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Track if a USB ZLP is needed on flush #4138

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Track if a USB ZLP is needed on flush #4138

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aaec9e2
Add USB_ENDPOINTS_MASK
sandeepmistry Nov 11, 2015
f667443
Send ZLP (zero length packet) on flush, if last write filled buffer
sandeepmistry Nov 11, 2015
bc80824
Send ZLP in USB_Send if TRANSFER_RELEASE is set on ep
sandeepmistry Nov 17, 2015
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22 changes: 19 additions & 3 deletions hardware/arduino/avr/cores/arduino/USBCore.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -191,6 +191,8 @@ static inline u8 FrameNumber()
//==================================================================
//==================================================================

bool _sendZlp[USB_ENDPOINTS];

u8 USBGetConfiguration(void)
{
return _usbConfiguration;
Expand All @@ -204,7 +206,7 @@ class LockEP
LockEP(u8 ep) : _sreg(SREG)
{
cli();
SetEP(ep & 7);
SetEP(ep & USB_ENDPOINTS_MASK);
}
~LockEP()
{
Expand Down Expand Up @@ -300,8 +302,15 @@ int USB_Send(u8 ep, const void* d, int len)
while (n--)
Send8(*data++);
}
if (!ReadWriteAllowed() || ((len == 0) && (ep & TRANSFER_RELEASE))) // Release full buffer
_sendZlp[ep & USB_ENDPOINTS_MASK] = !ReadWriteAllowed() && (len == 0) && !(ep & TRANSFER_RELEASE);

if (!ReadWriteAllowed()) // Release full buffer
ReleaseTX();

if ((len == 0) && (ep & TRANSFER_RELEASE)) {
while(!ReadWriteAllowed());
ReleaseTX();
}
}
}
TXLED1; // light the TX LED
Expand Down Expand Up @@ -625,8 +634,15 @@ ISR(USB_COM_vect)
void USB_Flush(u8 ep)
{
SetEP(ep);
if (FifoByteCount())

// wait for write access if a ZLP is needed
if (_sendZlp[ep])
while(!ReadWriteAllowed());

if (FifoByteCount() || _sendZlp[ep])
ReleaseTX();

_sendZlp[ep] = false;
}

static inline void USB_ClockDisable()
Expand Down
1 change: 1 addition & 0 deletions hardware/arduino/avr/cores/arduino/USBDesc.h
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,7 @@
#else
#define USB_ENDPOINTS 5 // AtMegaxxU2
#endif
#define USB_ENDPOINTS_MASK 7

#define ISERIAL_MAX_LEN 20

Expand Down