Text fixes

2 files changed, 12 insertions, 541 deletions

diff --git a/ports/stm32f4/common-hal/busio/SPI.c b/ports/stm32f4/common-hal/busio/SPI.c
index a8b919984..dfb436fb9 100644
--- a/ports/stm32f4/common-hal/busio/SPI.c
+++ b/ports/stm32f4/common-hal/busio/SPI.c
@@ -34,215 +34,24 @@
 void common_hal_busio_spi_construct(busio_spi_obj_t *self,
          const mcu_pin_obj_t * clock, const mcu_pin_obj_t * mosi,
          const mcu_pin_obj_t * miso) {
-    // Sercom* sercom = NULL;
-    // uint8_t sercom_index;
-    // uint32_t clock_pinmux = 0;
-    // bool mosi_none = mosi == mp_const_none || mosi == NULL;
-    // bool miso_none = miso == mp_const_none || miso == NULL;
-    // uint32_t mosi_pinmux = 0;
-    // uint32_t miso_pinmux = 0;
-    // uint8_t clock_pad = 0;
-    // uint8_t mosi_pad = 0;
-    // uint8_t miso_pad = 0;
-    // uint8_t dopo = 255;
-
-    // // Special case for SAMR boards.
-    // #ifdef PIN_PC19
-    // if (miso == &pin_PC19) {
-    //     if (mosi == &pin_PB30 && clock == &pin_PC18) {
-    //         sercom = SERCOM4;
-    //         sercom_index = 4;
-    //         clock_pinmux = MUX_F;
-    //         mosi_pinmux = MUX_F;
-    //         miso_pinmux = MUX_F;
-    //         clock_pad = 3;
-    //         mosi_pad = 2;
-    //         miso_pad = 0;
-    //         dopo = samd_peripherals_get_spi_dopo(clock_pad, mosi_pad);
-    //     }
-    //     // Error, leave SERCOM unset to throw an exception later.
-    // } else {
-    // #endif
-    // for (int i = 0; i < NUM_SERCOMS_PER_PIN; i++) {
-    //     sercom_index = clock->sercom[i].index; // 2 for SERCOM2, etc.
-    //     if (sercom_index >= SERCOM_INST_NUM) {
-    //         continue;
-    //     }
-    //     Sercom* potential_sercom = sercom_insts[sercom_index];
-    //     if (
-    //     #if defined(MICROPY_HW_APA102_SCK) && defined(MICROPY_HW_APA102_MOSI) && !defined(CIRCUITPY_BITBANG_APA102)
-    //         (potential_sercom->SPI.CTRLA.bit.ENABLE != 0 &&
-    //          potential_sercom != status_apa102.spi_desc.dev.prvt &&
-    //          !apa102_sck_in_use)) {
-    //     #else
-    //         potential_sercom->SPI.CTRLA.bit.ENABLE != 0) {
-    //     #endif
-    //         continue;
-    //     }
-    //     clock_pinmux = PINMUX(clock->number, (i == 0) ? MUX_C : MUX_D);
-    //     clock_pad = clock->sercom[i].pad;
-    //     if (!samd_peripherals_valid_spi_clock_pad(clock_pad)) {
-    //         continue;
-    //     }
-    //     for (int j = 0; j < NUM_SERCOMS_PER_PIN; j++) {
-    //         if (!mosi_none) {
-    //             if (sercom_index == mosi->sercom[j].index) {
-    //                 mosi_pinmux = PINMUX(mosi->number, (j == 0) ? MUX_C : MUX_D);
-    //                 mosi_pad = mosi->sercom[j].pad;
-    //                 dopo = samd_peripherals_get_spi_dopo(clock_pad, mosi_pad);
-    //                 if (dopo > 0x3) {
-    //                     continue;  // pad combination not possible
-    //                 }
-    //                 if (miso_none) {
-    //                     sercom = potential_sercom;
-    //                     break;
-    //                 }
-    //             } else {
