From 24e621a8d8424721ed21ce329d2a28dbf8c35343 Mon Sep 17 00:00:00 2001 From: Dean Camera Date: Fri, 30 Jul 2010 03:52:11 +0000 Subject: Altered the CDC Deivice and Host Class drivers' receive byte routines, so that no data is indicated by a negative return value. Added auto flushing of OUT data to the CDC Host Class driver's USBTask function to automatically flush the send pipe buffer. --- LUFA/Drivers/USB/Class/Host/CDC.h | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) (limited to 'LUFA/Drivers/USB/Class/Host/CDC.h') diff --git a/LUFA/Drivers/USB/Class/Host/CDC.h b/LUFA/Drivers/USB/Class/Host/CDC.h index 640242819..56bcf3147 100644 --- a/LUFA/Drivers/USB/Class/Host/CDC.h +++ b/LUFA/Drivers/USB/Class/Host/CDC.h @@ -236,7 +236,10 @@ uint8_t CDC_Host_SendByte(USB_ClassInfo_CDC_Host_t* const CDCInterfaceInfo, const uint8_t Data) ATTR_NON_NULL_PTR_ARG(1); - /** Determines the number of bytes received by the CDC interface from the device, waiting to be read. + /** Determines the number of bytes received by the CDC interface from the device, waiting to be read. This indicates the number + * of bytes in the IN pipe bank only, and thus the number of calls to \ref CDC_Host_ReceiveByte() which are guaranteed to succeed + * immediately. If multiple bytes are to be received, they should be buffered by the user application, as the pipe bank will not be + * released back to the USB controller until all bytes are read. * * \pre This function must only be called when the Host state machine is in the HOST_STATE_Configured state or the * call will fail. @@ -248,17 +251,17 @@ uint16_t CDC_Host_BytesReceived(USB_ClassInfo_CDC_Host_t* const CDCInterfaceInfo) ATTR_NON_NULL_PTR_ARG(1); /** Reads a byte of data from the device. If no data is waiting to be read of if a USB device is not connected, the function - * returns 0. The \ref CDC_Host_BytesReceived() function should be queried before data is received to ensure that no data - * underflow occurs. + * returns a negative value. The \ref CDC_Host_BytesReceived() function may be queried in advance to determine how many bytes + * are currently buffered in the CDC interface's data receive pipe. * * \pre This function must only be called when the Host state machine is in the HOST_STATE_Configured state or the * call will fail. * * \param[in,out] CDCInterfaceInfo Pointer to a structure containing a CDC Class host configuration and state. * - * \return Next received byte from the device, or 0 if no data received. + * \return Next received byte from the device, or a negative value if no data received. */ - uint8_t CDC_Host_ReceiveByte(USB_ClassInfo_CDC_Host_t* const CDCInterfaceInfo) ATTR_NON_NULL_PTR_ARG(1); + int16_t CDC_Host_ReceiveByte(USB_ClassInfo_CDC_Host_t* const CDCInterfaceInfo) ATTR_NON_NULL_PTR_ARG(1); /** Flushes any data waiting to be sent, ensuring that the send buffer is cleared. * -- cgit v1.2.3