fw/common/ - copied from IDBG and generalized a little

2025-04-21 12:27:27 +03:00 · 2010-08-13 08:47:13 -03:00
parent c55fc4018d
commit bdfe058079
8 changed files with 1163 additions and 0 deletions
--- a/fw/common/uart.c
+++ b/fw/common/uart.c
@@ -0,0 +1,125 @@
+/*
+ * common/uart.c - UART initialization and debug output
+ *
+ * Written 2008, 2009 by Werner Almesberger
+ * Copyright 2008, 2009 Werner Almesberger
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+
+#include <stdarg.h>
+#include <stdio.h>
+
+#include "regs.h"
+#include "uart.h"
+
+
+/* gpio j4=0 */
+
+
+#ifndef CONFIG_USB_PUTCHAR
+
+void putchar(char c)
+{
+	if (c == '\n')
+		putchar('\r');
+	SBUF0 = c;
+	while (!TI0);
+	TI0 = 0;
+}
+
+#endif /* !CONFIG_USB_PUTCHAR */
+
+
+/* for now, we always use printf_tiny, which doesn't have a vprintf* version */
+#ifdef noCONFIG_PRINTK
+
+void printk(const char *fmt, ...)
+{
+	va_list ap;
+	__bit saved;
+
+	va_start(ap, fmt);
+	saved = EA;
+	EA = 0;
+	vprintf(fmt, ap);
+	EA = saved;
+	va_end(ap);
+}
+
+#endif /* CONFIG_PRINTK */
+
+
+void uart_init(uint8_t brg_mhz)
+{
+	/*
+	 * UART: Enable only transmitter, no interrupts.
+	 */
+	SCON0 = 0; /* also clears TI0 */
+	SMOD0 = S0DL1 | S0DL0;
+
+	/*
+	 * Configure the UART to 115200bps, see table 13.1
+	 *
+	 * We can's support 1.5MHz (that is, without using the USB clock, but
+	 * why would one want to run the core at 1.5MHz when USB is around ?)
+	 *
+	 * The closes settings would be:
+	 *
+	 * SBRL0 = 0xfff9; -- 107142.9 bps, error = -7%
+	 * SBRL0 = 0xfffa; --  125000 bps, error = +8.5%
+	 *
+	 * Depending on signal quality, we would need something like +/-5%.
+	 */
+
+#if defined(UART_115200_BPS)
+	switch (brg_mhz) {
+	case 3:
+		SBRL0 = 0xfff3;
+		break;
+	case 6:
+		SBRL0 = 0xffe6;
+		break;
+	case 12:
+		SBRL0 = 0xffcc;
+		break;
+	case 24:
+		SBRL0 = 0xff98;
+		break;
+	case 48:
+		SBRL0 = 0xff30;
+		break;
+	}
+#elif defined(UART_57600_BPS)
+	switch (brg_mhz) {
+	case 3:
+		SBRL0 = 0xffe6;
+		break;
+	case 6:
+		SBRL0 = 0xffcc;
+		break;
+	case 12:
+		SBRL0 = 0xff98;
+		break;
+	case 24:
+		SBRL0 = 0xff30;
+		break;
+	case 48:
+		SBRL0 = 0xfe5f;
+		break;
+	}
+#else
+#error "must set either UART_115200_BPS or UART_57600_BPS"
+#endif
+
+	SBCON0 = SB0RUN | SB0PS0 | SB0PS1;
+
+	/*
+	 * Make TX a push-pull output
+	 */
+	P0MDOUT |= 1 << 4;
+}