djsundog/circuitpython
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

stm32/usbd_cdc_interface: Add CTS flow control option for USB VCP.

Browse Source 
Enabled by default, but disabled when REPL is connected to the VCP (this is
the existing behaviour).  Can be configured at run-time with, eg:

    pyb.USB_VCP().init(flow=pyb.USB_VCP.RTS | pyb.USB_VCP.CTS)
This commit is contained in:
Andrew Leech 2019-04-24 10:24:24 +10:00 committed by Damien George
parent 6b4666f8cf
commit 2397b44062
3 changed files with 34 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
ports/stm32/usb.c
View File

@ -634,6 +634,12 @@ STATIC void pyb_usb_vcp_print(const mp_print_t *print, mp_obj_t self_in, mp_prin
void usb_vcp_attach_to_repl(const pyb_usb_vcp_obj_t *self, bool attached) {
self->cdc_itf->attached_to_repl = attached;
if (attached) {
// Default behavior is non-blocking when attached to repl
self->cdc_itf->flow &= ~USBD_CDC_FLOWCONTROL_CTS;
} else {
self->cdc_itf->flow |= USBD_CDC_FLOWCONTROL_CTS;
}
}
/// \classmethod \constructor()
@ -791,6 +797,7 @@ STATIC const mp_rom_map_elem_t pyb_usb_vcp_locals_dict_table[] = {
// class constants
{ MP_ROM_QSTR(MP_QSTR_RTS), MP_ROM_INT(USBD_CDC_FLOWCONTROL_RTS) },
{ MP_ROM_QSTR(MP_QSTR_CTS), MP_ROM_INT(USBD_CDC_FLOWCONTROL_CTS) },
};
STATIC MP_DEFINE_CONST_DICT(pyb_usb_vcp_locals_dict, pyb_usb_vcp_locals_dict_table);
@ -808,18 +815,13 @@ STATIC mp_uint_t pyb_usb_vcp_read(mp_obj_t self_in, void *buf, mp_uint_t size, i
STATIC mp_uint_t pyb_usb_vcp_write(mp_obj_t self_in, const void *buf, mp_uint_t size, int *errcode) {
pyb_usb_vcp_obj_t *self = MP_OBJ_TO_PTR(self_in);
if (self->cdc_itf->attached_to_repl) {
usbd_cdc_tx_always(self->cdc_itf, (const byte*)buf, size);
return size;
} else {
int ret = usbd_cdc_tx(self->cdc_itf, (const byte*)buf, size, 0);
if (ret == 0) {
// return EAGAIN error to indicate non-blocking
*errcode = MP_EAGAIN;
return MP_STREAM_ERROR;
}
return ret;
int ret = usbd_cdc_tx_flow(self->cdc_itf, (const byte*)buf, size);
if (ret == 0) {
// return EAGAIN error to indicate non-blocking
*errcode = MP_EAGAIN;
return MP_STREAM_ERROR;
}
return ret;
}
STATIC mp_uint_t pyb_usb_vcp_ioctl(mp_obj_t self_in, mp_uint_t request, uintptr_t arg, int *errcode) {

19
ports/stm32/usbd_cdc_interface.c
View File

@ -74,6 +74,12 @@ uint8_t *usbd_cdc_init(usbd_cdc_state_t *cdc_in) {
cdc->rx_buf_full = false;
cdc->tx_need_empty_packet = 0;
cdc->connect_state = USBD_CDC_CONNECT_STATE_DISCONNECTED;
if (cdc->attached_to_repl) {
// Default behavior is non-blocking when attached to repl
cdc->flow &= ~USBD_CDC_FLOWCONTROL_CTS;
} else {
cdc->flow |= USBD_CDC_FLOWCONTROL_CTS;
}
// Return the buffer to place the first USB OUT packet
return cdc->rx_packet_buf;
@ -292,6 +298,19 @@ int usbd_cdc_tx_half_empty(usbd_cdc_itf_t *cdc) {
return tx_waiting <= USBD_CDC_TX_DATA_SIZE / 2;
}
// Writes only the data that fits if flow & CTS, else writes all data
// Returns number of bytes actually written to the device
int usbd_cdc_tx_flow(usbd_cdc_itf_t *cdc, const uint8_t *buf, uint32_t len) {
if (cdc->flow & USBD_CDC_FLOWCONTROL_CTS) {
// Only write as much as can fit in tx buffer
return usbd_cdc_tx(cdc, buf, len, 0);
} else {
// Never block, keep most recent data in rolling buffer
usbd_cdc_tx_always(cdc, buf, len);
return len;
}
}
// timout in milliseconds.
// Returns number of bytes written to the device.
int usbd_cdc_tx(usbd_cdc_itf_t *cdc, const uint8_t *buf, uint32_t len, uint32_t timeout) {

2
ports/stm32/usbd_cdc_interface.h
View File

@ -46,6 +46,7 @@
// Flow control settings
#define USBD_CDC_FLOWCONTROL_NONE (0)
#define USBD_CDC_FLOWCONTROL_RTS (1)
#define USBD_CDC_FLOWCONTROL_CTS (2)
typedef struct _usbd_cdc_itf_t {
usbd_cdc_state_t base; // state for the base CDC layer
@ -75,6 +76,7 @@ static inline int usbd_cdc_is_connected(usbd_cdc_itf_t *cdc) {
}
int usbd_cdc_tx_half_empty(usbd_cdc_itf_t *cdc);
int usbd_cdc_tx_flow(usbd_cdc_itf_t *cdc, const uint8_t *buf, uint32_t len);
int usbd_cdc_tx(usbd_cdc_itf_t *cdc, const uint8_t *buf, uint32_t len, uint32_t timeout);
void usbd_cdc_tx_always(usbd_cdc_itf_t *cdc, const uint8_t *buf, uint32_t len);