watch library: implement UART

4 files changed, 149 insertions, 40 deletions

diff --git a/watch-library/hardware/hw/driver_init.h b/watch-library/hardware/hw/driver_init.h
index d1c33218..6b5abaf3 100644
--- a/watch-library/hardware/hw/driver_init.h
+++ b/watch-library/hardware/hw/driver_init.h
@@ -33,6 +33,7 @@ extern "C" {
 #include <hal_ext_irq.h>
 #include <hal_i2c_m_sync.h>
 #include <hal_spi_m_sync.h>
+#include <hal_usart_sync.h>
 #include <hal_delay.h>
 #include <hal_slcd_sync.h>
 
@@ -40,6 +41,8 @@ extern struct adc_sync_descriptor ADC_0;
 
 extern struct i2c_m_sync_desc I2C_0;
 
+extern struct usart_sync_descriptor USART_0;
+
 extern struct slcd_sync_descriptor SEGMENT_LCD_0;
 
 void I2C_0_CLOCK_init(void);
diff --git a/watch-library/hardware/watch/watch_uart.c b/watch-library/hardware/watch/watch_uart.c
index 64b63bee..c8e0600d 100644
--- a/watch-library/hardware/watch/watch_uart.c
+++ b/watch-library/hardware/watch/watch_uart.c
@@ -22,6 +22,103 @@
  * SOFTWARE.
  */
 
+#include "watch_uart.h"
+#include <string.h>
+
+struct usart_sync_descriptor USART_0;
+struct io_descriptor *uart_io;
+
+void watch_enable_uart(const uint8_t tx_pin, const uint8_t rx_pin, uint32_t baud) {
+    SERCOM_USART_CTRLA_Type ctrla;
+    SERCOM_USART_CTRLB_Type ctrlb;
+    ctrla.reg = SERCOM_USART_CTRLA_DORD | SERCOM_USART_CTRLA_MODE(1);
+    ctrlb.reg = SERCOM_USART_CTRLB_CHSIZE(0);
+
+    MCLK->APBCMASK.reg |= MCLK_APBCMASK_SERCOM3;
+    GCLK->PCHCTRL[SERCOM3_GCLK_ID_CORE].reg = GCLK_PCHCTRL_GEN(0) | GCLK_PCHCTRL_CHEN;
+
+    while (0 == (GCLK->PCHCTRL[SERCOM3_GCLK_ID_CORE].reg & GCLK_PCHCTRL_CHEN)) {
+        // wait
+    }
+
+	usart_sync_init(&USART_0, SERCOM3, (void *)NULL);
+
+    SERCOM3->USART.CTRLA.reg &= ~SERCOM_USART_CTRLA_ENABLE;
+
+    switch (tx_pin) {
+        case A2:
+            gpio_set_pin_direction(tx_pin, GPIO_DIRECTION_OUT);
+            gpio_set_pin_function(tx_pin, PINMUX_PB02C_SERCOM3_PAD0);
+            ctrla.reg |= SERCOM_USART_CTRLA_TXPO(0);
+            ctrlb.reg |= SERCOM_USART_CTRLB_TXEN;
+            break;
+        case A4:
+            gpio_set_pin_direction(tx_pin, GPIO_DIRECTION_OUT);
+            gpio_set_pin_function(tx_pin, PINMUX_PB00C_SERCOM3_PAD2);
+            ctrla.reg |= SERCOM_USART_CTRLA_TXPO(1);
+            ctrlb.reg |= SERCOM_USART_CTRLB_TXEN;
+            break;
+        default:
+            break;
+    }
+
+    switch (rx_pin) {
+        case A1:
+            gpio_set_pin_direction(rx_pin, GPIO_DIRECTION_IN);
+            gpio_set_pin_function(rx_pin, PINMUX_PB01C_SERCOM3_PAD3);
+            ctrla.reg |= SERCOM_USART_CTRLA_RXPO(3);
+            ctrlb.reg |= SERCOM_USART_CTRLB_RXEN;
+            break;
+        case A2:
+            gpio_set_pin_direction(rx_pin, GPIO_DIRECTION_IN);
+            gpio_set_pin_function(rx_pin, PINMUX_PB02C_SERCOM3_PAD0);
+            ctrla.reg |= SERCOM_USART_CTRLA_RXPO(0);
+            ctrlb.reg |= SERCOM_USART_CTRLB_RXEN;
+            break;
+        case A3:
+            gpio_set_pin_direction(rx_pin, GPIO_DIRECTION_IN);
+            gpio_set_pin_function(rx_pin, PINMUX_PB03C_SERCOM3_PAD1);
+            ctrla.reg |= SERCOM_USART_CTRLA_RXPO(1);
+            ctrlb.reg |= SERCOM_USART_CTRLB_RXEN;
+            break;
+        case A4:
+            gpio_set_pin_direction(rx_pin, GPIO_DIRECTION_IN);
+            gpio_set_pin_function(rx_pin, PINMUX_PB00C_SERCOM3_PAD2);
+            ctrla.reg |= SERCOM_USART_CTRLA_RXPO(2);
+            ctrlb.reg |= SERCOM_USART_CTRLB_RXEN;
+            break;
+        default:
+            break;
+    }
+    SERCOM3->USART.CTRLA.reg = ctrla.reg;
+    SERCOM3->USART.CTRLB.reg = ctrlb.reg;
+
+    if (hri_usbdevice_get_CTRLA_ENABLE_bit(USB)) {
+        uint64_t br = 65536 - ((65536 * 16.0f * baud) / 8000000);
+        SERCOM3->USART.BAUD.reg = (uint16_t)br;
+    } else {
+        uint64_t br = 65536 - ((65536 * 16.0f * baud) / 4000000);
+        SERCOM3->USART.BAUD.reg = (uint16_t)br;
+    }
+
+    SERCOM3->USART.CTRLA.reg |= SERCOM_USART_CTRLA_ENABLE;
+
+	usart_sync_enable(&USART_0);
+    usart_sync_get_io_descriptor(&USART_0, &uart_io);
+}
+
+void watch_uart_puts(char *s) {
+	io_write(uart_io, (uint8_t *)s, strlen(s));
+}
+
+char watch_uart_getc(void) {
+    uint8_t retval;
+    io_read(uart_io, &retval, 1);
+    return retval;
+}
+
+// Begin deprecated functions
+
  /*
  * UART methods are Copyright (c) 2014-2017, Alex Taradov <alex@taradov.com>
  * All rights reserved.
@@ -50,7 +147,6 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include "watch_uart.h"
 #include "peripheral_clk_config.h"
 
