USB device stack, fixes for USBSerial & KL25Z

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USBHAL_KL25Z.cpp

00001 /* Copyright (c) 2010-2011 mbed.org, MIT License
00002 *
00003 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
00004 * and associated documentation files (the "Software"), to deal in the Software without
00005 * restriction, including without limitation the rights to use, copy, modify, merge, publish,
00006 * distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the
00007 * Software is furnished to do so, subject to the following conditions:
00008 *
00009 * The above copyright notice and this permission notice shall be included in all copies or
00010 * substantial portions of the Software.
00011 *
00012 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
00013 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
00014 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
00015 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00016 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
00017 */
00018 
00019 #if defined(TARGET_KL25Z) | defined(TARGET_KL46Z) | defined(TARGET_K20D5M) | defined(TARGET_K64F)
00020 
00021 #include "USBHAL.h"
00022 
00023 USBHAL * USBHAL::instance;
00024 
00025 static volatile int epComplete = 0;
00026 
00027 // Convert physical endpoint number to register bit
00028 #define EP(endpoint) (1<<(endpoint))
00029 
00030 // Convert physical to logical
00031 #define PHY_TO_LOG(endpoint)    ((endpoint)>>1)
00032 
00033 // Get endpoint direction
00034 #define IN_EP(endpoint)     ((endpoint) & 1U ? true : false)
00035 #define OUT_EP(endpoint)    ((endpoint) & 1U ? false : true)
00036 
00037 #define BD_OWN_MASK        (1<<7)
00038 #define BD_DATA01_MASK     (1<<6)
00039 #define BD_KEEP_MASK       (1<<5)
00040 #define BD_NINC_MASK       (1<<4)
00041 #define BD_DTS_MASK        (1<<3)
00042 #define BD_STALL_MASK      (1<<2)
00043 
00044 #define TX    1
00045 #define RX    0
00046 #define ODD   0
00047 #define EVEN  1
00048 // this macro waits a physical endpoint number
00049 #define EP_BDT_IDX(ep, dir, odd) (((ep * 4) + (2 * dir) + (1 *  odd)))
00050 
00051 #define SETUP_TOKEN    0x0D
00052 #define IN_TOKEN       0x09
00053 #define OUT_TOKEN      0x01
00054 #define TOK_PID(idx)   ((bdt[idx].info >> 2) & 0x0F)
00055 
00056 // for each endpt: 8 bytes
00057 typedef struct BDT {
00058     uint8_t   info;       // BD[0:7]
00059     uint8_t   dummy;      // RSVD: BD[8:15]
00060     uint16_t  byte_count; // BD[16:32]
00061     uint32_t  address;    // Addr
00062 } BDT;
00063 
00064 
00065 // there are:
00066 //    * 16 bidirectionnal endpt -> 32 physical endpt
00067 //    * as there are ODD and EVEN buffer -> 32*2 bdt
00068 __attribute__((__aligned__(512))) BDT bdt[NUMBER_OF_PHYSICAL_ENDPOINTS * 2];
00069 uint8_t * endpoint_buffer[(NUMBER_OF_PHYSICAL_ENDPOINTS - 2) * 2];
00070 uint8_t * endpoint_buffer_iso[2*2];
00071 
00072 static uint8_t set_addr = 0;
00073 static uint8_t addr = 0;
00074 
00075 static uint32_t Data1  = 0x55555555;
00076 
00077 static uint32_t frameNumber() {
00078     return((USB0->FRMNUML | (USB0->FRMNUMH << 8)) & 0x07FF);
00079 }
00080 
00081 uint32_t USBHAL::endpointReadcore(uint8_t endpoint, uint8_t *buffer) {
