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Send a ZLP if data size is multiple of EPX_SIZE for USB sends #63

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Send a ZLP if data size is multiple of EPX_SIZE for USB sends #63

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8a06388
Use EPX_SIZE constant
sandeepmistry Nov 6, 2015
53ae1b9
Make whitespace consistent
sandeepmistry Nov 6, 2015
48e5dbb
Send empty transfer if send data length is a multiple of EPX_SIZE
sandeepmistry Nov 6, 2015
c0b2c7a
Rename sendEmpty to sendZlp
sandeepmistry Nov 13, 2015
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21 changes: 15 additions & 6 deletions cores/arduino/USB/USBCore.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -581,6 +581,9 @@ uint8_t USBDeviceClass::armRecv(uint32_t ep)
uint32_t USBDeviceClass::send(uint32_t ep, const void *data, uint32_t len)
{
uint32_t length = 0;
// if len is a multiple of EPX_SIZE an ZLP needs to be sent
// to indicate end of transfer
bool sendZlp = (len % EPX_SIZE) == 0;

if (!_usbConfiguration)
return -1;
Expand Down Expand Up @@ -621,10 +624,10 @@ uint32_t USBDeviceClass::send(uint32_t ep, const void *data, uint32_t len)
#endif

// Flash area
while (len != 0)
while (len != 0 || sendZlp)
{
if (len >= 64) {
length = 64;
if (len > EPX_SIZE) {
length = EPX_SIZE;
} else {
length = len;
}
Expand All @@ -645,6 +648,12 @@ uint32_t USBDeviceClass::send(uint32_t ep, const void *data, uint32_t len)
while (!usbd.epBank1IsTransferComplete(ep)) {
; // need fire exit.
}

if (len == 0 && sendZlp) {
// empty transfer sent
sendZlp = false;
}

len -= length;
data += length;
}
Expand Down Expand Up @@ -679,12 +688,12 @@ uint32_t USBDeviceClass::sendControl(const void* _data, uint32_t len)
return length;
}

while (len > 0)
{
while (len > 0)
{
sent = armSend(EP0, data + pos, len);
pos += sent;
len -= sent;
}
}

return length;
}
Expand Down