 void watch_enable_debug_uart(uint32_t baud) {
diff --git a/watch-library/shared/watch/watch_uart.h b/watch-library/shared/watch/watch_uart.h
index 3e98bd35..04a53e4e 100644
--- a/watch-library/shared/watch/watch_uart.h
+++ b/watch-library/shared/watch/watch_uart.h
@@ -27,32 +27,49 @@
 
 #include "watch.h"
 
-/** @addtogroup debug Debug UART
-  * @brief This section covers functions related to the debug UART, available on
-  *        pin D1 of the 9-pin connector.
-  * @warning These functions were used early on in development, before the TinyUSB
-  *          CDC was implemented. You can now print debug messages to the USB console
-  *          using printf, rendering this bit irrelevant. These methods will likely
-  *          be refactored out in the future, in favor of a more full-featured UART
-  *          on the nine-pin connector.
+/** @addtogroup debug UART
+  * @brief This section covers functions related to the UART peripheral.
   **/
 /// @{
+
+/** @brief Initializes the debug UART.
+  * @param tx_pin The pin the watch will use to transmit, or 0 for a receive-only UART.
+  *               If specified, must be either A2 or A4.
+  * @param rx_pin The pin the watch will use to receive, or 0 for a transmit-only UART.
+  *               If specified, must be A1, A2, A3 or A4 (pin A0 cannot receive UART data).
+  * @param baud The baud rate for the UART. A typical value is 19200.
+  */
+void watch_enable_uart(const uint8_t tx_pin, const uint8_t rx_pin, uint32_t baud);
+
+/** @brief Transmits a string of bytes on the UART's TX pin.
+  * @param s A null-terminated string containing the bytes you wish to transmit.
+  */
+void watch_uart_puts(char *s);
+
+/** @brief Receives a single byte from the UART's RX pin.
+  * @return the received byte.
+  * @note This method will block until a byte is received!
+  */
+char watch_uart_getc(void);
+
+// Begin deprecated functions:
+
 /** @brief Initializes the debug UART.
   * @param baud The baud rate
   */
-__attribute__((deprecated("Use printf to log debug messages over USB.")))
+__attribute__((deprecated("Use watch_enable_uart to enable the UART.")))
 void watch_enable_debug_uart(uint32_t baud);
 
 /** @brief Outputs a single character on the debug UART.
   * @param c The character you wish to output.
   */
-__attribute__((deprecated("Use printf to log debug messages over USB.")))
+__attribute__((deprecated("Use watch_uart_puts to print to the UART, or printf to log debug messages over USB.")))
 void watch_debug_putc(char c);
 
 /** @brief Outputs a string on the debug UART.
   * @param s A null-terminated string.
   */
-__attribute__((deprecated("Use printf to log debug messages over USB.")))
+__attribute__((deprecated("Use watch_uart_puts to print to the UART, or printf to log debug messages over USB.")))
 void watch_debug_puts(char *s);
 /// @}
 #endif
diff --git a/watch-library/simulator/watch/watch_uart.c b/watch-library/simulator/watch/watch_uart.c
index e37fabff..7043383c 100644
--- a/watch-library/simulator/watch/watch_uart.c
+++ b/watch-library/simulator/watch/watch_uart.c
@@ -22,37 +22,30 @@
  * SOFTWARE.
  */
 
- /*
- * UART methods are Copyright (c) 2014-2017, Alex Taradov <alex@taradov.com>
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are met:
- *
- * 1. Redistributions of source code must retain the above copyright notice,
- *    this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- * 3. The name of the author may not be used to endorse or promote products
- *    derived from this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
- * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
- * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
- * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
- * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
- * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
- * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
- * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
- * POSSIBILITY OF SUCH DAMAGE.
- */
-
 #include "watch_uart.h"
 #include "peripheral_clk_config.h"
 
+static bool tx_enable = false;
+static bool rx_enable = false;
+
+void watch_enable_uart(const uint8_t tx_pin, const uint8_t rx_pin, uint32_t baud) {
+    tx_enable = !!tx_pin;
+    rx_enable = !!rx_pin;
+}
+
+void watch_uart_puts(char *s) {
+	if (tx_enable) {
+        // TODO: hook up to UI
+    }
+}
+
+char watch_uart_getc(void) {
+	if (rx_enable) {
+        // TODO: hook up to UI
+    }
+    return 0;
+}
+
 void watch_enable_debug_uart(uint32_t baud) {}
 
 void watch_debug_putc(char c) {}