00082     return 0;
00083 }
00084 
00085 USBHAL::USBHAL(void) {
00086     // Disable IRQ
00087     NVIC_DisableIRQ(USB0_IRQn);
00088 
00089 #if defined(TARGET_K64F)
00090     MPU->CESR=0;
00091 #endif
00092     // fill in callback array
00093     epCallback[0] = &USBHAL::EP1_OUT_callback;
00094     epCallback[1] = &USBHAL::EP1_IN_callback;
00095     epCallback[2] = &USBHAL::EP2_OUT_callback;
00096     epCallback[3] = &USBHAL::EP2_IN_callback;
00097     epCallback[4] = &USBHAL::EP3_OUT_callback;
00098     epCallback[5] = &USBHAL::EP3_IN_callback;
00099     epCallback[6] = &USBHAL::EP4_OUT_callback;
00100     epCallback[7] = &USBHAL::EP4_IN_callback;
00101     epCallback[8] = &USBHAL::EP5_OUT_callback;
00102     epCallback[9] = &USBHAL::EP5_IN_callback;
00103     epCallback[10] = &USBHAL::EP6_OUT_callback;
00104     epCallback[11] = &USBHAL::EP6_IN_callback;
00105     epCallback[12] = &USBHAL::EP7_OUT_callback;
00106     epCallback[13] = &USBHAL::EP7_IN_callback;
00107     epCallback[14] = &USBHAL::EP8_OUT_callback;
00108     epCallback[15] = &USBHAL::EP8_IN_callback;
00109     epCallback[16] = &USBHAL::EP9_OUT_callback;
00110     epCallback[17] = &USBHAL::EP9_IN_callback;
00111     epCallback[18] = &USBHAL::EP10_OUT_callback;
00112     epCallback[19] = &USBHAL::EP10_IN_callback;
00113     epCallback[20] = &USBHAL::EP11_OUT_callback;
00114     epCallback[21] = &USBHAL::EP11_IN_callback;
00115     epCallback[22] = &USBHAL::EP12_OUT_callback;
00116     epCallback[23] = &USBHAL::EP12_IN_callback;
00117     epCallback[24] = &USBHAL::EP13_OUT_callback;
00118     epCallback[25] = &USBHAL::EP13_IN_callback;
00119     epCallback[26] = &USBHAL::EP14_OUT_callback;
00120     epCallback[27] = &USBHAL::EP14_IN_callback;
00121     epCallback[28] = &USBHAL::EP15_OUT_callback;
00122     epCallback[29] = &USBHAL::EP15_IN_callback;
00123 
00124 
00125     // choose usb src as PLL
00126     SIM->SOPT2 |= (SIM_SOPT2_USBSRC_MASK | SIM_SOPT2_PLLFLLSEL_MASK);
00127 
00128     // enable OTG clock
00129     SIM->SCGC4 |= SIM_SCGC4_USBOTG_MASK;
00130 
00131     // Attach IRQ
00132     instance = this;
00133     NVIC_SetVector(USB0_IRQn, (uint32_t)&_usbisr);
00134     NVIC_EnableIRQ(USB0_IRQn);
00135 
00136     // USB Module Configuration
00137     // Reset USB Module
00138     USB0->USBTRC0 |= USB_USBTRC0_USBRESET_MASK;
00139     while(USB0->USBTRC0 & USB_USBTRC0_USBRESET_MASK);
00140 
00141     // Set BDT Base Register
00142     USB0->BDTPAGE1 = (uint8_t)((uint32_t)bdt>>8);
00143     USB0->BDTPAGE2 = (uint8_t)((uint32_t)bdt>>16);
00144     USB0->BDTPAGE3 = (uint8_t)((uint32_t)bdt>>24);
00145 
00146     // Clear interrupt flag
00147     USB0->ISTAT = 0xff;
00148 
00149     // USB Interrupt Enablers
00150     USB0->INTEN |= USB_INTEN_TOKDNEEN_MASK |
00151                    USB_INTEN_SOFTOKEN_MASK |
00152                    USB_INTEN_ERROREN_MASK  |
00153                    USB_INTEN_USBRSTEN_MASK;
00154 
00155     // Disable weak pull downs
00156     USB0->USBCTRL &= ~(USB_USBCTRL_PDE_MASK | USB_USBCTRL_SUSP_MASK);
00157 
00158     USB0->USBTRC0 |= 0x40;
00159 }
00160 
00161 USBHAL::~USBHAL(void) { }
00162 
00163 void USBHAL::connect(void) {
00164     // enable USB
