"to create a general-purpose libre-licensed pinmux
module that can be used with a wide range of interfaces that have
-Open-Drain, Push-Push *and bi-directional* capabilities, as well as
+Open-Drain, Push-Pull *and bi-directional* capabilities, as well as
optional pull-up and pull-down resistors, in an IDENTICAL fashion to
that of ALL major well-known embedded SoCs from ST Micro, Cypress,
Texas Instruments, NXP, Rockchip, Allwinner and many many others".
* The IO pad shall have pull-up enable, pull-down enable, variable
frequency de-bounce (schmidt trigger), tri-state capability,
- variable current drive (on input), Open Drain and CMOS Push-Push.
+ variable current drive (on input), Open Drain and CMOS Push-Pull.
* Certain functions shall have the ability to control whether
IO pads will be input or output (not the GPIO registers).
* Number of wires shall be minimised especially in cases where
the entire SoC's GPIO domain, is simply not a good idea: all sensors
and peripherals which do not have a variable (VREF) capability for the
logic side, or coincidentally are not at the exact same fixed voltage,
-will simply not be compatible if they are high-speed CMOS-level push-push
+will simply not be compatible if they are high-speed CMOS-level push-pull
driven. Open-Drain on the other hand can be handled with a MOSFET for
two-way or even a diode for one-way depending on the levels, but this means
significant numbers of external components if the number of lines is large.
So, selecting a fixed voltage (such as 1.8v or 3.3v) results in a bit of a
problem: external level-shifting is required on pretty much absolutely every
-single pin, particularly the high-speed (CMOS) push-push I/O. An example: the
+single pin, particularly the high-speed (CMOS) push-pull I/O. An example: the
DM9000 is best run at 3.3v. A fixed 1.8v FlexBus would
require a whopping 18 pins (possibly even 24 for a 16-bit-wide bus)
worth of level-shifting, which is not just costly
projects / libreriscv.git / blobdiff