what type of SPI communication do I have to use? Half Duplex or Full Duplex?
I think the half Duplex is better because I don't loose 8 clock cycle with the USB Status Registers.
I don't want any delay between the moment an action occures on my HID and the moment when I receive the data on my computer.
So do I have to use the SS signal and select each slave or do I have to use a Daisy-chain?
where the enumeration occures?
I want to use an Arduino UNO as SPI Master and two Host USB Shield from Circuit@Home as SPI Slaves.
You can't connect two USB Host shields to an Arduino.
The OP told nothing about software support.
You can't connect two USB Host shields to an Arduino. The shield supports USB hub, you can talk to several USB devices simultaneously via a single shield.
This is not possible. There will always be a delay because the information has to arrive on the USB host shield, has to be processed there, must be transmitted to the Arduino, processed there as well and finally transmitted to the PC. Every stage needs some time, so a delay unavoidable.Quotewhere the enumeration occures?Which enumeration?
I designed the shield and wrote the code. The low-level support is static, you can't have more than one copy of it.
Quote from: pylon on Oct 09, 2012, 07:41 pmThe OP told nothing about software support. The OP told about reading USB devices. In this case, software support is implied; you can't use this (or any other) shield without some supporting code. As far as simply stacking shields on top of Arduino board, you can use any number of them, especially if you are not planning on applying any electrical power to this stack (otherwise I suggest not exceeding 50).
I only find all the time a complete fabric USB Hub with 4 ports or more.
can I use 2 Host USB shield using a rewiring of the SS pin to communicate with the Arduino Uno?
QuoteI only find all the time a complete fabric USB Hub with 4 ports or more.What's the problem with them? You can close the case of the two additional ports or fill them with hot glue if you really don't want them to be available.Quotecan I use 2 Host USB shield using a rewiring of the SS pin to communicate with the Arduino Uno?Yes, you can but you have to almost completely rewrite the software for it. Don't think of this to be an easy task, you have to have some in-depth knowledge of the USB bus protocol as well as of the used chip set. Sure you have the library for the one shield version but you may get some serious problems extending that for a second shield (as felis already told you).
I think the OP is trying to overcome a lack of physical security with a form of hardware solution to prevent people from accessing mass storage devices. We use endpoint security software. It lets users plug in anything they like, but if it hasn't been authorised, the OS can't access it.
send to the computer using RS232
They are 2 separated SPI slaves. What is the difference is the library between using one or two Host USB shield? What is the difference between a common multiple slaves SPI usage?
QuoteThey are 2 separated SPI slaves. What is the difference is the library between using one or two Host USB shield? What is the difference between a common multiple slaves SPI usage?The library is designed to handle just one board. If the design is made that way you cannot just connect a second board and expect the library to handle that as well. Because your hardware design is quite exotic (with the two shields) nobody did the work yet to change the software to include this use case. If you wanna use two USB host shields you gonna have to rewrite large parts of the library.
Quotesend to the computer using RS232So are you going to emulate a serial mouse and keyboard?