00165     USB0->CTL |= USB_CTL_USBENSOFEN_MASK;
00166     // Pull up enable
00167     USB0->CONTROL |= USB_CONTROL_DPPULLUPNONOTG_MASK;
00168 }
00169 
00170 void USBHAL::disconnect(void) {
00171     // disable USB
00172     USB0->CTL &= ~USB_CTL_USBENSOFEN_MASK;
00173     // Pull up disable
00174     USB0->CONTROL &= ~USB_CONTROL_DPPULLUPNONOTG_MASK;
00175 
00176     //Free buffers if required:
00177     for (int i = 0; i<(NUMBER_OF_PHYSICAL_ENDPOINTS - 2) * 2; i++) {
00178         free(endpoint_buffer[i]);
00179         endpoint_buffer[i] = NULL;
00180     }
00181     free(endpoint_buffer_iso[2]);
00182     endpoint_buffer_iso[2] = NULL;
00183     free(endpoint_buffer_iso[0]);
00184     endpoint_buffer_iso[0] = NULL;
00185 }
00186 
00187 void USBHAL::configureDevice(void) {
00188     // not needed
00189 }
00190 
00191 void USBHAL::unconfigureDevice(void) {
00192     // not needed
00193 }
00194 
00195 void USBHAL::setAddress(uint8_t address) {
00196     // we don't set the address now otherwise the usb controller does not ack
00197     // we set a flag instead
00198     // see usbisr when an IN token is received
00199     set_addr = 1;
00200     addr = address;
00201 }
00202 
00203 bool USBHAL::realiseEndpoint(uint8_t endpoint, uint32_t maxPacket, uint32_t flags) {
00204     uint32_t handshake_flag = 0;
00205     uint8_t * buf;
00206 
00207     if (endpoint > NUMBER_OF_PHYSICAL_ENDPOINTS - 1) {
00208         return false;
00209     }
00210 
00211     uint32_t log_endpoint = PHY_TO_LOG(endpoint);
00212 
00213     if ((flags & ISOCHRONOUS) == 0) {
00214         handshake_flag = USB_ENDPT_EPHSHK_MASK;
00215         if (IN_EP(endpoint)) {
00216             if (endpoint_buffer[EP_BDT_IDX(log_endpoint, TX, ODD)] == NULL)
00217                 endpoint_buffer[EP_BDT_IDX(log_endpoint, TX, ODD)] = (uint8_t *) malloc (64*2);
00218             buf = &endpoint_buffer[EP_BDT_IDX(log_endpoint, TX, ODD)][0];
00219         } else {
00220             if (endpoint_buffer[EP_BDT_IDX(log_endpoint, RX, ODD)] == NULL)
00221                 endpoint_buffer[EP_BDT_IDX(log_endpoint, RX, ODD)] = (uint8_t *) malloc (64*2);
00222             buf = &endpoint_buffer[EP_BDT_IDX(log_endpoint, RX, ODD)][0];
00223         }
00224     } else {
00225         if (IN_EP(endpoint)) {
00226             if (endpoint_buffer_iso[2] == NULL)
00227                 endpoint_buffer_iso[2] = (uint8_t *) malloc (1023*2);
00228             buf = &endpoint_buffer_iso[2][0];
00229         } else {
00230             if (endpoint_buffer_iso[0] == NULL)
00231                 endpoint_buffer_iso[0] = (uint8_t *) malloc (1023*2);
00232             buf = &endpoint_buffer_iso[0][0];
00233         }
00234     }
00235 
00236     // IN endpt -> device to host (TX)
00237     if (IN_EP(endpoint)) {
00238         USB0->ENDPOINT[log_endpoint].ENDPT |= handshake_flag |        // ep handshaking (not if iso endpoint)
00239                                               USB_ENDPT_EPTXEN_MASK;  // en TX (IN) tran
00240         bdt[EP_BDT_IDX(log_endpoint, TX, ODD )].address = (uint32_t) buf;
00241         bdt[EP_BDT_IDX(log_endpoint, TX, EVEN)].address = 0;
00242     }
00243     // OUT endpt -> host to device (RX)