-    //                 continue;
-    //             }
-    //         }
-    //         if (!miso_none) {
-    //             for (int k = 0; k < NUM_SERCOMS_PER_PIN; k++) {
-    //                 if (sercom_index == miso->sercom[k].index) {
-    //                     miso_pinmux = PINMUX(miso->number, (k == 0) ? MUX_C : MUX_D);
-    //                     miso_pad = miso->sercom[k].pad;
-    //                     sercom = potential_sercom;
-    //                     break;
-    //                 }
-    //             }
-    //         }
-    //         if (sercom != NULL) {
-    //             break;
-    //         }
-    //     }
-    //     if (sercom != NULL) {
-    //         break;
-    //     }
-    // }
-    // #ifdef PIN_PC19
-    // }
-    // #endif
-    // if (sercom == NULL) {
-    //     mp_raise_ValueError(translate("Invalid pins"));
-    // }
-
-    // // Set up SPI clocks on SERCOM.
-    // samd_peripherals_sercom_clock_init(sercom, sercom_index);
-
-    // #if defined(MICROPY_HW_APA102_SCK) && defined(MICROPY_HW_APA102_MOSI) && !defined(CIRCUITPY_BITBANG_APA102)
-    // // if we're re-using the dotstar sercom, make sure it is disabled or the init will fail out
-    // hri_sercomspi_clear_CTRLA_ENABLE_bit(sercom);
-    // #endif
-    // if (spi_m_sync_init(&self->spi_desc, sercom) != ERR_NONE) {
-    //     mp_raise_OSError(MP_EIO);
-    // }
-
-    // // Pads must be set after spi_m_sync_init(), which uses default values from
-    // // the prototypical SERCOM.
-    // hri_sercomspi_write_CTRLA_DOPO_bf(sercom, dopo);
-    // hri_sercomspi_write_CTRLA_DIPO_bf(sercom, miso_pad);
-
-    // // Always start at 250khz which is what SD cards need. They are sensitive to
-    // // SPI bus noise before they are put into SPI mode.
-    // uint8_t baud_value = samd_peripherals_spi_baudrate_to_baud_reg_value(250000);
-    // if (spi_m_sync_set_baudrate(&self->spi_desc, baud_value) != ERR_NONE) {
-    //     // spi_m_sync_set_baudrate does not check for validity, just whether the device is
-    //     // busy or not
-    //     mp_raise_OSError(MP_EIO);
-    // }
-
-    // gpio_set_pin_direction(clock->number, GPIO_DIRECTION_OUT);
-    // gpio_set_pin_pull_mode(clock->number, GPIO_PULL_OFF);
-    // gpio_set_pin_function(clock->number, clock_pinmux);
-    // claim_pin(clock);
-    // self->clock_pin = clock->number;
-
-    // if (mosi_none) {
-    //     self->MOSI_pin = NO_PIN;
-    // } else {
-    //     gpio_set_pin_direction(mosi->number, GPIO_DIRECTION_OUT);
-    //     gpio_set_pin_pull_mode(mosi->number, GPIO_PULL_OFF);
-    //     gpio_set_pin_function(mosi->number, mosi_pinmux);
-    //     self->MOSI_pin = mosi->number;
-    //     claim_pin(mosi);
-    // }
-
-    // if (miso_none) {
-    //     self->MISO_pin = NO_PIN;
-    // } else {
-    //     gpio_set_pin_direction(miso->number, GPIO_DIRECTION_IN);
-    //     gpio_set_pin_pull_mode(miso->number, GPIO_PULL_OFF);
-    //     gpio_set_pin_function(miso->number, miso_pinmux);
-    //     self->MISO_pin = miso->number;
-    //     claim_pin(miso);
-    // }
-
-    // spi_m_sync_enable(&self->spi_desc);
 }
 
