If the first sending was not successful it is better to abort. Then we get a return value of -1 (instead of -2 if the 2nd call will also fail) and we do not need to block even longer, with another timeout.
Since the HID library adds some general HID definitions and structs, it is very useful to also include this in a custom library.
If you dupe the information you have problems of redeclaration.
Having those defintions inside the official HID library is essential for a good working additional HID API.
This commit just shows other that this option is available and not implemented.
You may use this to determine the Led Lights state of a keyboard or transmit data via RAWHID from the PC.
Quick usage guide:
int length = ((setup.wValueH << 8) | setup.wLength);
USB_RecvControl((uint8_t* data, USB_EP_SIZE); // Needs to be splitted into USB_EP_SIZE packets, not shown here. See HID Project.
Alternatively we can only pass the wIndex to getDescriptor but I suggest to just pass the pointer aka reference of the whole setup.
In guess (havent tested this) that this results in more or less the code size but its a) idential with the other functions and b) we late have more flexibility here.
The Code got a quick SerialKeyboard.ino test
The field is now built on-the-fly on the stack and sent over USB.
This change increase Flash usage and decrease SRAM usage:
before: 6114 / 241
after: 6152 / 216 (removed HIDDescriptor field)
delta: +38 / -25
SRAM is a much more scarse resource and this change free up to
about 10% of the "base" usage.
This change allows the compiler to handle callbacks resolution.
Callbacks now must be implemented on the class that extends
PUSBListNode and this is forced by compiler by means of pure
virtual methods.
Also the calls to HID.interface() and HID.endpoint() can now
be simplified to interface() and endpoint() respectively since
the methods are no more static.
The method
int8_t PluggableUSB::addFunction(PUSBListNode *, uint8_t *)
has been changed to
bool PluggableUSB::plug(PUSBListNode *node)
since both EP and Interfaces are now saved directly into node
In particular HIDDescriptorListNode.cb has been renamed to
HIDDescriptorListNode.descriptor because it contains decriptor data
and not callbacks.
Moreover the HID_Descriptor.descriptor field has been renamed
to HID_Descriptor.data so the structure has now two fields length
and data.
typedef struct __attribute__((packed)) {
uint16_t length;
const void* data;
} HID_Descriptor;
class HIDDescriptorListNode {
public:
HIDDescriptorListNode *next = NULL;
const HID_Descriptor *descriptor;
HIDDescriptorListNode(const HID_Descriptor *d) : descriptor(d) { }
};
This imply a change in the use of the node from:
node->cb->lenght
node->cd->descriptor
to
node->descriptor->length
node->descriptor->data
with this PR you can add
\#include Keyboard.h
\#include Mouse.h
\#include HID.h
in the top of the sketch and you will expose a Mouse+Keyboard
From the library pow, simply add
static HID_Descriptor cb = {
.length = sizeof(_hidReportDescriptor),
.descriptor = _hidReportDescriptor,
};
static HIDDescriptorListNode node(&cb);
HID.AppendDescriptor(&node);
in the class' constructor and you are done!
