Diff: vcom.cpp

Revision:

0:fa7450a43b99

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/vcom.cpp	Mon Dec 04 09:32:20 2017 +0000
@@ -0,0 +1,62 @@
+/*
+  Plastic Logic EPD project on MSP430
+
+  Copyright (C) 2013 Plastic Logic Limited
+
+  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 3 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, see <http://www.gnu.org/licenses/>.
+*/
+/*
+ * vcom.c -- VCOM Calculation support
+ *
+ * Authors: Nick Terry <nick.terry@plasticlogic.com>
+ *
+ */
+
+#include "assert.h"
+#include "vcom.h"
+#include <stdlib.h>
+
+#define LOG_TAG "vcom"
+#include "utils.h"
+
+void vcom_init(struct vcom_cal *v, const struct pl_hw_vcom_info *c)
+{
+	assert(v != NULL);
+	assert(c != NULL);
+
+	v->dac_dx = c->dac_x2 - c->dac_x1;
+	v->dac_dy = c->dac_y2 - c->dac_y1;
+	v->dac_offset = c->dac_y1 -
+		DIV_ROUND_CLOSEST((c->dac_x1 * v->dac_dy),  v->dac_dx);
+	v->swing = c->vgpos_mv - c->vgneg_mv;
+	v->swing_ideal = c->swing_ideal;
+	v->dac_step_mv = DIV_ROUND_CLOSEST(v->dac_dy, v->dac_dx);
+}
+
+int vcom_calculate(const struct vcom_cal *v, int input_mv)
+{
+	int32_t scaled_mv;
+	int dac_value;
+
+	assert(v != NULL);
+
+	scaled_mv = DIV_ROUND_CLOSEST(input_mv * v->swing, v->swing_ideal);
+	dac_value = DIV_ROUND_CLOSEST((scaled_mv - v->dac_offset) * v->dac_dx,
+				      v->dac_dy);
+
+	LOG("input: %d, scaled: %ld, DAC reg: 0x%02X",
+	    input_mv, scaled_mv, dac_value);
+
+	return dac_value;
+}