add DMX driver for MSP430FR5969 and MSP430FR5994 launchpads

1 files changed, 66 insertions, 0 deletions

diff --git a/src/arch/msp430fr5969lp/driver/dmx.cc b/src/arch/msp430fr5969lp/driver/dmx.cc
new file mode 100644
index 0000000..162c2c7
--- /dev/null
+++ b/src/arch/msp430fr5969lp/driver/dmx.cc
@@ -0,0 +1,66 @@
+/*
+ * Copyright 2022 Daniel Friesel
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+#include <msp430.h>
+#include "arch.h"
+#include "driver/dmx.h"
+#include "driver/gpio.h"
+
+/*
+ * Baud rate calculation according to datasheet:
+ * N := f_{BRCLK} / Baudrate = F_CPU / 115200 in our case
+ * if N <= 16: OS16 = 0, UCBR0 = int(N)
+ * if N > 16: OS16 = 1, UCBR0 = int(N/16), UCBRF0 = int(((n/16) - int(n/16)) * 16) = int(N)%16
+ * Set UCBRS0 according to table 21-4
+ */
+
+void DMX::setup()
+{
+	UCA1CTLW0 |= UCSWRST;
+#if F_CPU == 16000000UL
+	// 16M / 250000 == 64 -> UCOS16 = 1, UCBR0 = 4, UCBRF0 = 0, UCBRS0 = 0x00
+	UCA1CTLW0 = UCSWRST | UCSPB | UCSSEL__SMCLK; // MSB first, 8 data bits, 2 stop bits
+	UCA1MCTLW = UCOS16;
+	UCA1BR0 = 4;
+#else
+#error Unsupported F_CPU
+#endif
+
+	UCA1IRCTL = 0;
+	UCA1ABCTL = 0;
+
+	P2SEL0 &= ~BIT5;
+	P2SEL1 |= BIT5;
+	P2DIR |= BIT5;
+
+	UCA1CTLW0 &= ~UCSWRST;
+}
+
+void DMX::write()
+{
+	// Disable UART for reset and mark signals
+	UCA1CTLW0 |= UCSWRST;
+	P2SEL1 &= ~BIT5;
+	gpio.output(GPIO::p2_5, 0);
+	arch.delay_us(88); // break / reset
+	gpio.output(GPIO::p2_5, 1);
+	arch.delay_us(8); // mark
+	P2SEL1 |= BIT5;
+	UCA1CTLW0 &= ~UCSWRST; // causes line to go high
+	for (unsigned char i = 0; i < 16; i++) {
+		while (!(UCA1IFG & UCTXIFG));
+		UCA1TXBUF = frames[i];
+	}
+	for (unsigned char i = 0; i < 241; i++) {
+		while (!(UCA1IFG & UCTXIFG));
+		UCA1TXBUF = 0;
+	}
+	for (unsigned char i = 0; i < 255; i++) {
+		while (!(UCA1IFG & UCTXIFG));
+		UCA1TXBUF = 0;
+	}
+}
+
+DMX dmx;