From: marco <marco@38d2e660-2303-0410-9eaa-f027e97ec537>
Date: Wed, 20 Sep 2006 20:40:14 +0000 (+0000)
Subject: Added TC520 ADC driver.
X-Git-Tag: 1.0.0~517
X-Git-Url: https://codewiz.org/gitweb?a=commitdiff_plain;h=d4f65018d471c77efa674bf30d5b5938fe6ca3a3;hp=c22f33b299c475e12d1525a82a24f724d0bd68aa;p=bertos.git

Added TC520 ADC driver.


git-svn-id: https://src.develer.com/svnoss/bertos/trunk@724 38d2e660-2303-0410-9eaa-f027e97ec537
---

diff --git a/drv/tc520.c b/drv/tc520.c
new file mode 100755
index 00000000..16df6158
--- /dev/null
+++ b/drv/tc520.c
@@ -0,0 +1,132 @@
+/**
+ * \file
+ * <!--
+ * Copyright 2005 Develer S.r.l. (http://www.develer.com/)
+ * -->
+ *
+ * \version $Id$
+ *
+ * \brief TC520 ADC driver (implementation)
+ *
+ * \version $Id$
+ * \author Francesco Sacchi <batt@develer.com>
+ * \author Marco Benelli <marco@develer.com>
+ */
+
+#include <drv/tc520.h>
+#include <drv/timer.h>
+
+#include <hw_tc520.h>
+
+#include <cfg/macros.h>
+#include <cfg/cpu.h>
+#include <cfg/compiler.h>
+
+#include <drv/ser.h>
+
+static Serial *spi_ser;
+
+#define TC520_CONVERSION_TIMEOUT ms_to_ticks(1000)
+#define INIT_LOAD_VALUE 0x00
+
+/**
+ * Start an AD conversion and return result.
+ * To start a conversion first we must pull down CE pin.
+ * The ADC starts a convertion and keeps the DV pin high until the end.
+ * At this point, we can read the conversion value by SPI.
+ * The convertion result is yield in 3 bytes.
+ * First byte:
+ * bit | Value
+ * ----|-------
+ *  7  | Overrange
+ *  6  | Polarity
+ * 5:0 | data bits 15:10
+ *
+ * Second byte: data 9:2
+ *
+ * Third byte:
+ * bit | Value
+ * ----|-------
+ *  7  | data bit 1
+ *  6  | data bit 0
+ * 5:0 | '0'
+ *
+ * So, to get the result we must shift and recompose the bits.
+ * \Note Ovverrange bit is handled as the 17th data bit.
+ */
+tc520_data_t tc520_read(void)
+{
+	/* Start convertion and wait */
+	CE_LOW();
+	ticks_t start = timer_clock();
+	do
+	{
+		/* timeout check */
+		if (timer_clock() - start >= TC520_CONVERSION_TIMEOUT)
+		{
+			ASSERT(0);
+			CE_HIGH();
+			return TC520_MAX_VALUE;
+		}
+	}
+	while(DV_LOW());
+
+	start = timer_clock();
+	do
+	{
+		/* timeout check */
+		if (timer_clock() - start >= TC520_CONVERSION_TIMEOUT)
+		{
+			ASSERT(0);
+			CE_HIGH();
+			return TC520_MAX_VALUE;
+		}
+	}
+	while(DV_HIGH());
+
+	/* Ok, convertion finished, read result */
+	CE_HIGH();
+	READ_LOW();
+
+	/* RX buffer could be dirty...*/
+	ser_purge(spi_ser);
+
+	/* I/O buffer */
+	uint8_t buf[3] = "\x0\x0\x0";
+
+	/* Dummy write to activate recv */
+	ser_write(spi_ser, buf, sizeof(buf));
+	ser_drain(spi_ser);