00244     else {
00245         USB0->ENDPOINT[log_endpoint].ENDPT |= handshake_flag |        // ep handshaking (not if iso endpoint)
00246                                               USB_ENDPT_EPRXEN_MASK;  // en RX (OUT) tran.
00247         bdt[EP_BDT_IDX(log_endpoint, RX, ODD )].byte_count = maxPacket;
00248         bdt[EP_BDT_IDX(log_endpoint, RX, ODD )].address    = (uint32_t) buf;
00249         bdt[EP_BDT_IDX(log_endpoint, RX, ODD )].info       = BD_OWN_MASK | BD_DTS_MASK;
00250         bdt[EP_BDT_IDX(log_endpoint, RX, EVEN)].info       = 0;
00251     }
00252 
00253     Data1 |= (1 << endpoint);
00254 
00255     return true;
00256 }
00257 
00258 // read setup packet
00259 void USBHAL::EP0setup(uint8_t *buffer) {
00260     uint32_t sz;
00261     endpointReadResult(EP0OUT, buffer, &sz);
00262 }
00263 
00264 void USBHAL::EP0readStage(void) {
00265     Data1 &= ~1UL;  // set DATA0
00266     bdt[0].info = (BD_DTS_MASK | BD_OWN_MASK);
00267 }
00268 
00269 void USBHAL::EP0read(void) {
00270     uint32_t idx = EP_BDT_IDX(PHY_TO_LOG(EP0OUT), RX, 0);
00271     bdt[idx].byte_count = MAX_PACKET_SIZE_EP0;
00272 }
00273 
00274 uint32_t USBHAL::EP0getReadResult(uint8_t *buffer) {
00275     uint32_t sz;
00276     endpointReadResult(EP0OUT, buffer, &sz);
00277     return sz;
00278 }
00279 
00280 void USBHAL::EP0write(uint8_t *buffer, uint32_t size) {
00281     endpointWrite(EP0IN, buffer, size);
00282 }
00283 
00284 void USBHAL::EP0getWriteResult(void) {
00285 }
00286 
00287 void USBHAL::EP0stall(void) {
00288     stallEndpoint(EP0OUT);
00289 }
00290 
00291 EP_STATUS USBHAL::endpointRead(uint8_t endpoint, uint32_t maximumSize) {
00292     endpoint = PHY_TO_LOG(endpoint);
00293     uint32_t idx = EP_BDT_IDX(endpoint, RX, 0);
00294     bdt[idx].byte_count = maximumSize;
00295     return EP_PENDING;
00296 }
00297 
00298 EP_STATUS USBHAL::endpointReadResult(uint8_t endpoint, uint8_t * buffer, uint32_t *bytesRead) {
00299     uint32_t n, sz, idx, setup = 0;
00300     uint8_t not_iso;
00301     uint8_t * ep_buf;
00302 
00303     uint32_t log_endpoint = PHY_TO_LOG(endpoint);
00304 
00305     if (endpoint > NUMBER_OF_PHYSICAL_ENDPOINTS - 1) {
00306         return EP_INVALID;
00307     }
00308 
00309     // if read on a IN endpoint -> error
00310     if (IN_EP(endpoint)) {
00311         return EP_INVALID;
00312     }
00313 
00314     idx = EP_BDT_IDX(log_endpoint, RX, 0);
00315     sz  = bdt[idx].byte_count;
00316     not_iso = USB0->ENDPOINT[log_endpoint].ENDPT & USB_ENDPT_EPHSHK_MASK;
00317 
00318     //for isochronous endpoint, we don't wait an interrupt
00319     if ((log_endpoint != 0) && not_iso && !(epComplete & EP(endpoint))) {
00320         return EP_PENDING;
00321     }
00322 
00323     if ((log_endpoint == 0) && (TOK_PID(idx) == SETUP_TOKEN)) {
00324         setup = 1;
00325     }
00326 
00327     // non iso endpoint
00328     if (not_iso) {
00329         ep_buf = endpoint_buffer[idx];
00330     } else {
00331         ep_buf = endpoint_buffer_iso[0];
00332     }
00333 
00334     for (n = 0; n < sz; n++) {
00335         buffer[n] = ep_buf[n];
00336     }
00337 
00338     if (((Data1 >> endpoint) & 1) == ((bdt[idx].info >> 6) & 1)) {
00339         if (setup && (buffer[6] == 0))  // if no setup data stage,
