move software I2C implementation to ATTiny

7 files changed, 187 insertions, 38 deletions

diff --git a/commandline/i2c-util.c b/commandline/i2c-util.c
index 03b2fad..3608e36 100644
--- a/commandline/i2c-util.c
+++ b/commandline/i2c-util.c
@@ -308,6 +308,24 @@ unsigned char i2c_tx_byte(unsigned char byte)
 	return ack;
 }
 
+unsigned char i2c_hw_tx_byte(unsigned char byte)
+{
+	unsigned char buffer[8];
+
+	int nBytes = usb_control_msg(handle,
+			USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_ENDPOINT_IN,
+			USBCMD_TX, 0, byte,
+			(char *)buffer, sizeof(buffer), 5000);
+
+	if (nBytes < 1) {
+		fprintf(stderr, "ERR: tx: got %d bytes, expected 1\n",
+				nBytes);
+		exit(1);
+	}
+
+	return buffer[0];
+}
+
 unsigned char i2c_rx_byte(unsigned char send_ack)
 {
 	signed char i;
@@ -330,6 +348,24 @@ unsigned char i2c_rx_byte(unsigned char send_ack)
 	return ret;
 }
 
+unsigned char i2c_hw_rx_byte(unsigned char send_ack)
+{
+	unsigned char buffer[8];
+
+	int nBytes = usb_control_msg(handle,
+			USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_ENDPOINT_IN,
+			USBCMD_RX, 0, send_ack,
+			(char *)buffer, sizeof(buffer), 5000);
+
+	if (nBytes < 1) {
+		fprintf(stderr, "ERR: tx: got %d bytes, expected 1\n",
+				nBytes);
+		exit(1);
+	}
+
+	return buffer[0];
+}
+
 void i2c_start()
 {
 	set_sda(1);
@@ -342,6 +378,17 @@ void i2c_start()
 	verify_scl_low();
 }
 
+void i2c_hw_start()
+{
+	// discarded
+	unsigned char buffer[8];
+
+	usb_control_msg(handle,
+			USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_ENDPOINT_IN,
+			USBCMD_START, 0, 0,
+			(char *)buffer, sizeof(buffer), 5000);
+}
+
 void i2c_stop()
 {
 	set_scl(1);
@@ -352,6 +399,17 @@ void i2c_stop()
 	verify_sda_high();
 }
 
+void i2c_hw_stop()
+{
+	// discarded
+	unsigned char buffer[8];
+
+	usb_control_msg(handle,
+			USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_ENDPOINT_IN,
+			USBCMD_STOP, 0, 0,
+			(char *)buffer, sizeof(buffer), 5000);
+}
+
 void i2c_init()
 {
 	usb_init();
@@ -365,6 +423,18 @@ void i2c_init()
 			USBDEV_VERSION_MAJOR, USBDEV_VERSION_MINOR);
 		exit(1);
 	}
+	i2c_hw_setbits();
+}
+
+void i2c_hw_setbits()
+{
+	// discarded
+	unsigned char buffer[8];
+
+	usb_control_msg(handle,
+			USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_ENDPOINT_IN,
+			USBCMD_SETBITS, 0, ((1 << bit_scl) << 8) | (1 << bit_sda),
+			(char *)buffer, sizeof(buffer), 5000);
 }
 
 void i2c_deinit()
diff --git a/commandline/i2c-util.h b/commandline/i2c-util.h
index 9be466a..0f47b6e 100644
--- a/commandline/i2c-util.h
+++ b/commandline/i2c-util.h
@@ -10,8 +10,15 @@ unsigned char get_status();
 unsigned char i2c_tx_byte(unsigned char byte);
 unsigned char i2c_rx_byte(unsigned char send_ack);
 
+unsigned char i2c_hw_tx_byte(unsigned char byte);
+unsigned char i2c_hw_rx_byte(unsigned char send_ack);
+
 void i2c_getopt(int argc, char **argv);
 void i2c_start();
 void i2c_stop();
 void i2c_init();
 void i2c_deinit();
+
+void i2c_hw_setbits();
+void i2c_hw_start();
+void i2c_hw_stop();
diff --git a/commandline/i2cdetect.c b/commandline/i2cdetect.c
index 88e5d2e..341900f 100644
--- a/commandline/i2cdetect.c
+++ b/commandline/i2cdetect.c
@@ -24,9 +24,9 @@ int main(int argc, char **argv)
 		}
 
