Maxim MAX1110/1111 ADC chip.

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@2755 c046a42c-6fe2-441c-8c8c-71466251a162

hw/max111x.c

+/*
+ * Maxim MAX1110/1111 ADC chip emulation.
+ *
+ * Copyright (c) 2006 Openedhand Ltd.
+ * Written by Andrzej Zaborowski <balrog@zabor.org>
+ *
+ * This code is licensed under the GNU GPLv2.
+ */
+
+#include <vl.h>
+
+struct max111x_s {
+    qemu_irq interrupt;
+    uint8_t tb1, rb2, rb3;
+    int cycle;
+
+    int input[8];
+    int inputs, com;
+};
+
+/* Control-byte bitfields */
+#define CB_PD0		(1 << 0)
+#define CB_PD1		(1 << 1)
+#define CB_SGL		(1 << 2)
+#define CB_UNI		(1 << 3)
+#define CB_SEL0		(1 << 4)
+#define CB_SEL1		(1 << 5)
+#define CB_SEL2		(1 << 6)
+#define CB_START	(1 << 7)
+
+#define CHANNEL_NUM(v, b0, b1, b2)	\
+			((((v) >> (2 + (b0))) & 4) |	\
+			 (((v) >> (3 + (b1))) & 2) |	\
+			 (((v) >> (4 + (b2))) & 1))
+
+uint32_t max111x_read(void *opaque)
+{
+    struct max111x_s *s = (struct max111x_s *) opaque;
+
+    if (!s->tb1)
+        return 0;
+
+    switch (s->cycle ++) {
+    case 1:
+        return s->rb2;
+    case 2:
+        return s->rb3;
+    }
+
+    return 0;
+}
+
+/* Interpret a control-byte */
+void max111x_write(void *opaque, uint32_t value)
+{
+    struct max111x_s *s = (struct max111x_s *) opaque;
+    int measure, chan;
+
+    /* Ignore the value if START bit is zero */
+    if (!(value & CB_START))
+        return;
+
+    s->cycle = 0;
+
+    if (!(value & CB_PD1)) {
+        s->tb1 = 0;
+        return;
+    }
+
+    s->tb1 = value;
+
+    if (s->inputs == 8)
+        chan = CHANNEL_NUM(value, 1, 0, 2);
+    else
+        chan = CHANNEL_NUM(value & ~CB_SEL0, 0, 1, 2);
+
+    if (value & CB_SGL)
+        measure = s->input[chan] - s->com;
+    else
+        measure = s->input[chan] - s->input[chan ^ 1];
+
+    if (!(value & CB_UNI))
+        measure ^= 0x80;
+
+    s->rb2 = (measure >> 2) & 0x3f;
+    s->rb3 = (measure << 6) & 0xc0;
+
+    if (s->interrupt)
+        qemu_irq_raise(s->interrupt);
+}
+
+static struct max111x_s *max111x_init(qemu_irq cb)
+{
+    struct max111x_s *s;
+    s = (struct max111x_s *)
+            qemu_mallocz(sizeof(struct max111x_s));
+    memset(s, 0, sizeof(struct max111x_s));
+
+    s->interrupt = cb;
+
+    /* TODO: add a user interface for setting these */
+    s->input[0] = 0xf0;
+    s->input[1] = 0xe0;
+    s->input[2] = 0xd0;
+    s->input[3] = 0xc0;
+    s->input[4] = 0xb0;
+    s->input[5] = 0xa0;
+    s->input[6] = 0x90;
+    s->input[7] = 0x80;
+    s->com = 0;
+    return s;
+}
+
+struct max111x_s *max1110_init(qemu_irq cb)
+{
+    struct max111x_s *s = max111x_init(cb);
+    s->inputs = 8;
+    return s;
+}
+
+struct max111x_s *max1111_init(qemu_irq cb)
+{
+    struct max111x_s *s = max111x_init(cb);
+    s->inputs = 4;
+    return s;
+}
+
+void max111x_set_input(struct max111x_s *s, int line, uint8_t value)
+{
+    if (line >= s->inputs) {
+        printf("%s: There's no input %i\n", __FUNCTION__, line);
+        return;
+    }
+
+    s->input[line] = value;
+}

vl.h

@@ -1506,6 +1506,14 @@ uint32_t ads7846_read(void *opaque);
 void ads7846_write(void *opaque, uint32_t value);
 struct ads7846_state_s *ads7846_init(qemu_irq penirq);
 
+/* max111x.c */
+struct max111x_s;
+uint32_t max111x_read(void *opaque);
+void max111x_write(void *opaque, uint32_t value);
+struct max111x_s *max1110_init(qemu_irq cb);
+struct max111x_s *max1111_init(qemu_irq cb);
+void max111x_set_input(struct max111x_s *s, int line, uint8_t value);
+
 /* PCMCIA/Cardbus */
 
 struct pcmcia_socket_s {