00340             Data1 &= ~1UL;              // set DATA0
00341         else
00342             Data1 ^= (1 << endpoint);
00343     }
00344 
00345     if (((Data1 >> endpoint) & 1)) {
00346         bdt[idx].info = BD_DTS_MASK | BD_DATA01_MASK | BD_OWN_MASK;
00347     }
00348     else {
00349         bdt[idx].info = BD_DTS_MASK | BD_OWN_MASK;
00350     }
00351 
00352     USB0->CTL &= ~USB_CTL_TXSUSPENDTOKENBUSY_MASK;
00353     *bytesRead = sz;
00354 
00355     epComplete &= ~EP(endpoint);
00356     return EP_COMPLETED;
00357 }
00358 
00359 EP_STATUS USBHAL::endpointWrite(uint8_t endpoint, uint8_t *data, uint32_t size) {
00360     uint32_t idx, n;
00361     uint8_t * ep_buf;
00362 
00363     if (endpoint > NUMBER_OF_PHYSICAL_ENDPOINTS - 1) {
00364         return EP_INVALID;
00365     }
00366 
00367     // if write on a OUT endpoint -> error
00368     if (OUT_EP(endpoint)) {
00369         return EP_INVALID;
00370     }
00371 
00372     idx = EP_BDT_IDX(PHY_TO_LOG(endpoint), TX, 0);
00373     bdt[idx].byte_count = size;
00374 
00375 
00376     // non iso endpoint
00377     if (USB0->ENDPOINT[PHY_TO_LOG(endpoint)].ENDPT & USB_ENDPT_EPHSHK_MASK) {
00378         ep_buf = endpoint_buffer[idx];
00379     } else {
00380         ep_buf = endpoint_buffer_iso[2];
00381     }
00382 
00383     for (n = 0; n < size; n++) {
00384         ep_buf[n] = data[n];
00385     }
00386 
00387     if ((Data1 >> endpoint) & 1) {
00388         bdt[idx].info = BD_OWN_MASK | BD_DTS_MASK;
00389     } else {
00390         bdt[idx].info = BD_OWN_MASK | BD_DTS_MASK | BD_DATA01_MASK;
00391     }
00392 
00393     Data1 ^= (1 << endpoint);
00394 
00395     return EP_PENDING;
00396 }
00397 
00398 EP_STATUS USBHAL::endpointWriteResult(uint8_t endpoint) {
00399     if (epComplete & EP(endpoint)) {
00400         epComplete &= ~EP(endpoint);
00401         return EP_COMPLETED;
00402     }
00403 
00404     return EP_PENDING;
00405 }
00406 
00407 void USBHAL::stallEndpoint(uint8_t endpoint) {
00408     USB0->ENDPOINT[PHY_TO_LOG(endpoint)].ENDPT |= USB_ENDPT_EPSTALL_MASK;
00409 }
00410 
00411 void USBHAL::unstallEndpoint(uint8_t endpoint) {
00412     USB0->ENDPOINT[PHY_TO_LOG(endpoint)].ENDPT &= ~USB_ENDPT_EPSTALL_MASK;
00413 }
00414 
00415 bool USBHAL::getEndpointStallState(uint8_t endpoint) {
00416     uint8_t stall = (USB0->ENDPOINT[PHY_TO_LOG(endpoint)].ENDPT & USB_ENDPT_EPSTALL_MASK);
00417     return (stall) ? true : false;
00418 }
00419 
00420 void USBHAL::remoteWakeup(void) {
00421     // [TODO]
00422 }
00423 
00424 
00425 void USBHAL::_usbisr(void) {
00426     instance->usbisr();
00427 }
00428 
00429 
00430 void USBHAL::usbisr(void) {
00431     uint8_t i;
00432     uint8_t istat = USB0->ISTAT;
00433 
00434     // reset interrupt
00435     if (istat & USB_ISTAT_USBRST_MASK) {
00436         // disable all endpt
00437         for(i = 0; i < 16; i++) {
00438             USB0->ENDPOINT[i].ENDPT = 0x00;
00439         }
00440 
00441         // enable control endpoint
00442         realiseEndpoint(EP0OUT, MAX_PACKET_SIZE_EP0, 0);
00443         realiseEndpoint(EP0IN, MAX_PACKET_SIZE_EP0, 0);
00444 
00445         Data1 = 0x55555555;
00446         USB0->CTL |=  USB_CTL_ODDRST_MASK;
00447 
00448         USB0->ISTAT   =  0xFF;  // clear all interrupt status flags
