Use a dedicated timer

4 files changed, 98 insertions, 27 deletions

diff --git a/shared-module/_pew/PewPew.c b/shared-module/_pew/PewPew.c
index ede8ed9bb..de1224a37 100644
--- a/shared-module/_pew/PewPew.c
+++ b/shared-module/_pew/PewPew.c
@@ -27,14 +27,30 @@
 #include <stdbool.h>
 
 #include "py/mpstate.h"
+#include "py/runtime.h"
 #include "__init__.h"
 #include "PewPew.h"
 
 #include "shared-bindings/digitalio/Pull.h"
 #include "shared-bindings/digitalio/DigitalInOut.h"
 #include "shared-bindings/util.h"
+#include "samd/timers.h"
 
 
+static uint8_t pewpew_tc_index = 0xff;
+
+
+void pewpew_interrupt_handler(uint8_t index) {
+    if (index != pewpew_tc_index) return;
+    Tc* tc = tc_insts[index];
+    if (!tc->COUNT16.INTFLAG.bit.MC0) return;
+
+    pew_tick();
+
+    // Clear the interrupt bit.
+    tc->COUNT16.INTFLAG.reg = TC_INTFLAG_MC0;
+}
+
 void pew_init() {
     pew_obj_t* pew_singleton = MP_STATE_VM(pew_singleton);
     for (size_t i = 0; i < pew_singleton->rows_size; ++i) {
@@ -49,4 +65,57 @@ void pew_init() {
         common_hal_digitalio_digitalinout_switch_to_output(pin, true,
             DRIVE_MODE_OPEN_DRAIN);
     }
+    if (pewpew_tc_index == 0xff) {
+        // Find a spare timer.
+        Tc *tc = NULL;
+        int8_t index = TC_INST_NUM - 1;
+        for (; index >= 0; index--) {
+            if (tc_insts[index]->COUNT16.CTRLA.bit.ENABLE == 0) {
+                tc = tc_insts[index];
+                break;
+            }
+        }
+        if (tc == NULL) {
+            mp_raise_RuntimeError("All timers in use");
+        }
+
+        pewpew_tc_index = index;
+
+        // We use GCLK0 for SAMD21 and GCLK1 for SAMD51 because they both run
+        // at 48mhz making our math the same across the boards.
+        #ifdef SAMD21
+        turn_on_clocks(true, index, 0);
+        #endif
+        #ifdef SAMD51
+        turn_on_clocks(true, index, 1);
+        #endif
+
+
+        #ifdef SAMD21
+        tc->COUNT16.CTRLA.reg = TC_CTRLA_MODE_COUNT16 |
+                                TC_CTRLA_PRESCALER_DIV64 |
+                                TC_CTRLA_WAVEGEN_MFRQ;
+        #endif
+        #ifdef SAMD51
+        tc_reset(tc);
+        tc_set_enable(tc, false);
+        tc->COUNT16.CTRLA.reg = TC_CTRLA_MODE_COUNT16
+            | TC_CTRLA_PRESCALER_DIV64;
+        tc->COUNT16.WAVE.reg = TC_WAVE_WAVEGEN_MFRQ;
+        #endif
+
+        tc_set_enable(tc, true);
+        //tc->COUNT16.CTRLBSET.reg = TC_CTRLBSET_CMD_STOP;
+        tc->COUNT16.CC[0].reg = 160;
+
+        // Clear our interrupt in case it was set earlier
+        tc->COUNT16.INTFLAG.reg = TC_INTFLAG_MC0;
+        tc->COUNT16.INTENSET.reg = TC_INTENSET_MC0;
+        tc_enable_interrupts(pewpew_tc_index);
+    }
+}
+
+void pew_reset(void) {
+    MP_STATE_VM(pew_singleton) = NULL;
+    pewpew_tc_index = 0xff;
 }
diff --git a/shared-module/_pew/PewPew.h b/shared-module/_pew/PewPew.h
index b21ff0137..2f25f9ce2 100644
--- a/shared-module/_pew/PewPew.h
+++ b/shared-module/_pew/PewPew.h
@@ -29,19 +29,17 @@
 
 #include <stdint.h>
 
-#include "shared-bindings/digitalio/DigitalInOut.h"
-
 typedef struct {
     mp_obj_base_t base;
     uint8_t* buffer;
     mp_obj_t* rows;
     mp_obj_t* cols;
-    size_t rows_size;
-    size_t cols_size;
-    volatile uint8_t col;
-    volatile uint8_t turn;
+    uint8_t rows_size;
+    uint8_t cols_size;
 } pew_obj_t;
 
 void pew_init(void);
+void pewpew_interrupt_handler(uint8_t index);
+void pew_reset(void);
 
 #endif  // MICROPY_INCLUDED_PEW_PEWPEW_H
diff --git a/shared-module/_pew/__init__.c b/shared-module/_pew/__init__.c
index 92637a04d..2e09932f3 100644
--- a/shared-module/_pew/__init__.c
+++ b/shared-module/_pew/__init__.c
@@ -34,39 +34,44 @@
 
 
 void pew_tick(void) {
+    static uint8_t col = 0;
+    static uint8_t turn = 0;
     digitalio_digitalinout_obj_t *pin;
+
     pew_obj_t* pew = MP_STATE_VM(pew_singleton);
     if (!pew) { return; }
 
-    pin = MP_OBJ_TO_PTR(pew->cols[pew->col]);
-    common_hal_digitalio_digitalinout_set_value(pin, true);
-    pew->col += 1;
-    if (pew->col >= pew->cols_size) {
-        pew->col = 0;
-        pew->turn += 1;
-        if (pew->turn >= 4) {
-            pew->turn = 0;
+    pin = MP_OBJ_TO_PTR(pew->cols[col]);
+    ++col;
+    if (col >= pew->cols_size) {
+        col = 0;
+        ++turn;
+        if (turn >= 8) {
+            turn = 0;
         }
     }
+    common_hal_digitalio_digitalinout_set_value(pin, true);
     for (size_t x = 0; x < pew->rows_size; ++x) {
         pin = MP_OBJ_TO_PTR(pew->rows[x]);
-        uint8_t color = pew->buffer[(pew->col) * (pew->rows_size) + x];
-        bool value = true;
-        switch (pew->turn) {
-            case 0:
-                if (color & 0x03) { value = true; }
+        uint8_t color = pew->buffer[col * (pew->rows_size) + x];
+        bool value = false;
+        switch (color & 0x03) {
+            case 3:
+                value = true;
                 break;
-            case 1:
             case 2:
-                if (color & 0x02) { value = true; }
+                if (turn == 2 || turn == 4 || turn == 6) {
+                    value = true;
+                }
+            case 1:
+                if (turn == 0) {
+                    value = true;
+                }
+            case 0:
                 break;
         }
         common_hal_digitalio_digitalinout_set_value(pin, value);
     }
-    pin = MP_OBJ_TO_PTR(pew->cols[pew->col]);
+    pin = MP_OBJ_TO_PTR(pew->cols[col]);
     common_hal_digitalio_digitalinout_set_value(pin, false);
 }
-
-void pew_reset(void) {
-    MP_STATE_VM(pew_singleton) = NULL;
-}
diff --git a/shared-module/_pew/__init__.h b/shared-module/_pew/__init__.h
index 30c9c8c93..f85dec749 100644
--- a/shared-module/_pew/__init__.h
+++ b/shared-module/_pew/__init__.h
@@ -28,6 +28,5 @@
 #define MICROPY_INCLUDED_PEW_H
 
 void pew_tick(void);
-void pew_reset(void);
 
 #endif  // MICROPY_INCLUDED_PEW_H