1 files changed, 85 insertions, 0 deletions
diff --git a/watch-library/watch/watch_uart.c b/watch-library/watch/watch_uart.c
new file mode 100644
index 00000000..4cbac89b
--- /dev/null
+++ b/watch-library/watch/watch_uart.c
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+/*
+ * MIT License
+ *
+ * Copyright (c) 2020 Joey Castillo
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * 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 "peripheral_clk_config.h"
+
+void watch_enable_debug_uart(uint32_t baud) {
+    uint64_t br = (uint64_t)65536 * (CONF_CPU_FREQUENCY - 16 * baud) / CONF_CPU_FREQUENCY;
+
+    gpio_set_pin_direction(D1, GPIO_DIRECTION_IN);
+    gpio_set_pin_function(D1, PINMUX_PB00C_SERCOM3_PAD2);
+
+    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));
+
+    SERCOM3->USART.CTRLA.reg =
+        SERCOM_USART_CTRLA_DORD | SERCOM_USART_CTRLA_MODE(1/*USART_INT_CLK*/) |
+        SERCOM_USART_CTRLA_RXPO(0/*PAD0*/) | SERCOM_USART_CTRLA_TXPO(1/*PAD2*/);
+
+    SERCOM3->USART.CTRLB.reg = SERCOM_USART_CTRLB_RXEN | SERCOM_USART_CTRLB_TXEN |
+        SERCOM_USART_CTRLB_CHSIZE(0/*8 bits*/);
+
+    SERCOM3->USART.BAUD.reg = (uint16_t)br;
+
+    SERCOM3->USART.CTRLA.reg |= SERCOM_USART_CTRLA_ENABLE;
+}
+
+void watch_debug_putc(char c) {
+    while (!(SERCOM3->USART.INTFLAG.reg & SERCOM_USART_INTFLAG_DRE));
+    SERCOM3->USART.DATA.reg = c;
+}
+
+void watch_debug_puts(char *s) {
+    while (*s) watch_debug_putc(*s++);
+}