00449         USB0->ERRSTAT =  0xFF;  // clear all error flags
00450         USB0->ERREN   =  0xFF;  // enable error interrupt sources
00451         USB0->ADDR    =  0x00;  // set default address
00452 
00453         // reset bus for USBDevice layer
00454         busReset();
00455 
00456         return;
00457     }
00458 
00459     // resume interrupt
00460     if (istat & USB_ISTAT_RESUME_MASK) {
00461         USB0->ISTAT = USB_ISTAT_RESUME_MASK;
00462     }
00463 
00464     // SOF interrupt
00465     if (istat & USB_ISTAT_SOFTOK_MASK) {
00466         USB0->ISTAT = USB_ISTAT_SOFTOK_MASK;
00467         // SOF event, read frame number
00468         SOF(frameNumber());
00469     }
00470 
00471     // stall interrupt
00472     if (istat & 1<<7) {
00473         if (USB0->ENDPOINT[0].ENDPT & USB_ENDPT_EPSTALL_MASK)
00474             USB0->ENDPOINT[0].ENDPT &= ~USB_ENDPT_EPSTALL_MASK;
00475         USB0->ISTAT |= USB_ISTAT_STALL_MASK;
00476     }
00477 
00478     // token interrupt
00479     if (istat & 1<<3) {
00480         uint32_t num  = (USB0->STAT >> 4) & 0x0F;
00481         uint32_t dir  = (USB0->STAT >> 3) & 0x01;
00482         uint32_t ev_odd = (USB0->STAT >> 2) & 0x01;
00483 
00484         // setup packet
00485         if ((num == 0) && (TOK_PID((EP_BDT_IDX(num, dir, ev_odd))) == SETUP_TOKEN)) {
00486             Data1 &= ~0x02;
00487             bdt[EP_BDT_IDX(0, TX, EVEN)].info &= ~BD_OWN_MASK;
00488             bdt[EP_BDT_IDX(0, TX, ODD)].info  &= ~BD_OWN_MASK;
00489 
00490             // EP0 SETUP event (SETUP data received)
00491             EP0setupCallback();
00492 
00493         } else {
00494             // OUT packet
00495             if (TOK_PID((EP_BDT_IDX(num, dir, ev_odd))) == OUT_TOKEN) {
00496                 if (num == 0)
00497                     EP0out();
00498                 else {
00499                     epComplete |= (1 << EP(num));
00500                     if ((instance->*(epCallback[EP(num) - 2]))()) {
00501                         epComplete &= ~(1 << EP(num));
00502                     }
00503                 }
00504             }
00505 
00506             // IN packet
00507             if (TOK_PID((EP_BDT_IDX(num, dir, ev_odd))) == IN_TOKEN) {
00508                 if (num == 0) {
00509                     EP0in();
00510                     if (set_addr == 1) {
00511                         USB0->ADDR = addr & 0x7F;
00512                         set_addr = 0;
00513                     }
00514                 }
00515                 else {
00516                     epComplete |= (1 << (EP(num) + 1));
00517                     if ((instance->*(epCallback[EP(num) + 1 - 2]))()) {
00518                         epComplete &= ~(1 << (EP(num) + 1));
00519                     }
00520                 }
00521             }
00522         }
00523 
00524         USB0->ISTAT = USB_ISTAT_TOKDNE_MASK;
00525     }
00526 
00527     // sleep interrupt
00528     if (istat & 1<<4) {
00529         USB0->ISTAT |= USB_ISTAT_SLEEP_MASK;
00530     }
00531 
00532     // error interrupt
00533     if (istat & USB_ISTAT_ERROR_MASK) {
00534         USB0->ERRSTAT = 0xFF;
00535         USB0->ISTAT |= USB_ISTAT_ERROR_MASK;
00536     }
00537 }
00538 
00539 
00540 #endif