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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* Taken from ST Cube library and heavily modified. See below for original
* copyright header.
*/
/**
******************************************************************************
* @file USB_Device/CDC_Standalone/Src/usbd_cdc_interface.c
* @author MCD Application Team
* @version V1.0.1
* @date 26-February-2014
* @brief Source file for USBD CDC interface
******************************************************************************
* @attention
*
* <h2><center>© COPYRIGHT(c) 2014 STMicroelectronics</center></h2>
*
* Licensed under MCD-ST Liberty SW License Agreement V2, (the "License");
* You may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.st.com/software_license_agreement_liberty_v2
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
******************************************************************************
*/
/* Includes ------------------------------------------------------------------*/
#include <stdint.h>
#include "usbd_hid_interface.h"
#include "py/obj.h"
#include "irq.h"
#include "usb.h"
uint8_t *usbd_hid_init(usbd_hid_itf_t *hid, USBD_HandleTypeDef *pdev) {
hid->usb = pdev;
hid->current_read_buffer = 0;
hid->last_read_len = 0;
hid->current_write_buffer = 0;
// Return the buffer to place the first USB OUT packet
return hid->buffer[hid->current_write_buffer];
}
// Data received over USB OUT endpoint is processed here.
// len: number of bytes received into the buffer we passed to USBD_HID_ReceivePacket
// Returns USBD_OK if all operations are OK else USBD_FAIL
int8_t usbd_hid_receive(usbd_hid_itf_t *hid, size_t len) {
hid->current_write_buffer = !hid->current_write_buffer;
hid->last_read_len = len;
// initiate next USB packet transfer, to append to existing data in buffer
USBD_HID_ReceivePacket(hid->usb, hid->buffer[hid->current_write_buffer]);
// Set NAK to indicate we need to process read buffer
USBD_HID_SetNAK(hid->usb);
return USBD_OK;
}
// Returns number of ready rx buffers.
int usbd_hid_rx_num(usbd_hid_itf_t *hid) {
return hid->current_read_buffer != hid->current_write_buffer;
}
// timout in milliseconds.
// Returns number of bytes read from the device.
int usbd_hid_rx(usbd_hid_itf_t *hid, size_t len, uint8_t *buf, uint32_t timeout) {
// Wait until we have buffer to read
uint32_t start = HAL_GetTick();
while (hid->current_read_buffer == hid->current_write_buffer) {
// Wraparound of tick is taken care of by 2's complement arithmetic.
if (HAL_GetTick() - start >= timeout) {
// timeout
return 0;
}
if (query_irq() == IRQ_STATE_DISABLED) {
// IRQs disabled so buffer will never be filled; return immediately
return 0;
}
__WFI(); // enter sleep mode, waiting for interrupt
}
// There is not enough space in buffer
if (len < hid->last_read_len) {
return 0;
}
// Copy bytes from device to user buffer
memcpy(buf, hid->buffer[hid->current_read_buffer], hid->last_read_len);
hid->current_read_buffer = !hid->current_read_buffer;
// Clear NAK to indicate we are ready to read more data
USBD_HID_ClearNAK(hid->usb);
// Success, return number of bytes read
return hid->last_read_len;
}
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