 
-		i2c_start();
+		i2c_hw_start();
 
-		if (i2c_tx_byte(i2cid))
+		if (i2c_hw_tx_byte(i2cid))
 			printf(" %02x", id);
 		else
 			fputs(" --", stdout);
@@ -35,7 +35,7 @@ int main(int argc, char **argv)
 
 	fputs("\n", stdout);
 
-	i2c_stop();
+	i2c_hw_stop();
 	i2c_deinit();
 	return 0;
 }
diff --git a/commandline/i2cget.c b/commandline/i2cget.c
index 9ed8bbd..f2bdb15 100644
--- a/commandline/i2cget.c
+++ b/commandline/i2cget.c
@@ -25,11 +25,11 @@ int main(int argc, char **argv)
 	}
 
 	i2c_init();
-	i2c_start();
+	i2c_hw_start();
 
-	if (!i2c_tx_byte((address << 1) | 0)) {
+	if (!i2c_hw_tx_byte((address << 1) | 0)) {
 		fprintf(stderr, "Received NAK from slave 0x%02x, aborting\n", address);
-		i2c_stop();
+		i2c_hw_stop();
 		i2c_deinit();
 		return 3;
 	}
@@ -38,29 +38,29 @@ int main(int argc, char **argv)
 		cmdbuf = strtol(argv[i], &conv_err, 0);
 		if (conv_err && *conv_err) {
 			fprintf(stderr, "read command: Conversion error at '%s'\n", conv_err);
-			i2c_stop();
+			i2c_hw_stop();
 			i2c_deinit();
 			return 2;
 		}
-		if (!i2c_tx_byte(cmdbuf)) {
+		if (!i2c_hw_tx_byte(cmdbuf)) {
 			fprintf(stderr, "Received NAK after byte %d (0x%02x)\n", i-1, cmdbuf);
-			i2c_stop();
+			i2c_hw_stop();
 			i2c_deinit();
 			return 4;
 		}
 	}
 
-	i2c_start();
-	if (!i2c_tx_byte((address << 1) | 1)) {
+	i2c_hw_start();
+	if (!i2c_hw_tx_byte((address << 1) | 1)) {
 		fprintf(stderr, "Received NAK after reSTART from slave 0x%02x, aborting\n", address);
-		i2c_stop();
+		i2c_hw_stop();
 		i2c_deinit();
 		return 3;
 	}
 
-	ret = i2c_rx_byte(0);
+	ret = i2c_hw_rx_byte(0);
 
-	i2c_stop();
+	i2c_hw_stop();
 	i2c_deinit();
 
 	printf("%i\n", ret);
diff --git a/commandline/i2cset.c b/commandline/i2cset.c
index 2d7567f..bdcd3cc 100644
--- a/commandline/i2cset.c
+++ b/commandline/i2cset.c
@@ -24,11 +24,11 @@ int main(int argc, char **argv)
 	}
 
 	i2c_init();
-	i2c_start();
+	i2c_hw_start();
 
-	if (!i2c_tx_byte(address << 1)) {
+	if (!i2c_hw_tx_byte(address << 1)) {
 		fprintf(stderr, "Received NAK from slave 0x%02x, aborting\n", address);
-		i2c_stop();
+		i2c_hw_stop();
 		i2c_deinit();
 		return 3;
 	}
@@ -37,19 +37,19 @@ int main(int argc, char **argv)
 		cmdbuf = strtol(argv[i], &conv_err, 0);
 		if (conv_err && *conv_err) {
 			fprintf(stderr, "write command: conversion error at '%s'\n", conv_err);
-			i2c_stop();
+			i2c_hw_stop();
 			i2c_deinit();
 			return 2;
 		}
-		if (!i2c_tx_byte(cmdbuf)) {
+		if (!i2c_hw_tx_byte(cmdbuf)) {
 			fprintf(stderr, "Received NAK after byte %d (0x%02x)\n", i-1, cmdbuf);
-			i2c_stop();
+			i2c_hw_stop();
 			i2c_deinit();
 			return 4;
 		}
 	}
 
-	i2c_stop();
+	i2c_hw_stop();
 	i2c_deinit();
 
 	return 0;
diff --git a/firmware/main.c b/firmware/main.c
index 0410134..d04159a 100644
--- a/firmware/main.c
+++ b/firmware/main.c
@@ -33,23 +33,90 @@ Application examples:
 