 void common_hal_busio_spi_never_reset(busio_spi_obj_t *self) {
-    // never_reset_sercom(self->spi_desc.dev.prvt);
-
-    // never_reset_pin_number(self->clock_pin);
-    // never_reset_pin_number(self->MOSI_pin);
-    // never_reset_pin_number(self->MISO_pin);
 }
 
 bool common_hal_busio_spi_deinited(busio_spi_obj_t *self) {
-    //return self->clock_pin == NO_PIN;
 }
 
 void common_hal_busio_spi_deinit(busio_spi_obj_t *self) {
-    // if (common_hal_busio_spi_deinited(self)) {
-    //     return;
-    // }
-    // allow_reset_sercom(self->spi_desc.dev.prvt);
-
-    // spi_m_sync_disable(&self->spi_desc);
-    // spi_m_sync_deinit(&self->spi_desc);
-    // reset_pin_number(self->clock_pin);
-    // reset_pin_number(self->MOSI_pin);
-    // reset_pin_number(self->MISO_pin);
-    // self->clock_pin = NO_PIN;
 }
 
 bool common_hal_busio_spi_configure(busio_spi_obj_t *self,
          uint32_t baudrate, uint8_t polarity, uint8_t phase, uint8_t bits) {
-    // uint8_t baud_reg_value = samd_peripherals_spi_baudrate_to_baud_reg_value(baudrate);
-
-    // void * hw = self->spi_desc.dev.prvt;
-    // // If the settings are already what we want then don't reset them.
-    // if (hri_sercomspi_get_CTRLA_CPHA_bit(hw) == phase &&
-    //     hri_sercomspi_get_CTRLA_CPOL_bit(hw) == polarity &&
-    //     hri_sercomspi_read_CTRLB_CHSIZE_bf(hw) == ((uint32_t)bits - 8) &&
-    //     hri_sercomspi_read_BAUD_BAUD_bf(hw) == baud_reg_value) {
-    //     return true;
-    // }
-
-    // // Disable, set values (most or all are enable-protected), and re-enable.
-    // spi_m_sync_disable(&self->spi_desc);
-    // hri_sercomspi_wait_for_sync(hw, SERCOM_SPI_SYNCBUSY_MASK);
-
-    // hri_sercomspi_write_CTRLA_CPHA_bit(hw, phase);
-    // hri_sercomspi_write_CTRLA_CPOL_bit(hw, polarity);
-    // hri_sercomspi_write_CTRLB_CHSIZE_bf(hw, bits - 8);
-    // hri_sercomspi_write_BAUD_BAUD_bf(hw, baud_reg_value);
-    // hri_sercomspi_wait_for_sync(hw, SERCOM_SPI_SYNCBUSY_MASK);
-
-    // spi_m_sync_enable(&self->spi_desc);
-    // hri_sercomspi_wait_for_sync(hw, SERCOM_SPI_SYNCBUSY_MASK);
-
      return true;
 }
 
 bool common_hal_busio_spi_try_lock(busio_spi_obj_t *self) {
     bool grabbed_lock = false;
-    // CRITICAL_SECTION_ENTER()
-    //     if (!self->has_lock) {
-    //         grabbed_lock = true;
-    //         self->has_lock = true;
-    //     }
-    // CRITICAL_SECTION_LEAVE();
     return grabbed_lock;
 }
 
@@ -256,66 +65,25 @@ void common_hal_busio_spi_unlock(busio_spi_obj_t *self) {
 
 bool common_hal_busio_spi_write(busio_spi_obj_t *self,
         const uint8_t *data, size_t len) {
-    // if (len == 0) {
-    //     return true;
-    // }
-    // int32_t status;
-    // if (len >= 16) {
-    //     status = sercom_dma_write(self->spi_desc.dev.prvt, data, len);
-    // } else {
-    //     struct io_descriptor *spi_io;
-    //     spi_m_sync_get_io_descriptor(&self->spi_desc, &spi_io);
-    //     status = spi_io->write(spi_io, data, len);
-    // }
-    return 0;//status >= 0; // Status is number of chars read or an error code < 0.
+    return 0;
 }
 
 bool common_hal_busio_spi_read(busio_spi_obj_t *self,
         uint8_t *data, size_t len, uint8_t write_value) {
-    // if (len == 0) {
-    //     return true;
-    // }
-    // int32_t status;
-    // if (len >= 16) {
-    //     status = sercom_dma_read(self->spi_desc.dev.prvt, data, len, write_value);
-    // } else {
-    //     self->spi_desc.dev.dummy_byte = write_value;
-
-    //     struct io_descriptor *spi_io;
-    //     spi_m_sync_get_io_descriptor(&self->spi_desc, &spi_io);
-
-    //     status = spi_io->read(spi_io, data, len);
-    // }
-    return 0;//status >= 0; // Status is number of chars read or an error code < 0.
+    return 0;
 }
 
 bool common_hal_busio_spi_transfer(busio_spi_obj_t *self, uint8_t *data_out, uint8_t *data_in, size_t len) {
-    // if (len == 0) {
-    //     return true;
-    // }
-    // int32_t status;
-    // if (len >= 16) {
-    //     status = sercom_dma_transfer(self->spi_desc.dev.prvt, data_out, data_in, len);
-    // } else {
-    //     struct spi_xfer xfer;
-    //     xfer.txbuf = data_out;
-    //     xfer.rxbuf = data_in;
-    //     xfer.size = len;
-    //     status = spi_m_sync_transfer(&self->spi_desc, &xfer);
-    // }
-    return 0;//status >= 0; // Status is number of chars read or an error code < 0.
+    return 0;
 }
 
