Instruction manual

Renesas USB MCU and USB ASSP USB Basic Host and Peripheral firmware
R01AN0512EJ0210 Rev.2.10 Page 109 of 157
Apr 1, 2013
5.4 Host call-back functions
5.4.1 HCD call-backs
Call-backs are used so that the user does not need to poll for events. The user application registers a callback in order to
be alerted when, for example, requests made to HCD are completed, and data is has been transferred over USB to the
peripheral. By using call-backs the application is propelled forward by the USB USB-BASIC-F/W stack.
Each table below is named after the function registering the call-back, and the table content explains the nature of the
“called-back” function.
Table 5.3 R_usb_hstd_TransferStart call-back
Name Data Transfer Request call-back function
Call format (*USB_CB_INFO_t)(USB_UTR_t*);
Arguments USB_UTR_t* USB_UTR_t pointer of argument of R_usb_hstd_TransferStart
Return values － － －
Description
This function is executed at the end of a data transfer. This should occur when the number
of bytes specified by the TransferStart function are transmitted, or when a short packet is
received. Transmit/receive data length and the error count are updated. Check the result of
data communications.
Notes
Table 5.4 R_usb_hstd_ChangeDeviceState(USB_MSG_HCD_USBRESET) call-back
Name USB Bus Reset call-back function
Call format (*USB_CB_INFO_t)(USB_UTR_t*, uint16_t, uint16_t)
USB_UTR_t * Pointer to a USB Transfer Structure
uint16_t
USB_NOCONNECT: Not connected
USB_HSCONNECT: Hi-speed device
USB_FSCONNECT: Full-speed device
USB_LSCONNECT: Low-speed device
Arguments
uint16_t NOARGUMENT: Not used
Return values － － －
Description This function is executed at the end of USB bus reset processing.
The communication speed of the connected device is returned as an argument to the call-
back.
The response is “not connected” if disconnection is detected during USB bus reset
processing or if the speed is undefined.
Notes