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stm32f1: ubshid: add re-enumeration forcing.

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This makes the demo reliably work on "generic" "other" style f1 boards
out of the box.
This commit is contained in:
Karl Palsson
2016-10-04 20:50:17 +00:00
parent 23001dfbcb
commit 8fae7811a8
1 changed files with 15 additions and 0 deletions
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15
examples/stm32/f1/other/usb_hid/usbhid.c
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@@ -279,6 +279,21 @@ int main(void)
rcc_clock_setup_in_hsi_out_48mhz(); rcc_clock_setup_in_hsi_out_48mhz();
rcc_periph_clock_enable(RCC_GPIOA); rcc_periph_clock_enable(RCC_GPIOA);
/*
* This is a somewhat common cheap hack to trigger device re-enumeration
* on startup. Assuming a fixed external pullup on D+, (For USB-FS)
* setting the pin to output, and driving it explicitly low effectively
* "removes" the pullup. The subsequent USB init will "take over" the
* pin, and it will appear as a proper pullup to the host.
* The magic delay is somewhat arbitrary, no guarantees on USBIF
* compliance here, but "it works" in most places.
*/
gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_2_MHZ,
GPIO_CNF_OUTPUT_PUSHPULL, GPIO12);
gpio_clear(GPIOA, GPIO12);
for (unsigned i = 0; i < 800000; i++) {
__asm__("nop");
}
usbd_dev = usbd_init(&st_usbfs_v1_usb_driver, &dev_descr, &config, usb_strings, 3, usbd_control_buffer, sizeof(usbd_control_buffer)); usbd_dev = usbd_init(&st_usbfs_v1_usb_driver, &dev_descr, &config, usb_strings, 3, usbd_control_buffer, sizeof(usbd_control_buffer));
usbd_register_set_config_callback(usbd_dev, hid_set_config); usbd_register_set_config_callback(usbd_dev, hid_set_config);