 uint32_t common_hal_busio_spi_get_frequency(busio_spi_obj_t* self) {
-    return 0;//samd_peripherals_spi_baud_reg_value_to_baudrate(hri_sercomspi_read_BAUD_reg(self->spi_desc.dev.prvt));
+    return 0;
 }
 
 uint8_t common_hal_busio_spi_get_phase(busio_spi_obj_t* self) {
-    //void * hw = self->spi_desc.dev.prvt;
-    return 0;//hri_sercomspi_get_CTRLA_CPHA_bit(hw);
+    return 0;
 }
 
 uint8_t common_hal_busio_spi_get_polarity(busio_spi_obj_t* self) {
-    //void * hw = self->spi_desc.dev.prvt;
-    return 0;//hri_sercomspi_get_CTRLA_CPOL_bit(hw);
-}
+    return 0;
diff --git a/ports/stm32f4/common-hal/busio/UART.c b/ports/stm32f4/common-hal/busio/UART.c
index 86035c3ba..32653ab8b 100644
--- a/ports/stm32f4/common-hal/busio/UART.c
+++ b/ports/stm32f4/common-hal/busio/UART.c
@@ -41,336 +41,39 @@ void common_hal_busio_uart_construct(busio_uart_obj_t *self,
         const mcu_pin_obj_t * tx, const mcu_pin_obj_t * rx, uint32_t baudrate,
         uint8_t bits, uart_parity_t parity, uint8_t stop, mp_float_t timeout,
         uint16_t receiver_buffer_size) {
-
-    // Sercom* sercom = NULL;
-    // uint8_t sercom_index = 255; // Unset index
-    // uint32_t rx_pinmux = 0;
-    // uint8_t rx_pad = 255; // Unset pad
-    // uint32_t tx_pinmux = 0;
-    // uint8_t tx_pad = 255; // Unset pad
-
-    // if (bits > 8) {
-    //     mp_raise_NotImplementedError(translate("bytes > 8 bits not supported"));
-    // }
-
-    // bool have_tx = tx != mp_const_none;
-    // bool have_rx = rx != mp_const_none;
-    // if (!have_tx && !have_rx) {
-    //     mp_raise_ValueError(translate("tx and rx cannot both be None"));
-    // }
-
-    // self->baudrate = baudrate;
-    // self->character_bits = bits;
-    // self->timeout_ms = timeout * 1000;
-
-    // // This assignment is only here because the usart_async routines take a *const argument.
-    // struct usart_async_descriptor * const usart_desc_p = (struct usart_async_descriptor * const) &self->usart_desc;
-
-    // for (int i = 0; i < NUM_SERCOMS_PER_PIN; i++) {
-    //     Sercom* potential_sercom = NULL;
-    //     if (have_tx) {
-    //         sercom_index = tx->sercom[i].index;
-    //         if (sercom_index >= SERCOM_INST_NUM) {
-    //             continue;
-    //         }
-    //         potential_sercom = sercom_insts[sercom_index];
-    //         if (potential_sercom->USART.CTRLA.bit.ENABLE != 0 ||
-    //             !(tx->sercom[i].pad == 0 ||
-    //               tx->sercom[i].pad == 2)) {
-    //             continue;
-    //         }
-    //         tx_pinmux = PINMUX(tx->number, (i == 0) ? MUX_C : MUX_D);
-    //         tx_pad = tx->sercom[i].pad;
-    //         if (rx == mp_const_none) {
-    //             sercom = potential_sercom;
-    //             break;
-    //         }
-    //     }
-    //     for (int j = 0; j < NUM_SERCOMS_PER_PIN; j++) {
-    //         if (((!have_tx && rx->sercom[j].index < SERCOM_INST_NUM &&
-    //               sercom_insts[rx->sercom[j].index]->USART.CTRLA.bit.ENABLE == 0) ||
-    //              sercom_index == rx->sercom[j].index) &&
-    //             rx->sercom[j].pad != tx_pad) {
-    //             rx_pinmux = PINMUX(rx->number, (j == 0) ? MUX_C : MUX_D);
-    //             rx_pad = rx->sercom[j].pad;
-    //             sercom = sercom_insts[rx->sercom[j].index];
-    //             sercom_index = rx->sercom[j].index;
-    //             break;
-    //         }
-    //     }
-    //     if (sercom != NULL) {
-    //         break;
-    //     }
-    // }
-    // if (sercom == NULL) {
-    //     mp_raise_ValueError(translate("Invalid pins"));
-    // }
-    // if (!have_tx) {
-    //     tx_pad = 0;
-    //     if (rx_pad == 0) {
-    //         tx_pad = 2;
-    //     }
-    // }
-    // if (!have_rx) {
-    //     rx_pad = (tx_pad + 1) % 4;
-    // }
-
-    // // Set up clocks on SERCOM.
-    // samd_peripherals_sercom_clock_init(sercom, sercom_index);
-
-    // if (rx && receiver_buffer_size > 0) {
-    //     self->buffer_length = receiver_buffer_size;
-    //     // Initially allocate the UART's buffer in the long-lived part of the
-    //     // heap.  UARTs are generally long-lived objects, but the "make long-
-    //     // lived" machinery is incapable of moving internal pointers like
-    //     // self->buffer, so do it manually.  (However, as long as internal
