Messages in this thread | | | From | Linus Walleij <> | Date | Tue, 26 Jul 2022 09:23:08 +0200 | Subject | Re: [PATCH 1/2] gpio: gpio-74x164: add support for CDx4HC4094 |
| |
On Tue, Jul 26, 2022 at 8:55 AM Andy Shevchenko <andy.shevchenko@gmail.com> wrote: > On Tue, Jul 26, 2022 at 12:22 AM Linus Walleij <linus.walleij@linaro.org> wrote:
> > Well it will work, because all values come out, however *during* > > the transfer, not *after* the transfer as intended with the > > STR signal. > > No. I think you missed one little but crucial detail. The strobe is > edge, not level, while you consider CS as a level signal (only).
Aha! Then it works :)
> See Figure 7 and Table 9 in the datasheet you linked to. When STR is > low, the data is not changed. Maybe it's not clear in this datasheet, > I found somewhere > in a more clear table. > > > At least how I see it ...? > > If what you are saying is true, the hardware is totally broken and I > wouldn't use it. I.o.w. if the strobe passes all data when it's at low > level and latches at low-to-high, it's broken by definition in my > point of view.
I have seen strobes that are level-active in my life, but if you say this one isn't then all is fine!
Yours, Linus Walleij
| |