a stable level at or above VCC(min), the device will require tVCS time to complete its self-initialization process. The device must not be selected during power-up. CS# must follow the voltage applied on VCCQ until VCC (min) is reached during power-up, and then CS# must remain HIGH for a further delay of tVCS. A simple pull-up resistor from VCCQ to Chip Select (CS#) can be used to insure safe and proper power-up. If RESET# is LOW during power up, the device delays start of the tVCS period until RESET# is HIGH. The tVCS period is used primarily to perform refresh operations on the DRAM array to initialize it. When initialization is complete, the device is ready for normal operation.

          另,hyper bus 协议参考一下 https://www.cypress.com/file/213356/download

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          • 2. Re: 对于hyper ram的上初始化有疑问,我一直没有驱动起来hyper ram,我怀疑是上电初始化的问题,因为从hyper ram发出的rwds信号一直是高电平
            user_4409276

            您好,我确定我的上电初始化是按照数据手册给的时序,我的cs#reset#都有上拉电阻,具体上电流程是这样的,

            上电时序启动拉低reset#超过200ns ,并且cs#一直保持高电平,经过小于150us的时间再拉低cs#并且执行第一次写操作,您感觉我的上电初始化对吗?

            另一个问题想请教一下,关于自刷新我一直是忽略的,没有任何操作,没次进行读写操作的时候都是拉高cs#400ns左右然后开始进入传输C/A的状态,我现在读写数据只进行6个字节的传输,是不是我的cs#拉高的时间过过长呢。        

            最后一个问题,关于RWDS我这边现在的状态是上电就一直给的是高阻态,但是被从机那边拉高了所以只要是我给高阻态状态RWDS一直就是拉高的状态,这也是我怀疑上电初始化有问题的原因,但是现在我更感觉自刷新操作有很大的问题,希望您给一些关于自刷新延迟建议。主要没驱动起来的现象就是RWDS一直高电平状态,DQ一直是8h01,希望尽快的得道您的回复,谢谢