-    //     // pointers like this are NOT moved, allocating the buffer
-    //     // in the long-lived pool is not strictly necessary)
-    //     self->buffer = (uint8_t *) gc_alloc(self->buffer_length * sizeof(uint8_t), false, true);
-    //     if (self->buffer == NULL) {
-    //         common_hal_busio_uart_deinit(self);
-    //         mp_raise_msg(&mp_type_MemoryError, translate("Failed to allocate RX buffer"));
-    //     }
-    // } else {
-    //     self->buffer_length = 0;
-    //     self->buffer = NULL;
-    // }
-
-    // if (usart_async_init(usart_desc_p, sercom, self->buffer, self->buffer_length, NULL) != ERR_NONE) {
-    //     mp_raise_ValueError(translate("Could not initialize UART"));
-    // }
-
-    // // usart_async_init() sets a number of defaults based on a prototypical SERCOM
-    // // which don't necessarily match what we need. After calling it, set the values
-    // // specific to this instantiation of UART.
-
-    // // Set pads computed for this SERCOM.
-    // // TXPO:
-    // // 0x0: TX pad 0; no RTS/CTS
-    // // 0x1: TX pad 2; no RTS/CTS
-    // // 0x2: TX pad 0; RTS: pad 2, CTS: pad 3 (not used by us right now)
-    // // So divide by 2 to map pad to value.
-    // // RXPO:
-    // // 0x0: RX pad 0
-    // // 0x1: RX pad 1
-    // // 0x2: RX pad 2
-    // // 0x3: RX pad 3
-
-    // // Doing a group mask and set of the registers saves 60 bytes over setting the bitfields individually.
-
-    // sercom->USART.CTRLA.reg &= ~(SERCOM_USART_CTRLA_TXPO_Msk |
-    //                              SERCOM_USART_CTRLA_RXPO_Msk |
-    //                              SERCOM_USART_CTRLA_FORM_Msk);
-    // sercom->USART.CTRLA.reg |= SERCOM_USART_CTRLA_TXPO(tx_pad / 2) |
-    //                            SERCOM_USART_CTRLA_RXPO(rx_pad) |
-    //                            (parity == PARITY_NONE ? 0 : SERCOM_USART_CTRLA_FORM(1));
-
-    // // Enable tx and/or rx based on whether the pins were specified.
-    // // CHSIZE is 0 for 8 bits, 5, 6, 7 for 5, 6, 7 bits. 1 for 9 bits, but we don't support that.
-    // sercom->USART.CTRLB.reg &= ~(SERCOM_USART_CTRLB_TXEN |
-    //                              SERCOM_USART_CTRLB_RXEN |
-    //                              SERCOM_USART_CTRLB_PMODE |
-    //                              SERCOM_USART_CTRLB_SBMODE |
-    //                              SERCOM_USART_CTRLB_CHSIZE_Msk);
-    // sercom->USART.CTRLB.reg |= (have_tx ? SERCOM_USART_CTRLB_TXEN : 0) |
-    //                            (have_rx ? SERCOM_USART_CTRLB_RXEN : 0) |
-    //                            (parity == PARITY_ODD ? SERCOM_USART_CTRLB_PMODE : 0) |
-    //                            (stop > 1 ? SERCOM_USART_CTRLB_SBMODE : 0) |
-    //                            SERCOM_USART_CTRLB_CHSIZE(bits % 8);
-
-    // // Set baud rate
-    // common_hal_busio_uart_set_baudrate(self, baudrate);
-
-    // // Turn on rx interrupt handling. The UART async driver has its own set of internal callbacks,
-    // // which are set up by uart_async_init(). These in turn can call user-specified callbacks.
-    // // In fact, the actual interrupts are not enabled unless we set up a user-specified callback.
-    // // This is confusing. It's explained in the Atmel START User Guide -> Implementation Description ->
-    // // Different read function behavior in some asynchronous drivers. As of this writing:
-    // // http://start.atmel.com/static/help/index.html?GUID-79201A5A-226F-4FBB-B0B8-AB0BE0554836
-    // // Look at the ASFv4 code example for async USART.
-    // usart_async_register_callback(usart_desc_p, USART_ASYNC_RXC_CB, usart_async_rxc_callback);
-
-
-    // if (have_tx) {
-    //     gpio_set_pin_direction(tx->number, GPIO_DIRECTION_OUT);
-    //     gpio_set_pin_pull_mode(tx->number, GPIO_PULL_OFF);
-    //     gpio_set_pin_function(tx->number, tx_pinmux);
-    //     self->tx_pin  = tx->number;
-    //     claim_pin(tx);
-    // } else {
-    //     self->tx_pin = NO_PIN;
-    // }
-
-    // if (have_rx) {
-    //     gpio_set_pin_direction(rx->number, GPIO_DIRECTION_IN);
-    //     gpio_set_pin_pull_mode(rx->number, GPIO_PULL_OFF);
-    //     gpio_set_pin_function(rx->number, rx_pinmux);
-    //     self->rx_pin  = rx->number;
-    //     claim_pin(rx);
-    // } else {
-    //     self->rx_pin = NO_PIN;
-    // }
-
-    // usart_async_enable(usart_desc_p);
 }
 
