X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=firmware%2Fs88w-r.c;fp=firmware%2Fs88w-r.c;h=dac0cfcaf85948eeebd70f2eaebae030d9fe3ac6;hb=af6a469f761ceec44e94bea5fe8e5345fd368966;hp=0000000000000000000000000000000000000000;hpb=fd3352aba49e455947bdcbfccc8a37e165564ba3;p=model-railway-devices.git

diff --git a/firmware/s88w-r.c b/firmware/s88w-r.c
new file mode 100644
index 0000000..dac0cfc
--- /dev/null
+++ b/firmware/s88w-r.c
@@ -0,0 +1,120 @@
+/* $Id$
+
+This file is part of the MSP Märklin suite
+Copyright © 2010  Mikkosoft Productions, Mikko Rasa
+Distributed under the GPL
+
+Firmware for wireless S88 receiver module
+
+S88 pinout:
+1 - DATA
+2 - GND
+3 - CLOCK
+4 - LOAD
+5 - RESET
+6 - POWER
+
+ATMega pinout:
+D0 - serial RX
+D1 - serial TX
+D2 - S88 DATA
+D3 - S88 CLOCK
+D4 - S88 LOAD
+D5 - S88 RESET
+*/
+
+#include <avr/io.h>
+#include <avr/interrupt.h>
+
+#define DATA_OUT PORTD2
+#define CLOCK    PIND3
+#define LOAD     PIND4
+#define RESET    PIND5
+
+#define BIT(n)   (1<<(n))
+
+uint8_t decode_hex(uint8_t);
+
+volatile uint8_t rx_buf[3];
+volatile uint8_t rx_fill = 0;
+volatile uint8_t input = 0;
+volatile uint8_t latch = 0;
+
+int main()
+{
+	uint8_t clock_high = 0;
+	uint8_t bits = 0;
+
+	DDRD = 0x06;  // 00000110
+	PIND = 0xC0;  // 11000000
+	DDRB = 0x20;  // 00100000
+	PINB = 0x1F;  // 00011111
+
+	// 9600 baud, 8N1
+	UBRR0H = 0;
+	UBRR0L = 103;
+	UCSR0C = BIT(UCSZ00) | BIT(UCSZ01);
+	UCSR0B = BIT(RXEN0) | BIT(TXEN0) | BIT(RXCIE0);
+
+	sei();
+
+	while(1)
+	{
+		uint8_t d_pins;
+
+		d_pins = PIND;
+
+		if(d_pins&BIT(CLOCK))
+		{
+			if(!clock_high)
+			{
+				if(d_pins&BIT(LOAD))
+					bits = latch;
+				else
+					bits >>= 1;
+
+				if(bits&1)
+					PORTD |= BIT(DATA_OUT);
+				else
+					PORTD &= ~BIT(DATA_OUT);
+
+				clock_high = 1;
+			}
+		}
+		else if(clock_high)
+			clock_high = 0;
+
+		if(d_pins&BIT(RESET))
+			latch = input;
+	}
+}
+
+ISR(USART_RX_vect)
+{
+	uint8_t c = UDR0;
+	if(rx_fill==0)
+	{
+		if(c==':')
+			rx_buf[rx_fill++] = c;
+	}
+	else
+	{
+		rx_buf[rx_fill++] = c;
+		if(rx_buf[0]==':' && rx_fill==3)
+		{
+			input = (decode_hex(rx_buf[1])<<4) | decode_hex(rx_buf[2]);
+			latch |= input;
+			rx_fill = 0;
+		}
+	}
+}
+
+uint8_t decode_hex(uint8_t c)
+{
+	if(c>='0' && c<='9')
+		return c-'0';
+	else if(c>='A' && c<='F')
+		return 0xA+(c-'A');
+	else
+		return 0;
+}