Get tc_cdiv working (presumably, need to check on the oscilloscope)

Add adc code to read the field strength


git-svn-id: https://svn.openpcd.org:2342/trunk@325 6dc7ffe9-61d6-0310-9af1-9938baff3ed1

1 files changed, 45 insertions, 0 deletions

diff --git a/openpicc/application/adc.c b/openpicc/application/adc.c
new file mode 100644
index 0000000..4aa900e
--- /dev/null
+++ b/openpicc/application/adc.c
@@ -0,0 +1,45 @@
+/* AT91 ADC for OpenPICC
+ * (C) 2007 Henryk Plötz <henryk@ploetzli.ch> 
+ *
+ *  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.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+
+#include "openpicc.h"
+#include "board.h"
+
+#include <sys/types.h>
+#include <lib_AT91SAM7.h>
+
+static AT91S_ADC* adc = AT91C_BASE_ADC;
+
+int adc_get_field_strength(void)
+{
+	adc->ADC_CR = AT91C_ADC_START;
+	while( (adc->ADC_SR & AT91C_ADC_EOC4)==0) ;
+	return adc->ADC_CDR4;
+}
+
+void adc_init(void)
+{
+	// PRESCAL = 4 -> ADC clock = MCLK / 10 = 4.8 MHz (max is 5 MHz at 10 bit)
+	// Start time <20 us -> STARTUP=11
+	// Track and hold time >600 ns -> SHTIM=2
+	adc->ADC_MR = AT91C_ADC_TRGEN_DIS | AT91C_ADC_LOWRES_10_BIT | 
+		AT91C_ADC_SLEEP_MODE | (4 << 8) | (11 << 16) | (2 << 24);
+	adc->ADC_IDR = 0xfffff;
+	adc->ADC_CHER = OPENPICC_ADC_FIELD_STRENGTH;
+}