+	READ_HIGH();
+
+	/* recv */
+	ASSERT(ser_read(spi_ser, buf, sizeof(buf)) == sizeof(buf));
+
+	tc520_data_t res;
+
+	/* Recompose data */
+	res = (((tc520_data_t)(buf[0] & 0x3F)) << 10) | (((tc520_data_t)buf[1]) << 2) | (((tc520_data_t)buf[2]) >> 6);
+
+	#define OVERRANGE_BIT BV(7)
+	/* Handle overrange bit as 17th bit */
+	if (buf[0] & OVERRANGE_BIT)
+		res |= BV32(16);
+
+	return res;
+}
+
+
+/**
+ * Initialize tc520 A/D converter driver
+ */
+void tc520_init(Serial *spi_port)
+{
+	spi_ser = spi_port;
+	/* init io ports */
+	TC520_HW_INIT;
+	/* Send initial load value */
+	LOAD_LOW();
+	ser_putchar(INIT_LOAD_VALUE, spi_ser);
+	ser_drain(spi_ser);
+	LOAD_HIGH();
+}
diff --git a/drv/tc520.h b/drv/tc520.h
new file mode 100755
index 00000000..c264ad20
--- /dev/null
+++ b/drv/tc520.h
@@ -0,0 +1,30 @@
+/**
+ * \file
+ * <!--
+ * Copyright 2006 Develer S.r.l. (http://www.develer.com/)
+ * -->
+ *
+ * \version $Id$
+ *
+ * \brief TC520 ADC driver (intercace)
+ *
+ * \version $Id$
+ * \author Francesco Sacchi <batt@develer.com>
+ * \author Marco Benelli <marco@develer.com>
+ */
+
+#ifndef DRV_TC520_H
+#define DRV_TC520_H
+
+#include <drv/ser.h>
+#include <cfg/compiler.h>
+
+typedef uint32_t tc520_data_t;
+
+/* 17 bit max value */
+#define TC520_MAX_VALUE 0x1FFFFUL
+
+tc520_data_t tc520_read(void);
+void tc520_init(Serial *spi_port);
+
+#endif  /* DRV_TC520_H */
diff --git a/hw/hw_tc520.h b/hw/hw_tc520.h
new file mode 100755
index 00000000..0fc2320f
--- /dev/null
+++ b/hw/hw_tc520.h
@@ -0,0 +1,51 @@
+/**
+ * \file
+ * <!--
+ * Copyright 2005 Develer S.r.l. (http://www.develer.com/)
+ * -->
+ *
+ * \version $Id$
+ *
+ * \brief TC520 hardware-specific definitions
+ *
+ * \version $Id$
+ * \author Francesco Sacchi <batt@develer.com>
+ */
+
+#ifndef HW_TC520_H
+#define HW_TC520_H
+
+#include <cfg/compiler.h>
+#include <avr/io.h>
+
+#define CE_PIN   PE6
+#define DV_PIN   PE5
+#define LOAD_PIN PE3
+#define READ_PIN PE4
+
+#define TC520_DDR  DDRE
+#define TC520_PORT PORTE
+#define TC520_PIN  PINE
+
+#define DV_HIGH() (TC520_PIN & BV(DV_PIN))
+#define DV_LOW()  (!DV_HIGH())
+
+#define CE_HIGH() (TC520_PORT |= BV(CE_PIN))
+#define CE_LOW()  (TC520_PORT &= ~BV(CE_PIN))
+
+#define LOAD_HIGH() (TC520_PORT |= BV(LOAD_PIN))
+#define LOAD_LOW()  (TC520_PORT &= ~BV(LOAD_PIN))
+
+#define READ_HIGH() (TC520_PORT |= BV(READ_PIN))
+#define READ_LOW()  (TC520_PORT &= ~BV(READ_PIN))
+
+#define TC520_HW_INIT \
+do\
+{\
+	TC520_PORT |= (BV(CE_PIN) | BV(LOAD_PIN) | BV(READ_PIN));\
+	TC520_DDR  |= (BV(CE_PIN) | BV(LOAD_PIN) | BV(READ_PIN));\
+	TC520_DDR  &= ~BV(DV_PIN);\
+}\
+while(0)
+
+#endif /* HW_TC520_H */