 bool common_hal_busio_uart_deinited(busio_uart_obj_t *self) {
-    return 0;//self->rx_pin == NO_PIN && self->tx_pin == NO_PIN;
+    return 0;
 }
 
 void common_hal_busio_uart_deinit(busio_uart_obj_t *self) {
-    // if (common_hal_busio_uart_deinited(self)) {
-    //     return;
-    // }
-    // // This assignment is only here because the usart_async routines take a *const argument.
-    // struct usart_async_descriptor * const usart_desc_p = (struct usart_async_descriptor * const) &self->usart_desc;
-    // usart_async_disable(usart_desc_p);
-    // usart_async_deinit(usart_desc_p);
-    // reset_pin_number(self->rx_pin);
-    // reset_pin_number(self->tx_pin);
-    // self->rx_pin = NO_PIN;
-    // self->tx_pin = NO_PIN;
 }
 
 // Read characters.
 size_t common_hal_busio_uart_read(busio_uart_obj_t *self, uint8_t *data, size_t len, int *errcode) {
-//     if (self->rx_pin == NO_PIN) {
-//         mp_raise_ValueError(translate("No RX pin"));
-//     }
-
-//     // This assignment is only here because the usart_async routines take a *const argument.
-//     struct usart_async_descriptor * const usart_desc_p = (struct usart_async_descriptor * const) &self->usart_desc;
-
-//     if (len == 0) {
-//         // Nothing to read.
-//         return 0;
-//     }
-
-//     struct io_descriptor *io;
-//     usart_async_get_io_descriptor(usart_desc_p, &io);
-
-//     size_t total_read = 0;
-//     uint64_t start_ticks = ticks_ms;
-
-//     // Busy-wait until timeout or until we've read enough chars.
-//     while (ticks_ms - start_ticks <= self->timeout_ms) {
-//         // Read as many chars as we can right now, up to len.
-//         size_t num_read = io_read(io, data, len);
-
-//         // Advance pointer in data buffer, and decrease how many chars left to read.
-//         data += num_read;
-//         len -= num_read;
-//         total_read += num_read;
-//         if (len == 0) {
-//             // Don't need to read any more: data buf is full.
-//             break;
-//         }
-//         if (num_read > 0) {
-//             // Reset the timeout on every character read.
-//             start_ticks = ticks_ms;
-//         }
-// #ifdef MICROPY_VM_HOOK_LOOP
-//         MICROPY_VM_HOOK_LOOP ;
-//         // Allow user to break out of a timeout with a KeyboardInterrupt.
-//         if (mp_hal_is_interrupted()) {
-//             break;
-//         }
-// #endif
-//         // If we are zero timeout, make sure we don't loop again (in the event
-//         // we read in under 1ms)
-//         if (self->timeout_ms == 0) {
-//             break;
-//         }
-//     }
-
-//     if (total_read == 0) {
-//         *errcode = EAGAIN;
-//         return MP_STREAM_ERROR;
-//     }
-
-    return 0;//total_read;
+    return 0;
 }
 
