From 9d87c925a9eaa4fc256be3173c14a20d1469472d Mon Sep 17 00:00:00 2001
From: fishsoupisgood <github@madingley.org>
Date: Wed, 9 Sep 2020 11:53:37 +0100
Subject: everything, mostly, working

---
 boiler-monster/stm32/app/ot_phy_rx.c | 177 +++++++++++++++++++++++++++++++++++
 1 file changed, 177 insertions(+)
 create mode 100644 boiler-monster/stm32/app/ot_phy_rx.c

(limited to 'boiler-monster/stm32/app/ot_phy_rx.c')

diff --git a/boiler-monster/stm32/app/ot_phy_rx.c b/boiler-monster/stm32/app/ot_phy_rx.c
new file mode 100644
index 0000000..9348d24
--- /dev/null
+++ b/boiler-monster/stm32/app/ot_phy_rx.c
@@ -0,0 +1,177 @@
+#include "project.h"
+
+#define OT_THM_IN       GPIO6
+#define OT_THM_IN_PORT    GPIOB
+
+#define OT_BLR_IN       GPIO7
+#define OT_BLR_IN_PORT    GPIOB
+
+
+#define OT_RX_IRQ     NVIC_EXTI9_5_IRQ
+
+
+typedef struct rx_phy  {
+  uint32_t last_cycle;
+  int last_v;
+  unsigned half_bits;
+  unsigned data_bits;
+  int frame_error;
+  uint8_t data[10];
+  int parity;
+} RX_Phy;
+
+
+static RX_Phy p_thm, p_blr;
+
+
+static uint32_t
+cycle_diff (uint32_t a, uint32_t b)
+{
+  return b - a;
+}
+
+
+
+
+static void ot_phy_rx_bit (RX_Phy *p)
+{
+
+
+  if (p->half_bits & 1)
+    p->frame_error = 1;
+
+  if (!p->half_bits) {
+    if (!p->last_v)
+      p->frame_error = 1;
+
+    return;
+  }
+
+  if (p->data_bits < 32) {
+    if (p->last_v) p->data[p->data_bits >> 3] |= 0x80 >> (p->data_bits & 7);
+
+    p->parity ^= p->last_v;
+  } else if (p->data_bits == 32) {
+    if ((!p->last_v) || (p->parity))
+      p->frame_error = 1;
+
+    led_blink();
+
+    if (p == &p_thm)
+      ot_rx_thm (p->data, p->frame_error);
+    else
+      ot_rx_blr (p->data, p->frame_error);
+  }
+
+
+  p->data_bits++;
+
+}
+
+
+static void ot_phy_rx_worker (RX_Phy *p, int v)
+{
+  uint32_t now, diff;
+
+  if (v == p->last_v) return;
+
+
+  now = dwt_read_cycle_counter();
+  diff = cycle_diff (p->last_cycle, now);
+
+
+  if (diff < 10000) return;
+
+  if (diff < 50000) {
+    if (! (p->half_bits & 1)) ot_phy_rx_bit (p);
+
+    p->half_bits++;
+  } else if (diff < 85000) {
+    p->half_bits++;
+    ot_phy_rx_bit (p);
+    p->half_bits++;
+  } else {
+    p->parity = 0;
+    p->half_bits = 0;
+    p->frame_error = 0;
+    p->data_bits = 0;
+    memset (p->data, 0, sizeof (p->data));
+  }
+
+  p->last_cycle = now;
+  p->last_v = v;
+}
+
+
+
+void
+exti9_5_isr (void)
+{
+  int v;
+
+  if (EXTI_PR & OT_THM_IN) {
+    EXTI_PR = OT_THM_IN;
+    v = !GET (OT_THM_IN);
+
+#if 0
+
+    if (v)
+      CLEAR (OT_BLR_OUT);
+    else
+      SET (OT_BLR_OUT);
+
+#endif
+
+    ot_phy_rx_worker (&p_thm, v);
+
+
+  }
+
+  if (EXTI_PR & OT_BLR_IN) {
+    EXTI_PR = OT_BLR_IN;
+    v = !GET (OT_BLR_IN);
+
+#if 0
+
+    if (v)
+      CLEAR (OT_THM_OUT);
+    else
+      SET (OT_THM_OUT);
+
+#endif
+
+    ot_phy_rx_worker (&p_blr, v);
+  }
+
+  return;
+}
+
+
+void ot_phy_rx_tick (void)
+{
+}
+
+
+
+void ot_phy_rx_init (void)
+{
+  MAP_INPUT_PU (OT_THM_IN);
+  MAP_INPUT_PU (OT_BLR_IN);
+
+
+  exti_select_source (OT_THM_IN, OT_THM_IN_PORT);
+  exti_set_trigger (OT_THM_IN, EXTI_TRIGGER_BOTH);
+  exti_enable_request (OT_THM_IN);
+  exti_reset_request (OT_THM_IN);
+
+  exti_select_source (OT_BLR_IN, OT_BLR_IN_PORT);
+  exti_set_trigger (OT_BLR_IN, EXTI_TRIGGER_BOTH);
+  exti_enable_request (OT_BLR_IN);
+  exti_reset_request (OT_BLR_IN);
+
+  nvic_enable_irq (OT_RX_IRQ);
+
+}
+
+
+
-- 
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