 USB_PUBLIC uchar usbFunctionSetup(uchar data[8])
 {
-usbRequest_t    *rq = (void *)data;
-static uchar    replyBuf[2];
+	usbRequest_t    *rq = (void *)data;
+	static uchar    replyBuf[2];
+	static uchar    bv_sda, bv_scl, i, buf;
 
-    usbMsgPtr = replyBuf;
-    if(rq->bRequest == USBCMD_ECHO) {  /* ECHO */
-        replyBuf[0] = rq->wValue.bytes[0];
-        replyBuf[1] = rq->wValue.bytes[1];
-        return 2;
-    }
-    if(rq->bRequest == USBCMD_GETPORT) {  /* GET_STATUS -> result = 1 bytes */
-        replyBuf[0] = PINB;
-        return 1;
-    }
-    if(rq->bRequest == USBCMD_SETPORT) { /* SET_STATUS. Payload byte is output. */
-        DDRB = ~(rq->wIndex.bytes[0]);
-    }
-    return 0;
+	usbMsgPtr = replyBuf;
+	if (rq->bRequest == USBCMD_ECHO) {
+		replyBuf[0] = rq->wValue.bytes[0];
+		replyBuf[1] = rq->wValue.bytes[1];
+		return 2;
+	}
+	if (rq->bRequest == USBCMD_GETPORT) {
+		replyBuf[0] = PINB;
+		return 1;
+	}
+	if (rq->bRequest == USBCMD_SETPORT) {
+		DDRB = ~(rq->wIndex.bytes[0]);
+		return 0;
+	}
+	if (rq->bRequest == USBCMD_SETBITS) {
+		bv_sda = rq->wIndex.bytes[0];
+		bv_scl = rq->wIndex.bytes[1];
+		return 0;
+	}
+	if (rq->bRequest == USBCMD_START) {
+		DDRB &= ~(bv_sda | bv_scl);
+		_delay_us(1000);
+		DDRB |= bv_sda;
+		_delay_us(1000);
+		DDRB |= bv_scl;
+		return 0;
+	}
+	if (rq->bRequest == USBCMD_STOP) {
+		DDRB &= ~bv_scl;
+		_delay_us(100);
+		DDRB &= ~bv_sda;
+		_delay_us(100);
+		return 0;
+	}
+	if (rq->bRequest == USBCMD_TX) {
+		buf = rq->wIndex.bytes[0]; // byte to transmit
+		for (i = 0; i <= 8; i++) {
+			if ((buf & 0x80) || (i == 8)) {
+				DDRB &= ~bv_sda;
+			} else {
+				DDRB |= bv_sda;
+			}
+			buf <<= 1;
+			_delay_us(100);
+			DDRB &= ~bv_scl;
+			_delay_us(100);
+			if (i == 8) {
+				if (PINB & bv_sda) {
+					replyBuf[0] = 0;
+				} else {
+					replyBuf[0] = 1;
+				}
+			}
+			DDRB |= bv_scl;
+			_delay_us(100);
+		}
+		return 1;
+	}
+	if (rq->bRequest == USBCMD_RX) {
+		buf = rq->wIndex.bytes[0]; // true <=> transmit ack
+		DDRB &= ~bv_sda;
+		replyBuf[0] = 0;
+		for (i = 0; i <= 8; i++) {
+			if ((i == 8) && buf) {
+				DDRB |= bv_sda;
+			}
+			DDRB &= ~bv_scl;
+			_delay_us(100);
+			if ((i < 8) && ( PINB & bv_sda)) {
+				replyBuf[0] |= _BV(7-i);
+			}
+			else if ((i == 8) && buf) {
+				DDRB &= ~bv_sda;
+			}
+			DDRB |= bv_scl;
+			_delay_us(100);
+		}
+		return 1;
+	}
+	return 0;
 }
 
 /* allow some inter-device compatibility */
diff --git a/global_config.h b/global_config.h
index 1a4e8b5..7fcd122 100644
--- a/global_config.h
+++ b/global_config.h
@@ -1,6 +1,11 @@
 #define USBDEV_VERSION_MAJOR 0
-#define USBDEV_VERSION_MINOR 1
+#define USBDEV_VERSION_MINOR 2
 
 #define USBCMD_ECHO    0
 #define USBCMD_GETPORT 1
 #define USBCMD_SETPORT 2
+#define USBCMD_SETBITS 3
+#define USBCMD_START   4
+#define USBCMD_STOP    5
+#define USBCMD_TX      6
+#define USBCMD_RX      7