 // Write characters.
 size_t common_hal_busio_uart_write(busio_uart_obj_t *self, const uint8_t *data, size_t len, int *errcode) {
-    // if (self->tx_pin == NO_PIN) {
-    //     mp_raise_ValueError(translate("No TX pin"));
-    // }
-
-    // // This assignment is only here because the usart_async routines take a *const argument.
-    // struct usart_async_descriptor * const usart_desc_p = (struct usart_async_descriptor * const) &self->usart_desc;
-
-    // struct io_descriptor *io;
-    // usart_async_get_io_descriptor(usart_desc_p, &io);
-
-    // if (io_write(io, data, len) < 0) {
-    //     *errcode = MP_EAGAIN;
-    //     return MP_STREAM_ERROR;
-    // }
-
-    // // Wait until write is complete or timeout.
-    // bool done = false;
-    // uint64_t start_ticks = ticks_ms;
-    // // Busy-wait for timeout.
-    // while (ticks_ms - start_ticks < self->timeout_ms) {
-    //     if (usart_async_is_tx_empty(usart_desc_p)) {
-    //         done = true;
-    //         break;
-    //     }
-    //     #ifdef MICROPY_VM_HOOK_LOOP
-    //         MICROPY_VM_HOOK_LOOP
-    //     #endif
-    // }
-
-    // if (!done) {
-    //     *errcode = MP_EAGAIN;
-    //     return MP_STREAM_ERROR;
-    // }
-
-    // // All the characters got written.
-    return 0;//len;
+    return 0;
 }
 
 uint32_t common_hal_busio_uart_get_baudrate(busio_uart_obj_t *self) {
-    return 0;//self->baudrate;
+    return 0;
 }
 
 void common_hal_busio_uart_set_baudrate(busio_uart_obj_t *self, uint32_t baudrate) {
-    // This assignment is only here because the usart_async routines take a *const argument.
-    // struct usart_async_descriptor * const usart_desc_p = (struct usart_async_descriptor * const) &self->usart_desc;
-    // usart_async_set_baud_rate(usart_desc_p,
-    //                           // Samples and ARITHMETIC vs FRACTIONAL must correspond to USART_SAMPR in
-    //                           // hpl_sercom_config.h.
-    //                           _usart_async_calculate_baud_rate(baudrate,  // e.g. 9600 baud
-    //                                                            PROTOTYPE_SERCOM_USART_ASYNC_CLOCK_FREQUENCY,
-    //                                                            16,   // samples
-    //                                                            USART_BAUDRATE_ASYNCH_ARITHMETIC,
-    //                                                            0  // fraction - not used for ARITHMETIC
-    //                                                            ));
-    // self->baudrate = baudrate;
 }
 
 uint32_t common_hal_busio_uart_rx_characters_available(busio_uart_obj_t *self) {
-    // // This assignment is only here because the usart_async routines take a *const argument.
-    // struct usart_async_descriptor * const usart_desc_p = (struct usart_async_descriptor * const) &self->usart_desc;
-    // struct usart_async_status async_status;
-    // usart_async_get_status(usart_desc_p, &async_status);
-    return 0;//async_status.rxcnt;
+    return 0;
 }
 
 void common_hal_busio_uart_clear_rx_buffer(busio_uart_obj_t *self) {
-    // This assignment is only here because the usart_async routines take a *const argument.
-    // struct usart_async_descriptor * const usart_desc_p = (struct usart_async_descriptor * const) &self->usart_desc;
-    // usart_async_flush_rx_buffer(usart_desc_p);
-
 }
 
 bool common_hal_busio_uart_ready_to_tx(busio_uart_obj_t *self) {
-    // if (self->tx_pin == NO_PIN) {
-    //     return false;
-    // }
-    // // This assignment is only here because the usart_async routines take a *const argument.
-    // const struct _usart_async_device * const usart_device_p =
-    //     (struct _usart_async_device * const) &self->usart_desc.device;
-    return 0;//_usart_async_is_byte_sent(usart_device_p);
+    return 0;
 }