can: add basic heartbeat (untested)

firmware/lib/can2040/src/can2040.c

@@ -8,7 +8,8 @@
 #include <string.h> // memset
 // NOTE: This was changed from the original checkout
 // #include "RP2040.h" // hw_set_bits
-#include "hardware/address_mapped.h" // hw_set_bits
+#include "hardware/address_mapped.h" // hw_set_bit
+#include "cmsis_gcc.h" // NOTE: this was added for _DMB() to build
 #include "can2040.h" // can2040_setup
 #include "hardware/regs/dreq.h" // DREQ_PIO0_RX1
 #include "hardware/structs/dma.h" // dma_hw

firmware/src/can.cpp

@@ -0,0 +1,54 @@
+#include <Arduino.h>
+#include "config.h"
+#include "can.h"
+
+static void can2040_callback(struct can2040 *cd, uint32_t notify, struct can2040_msg *msg) {
+}
+
+static void canbus_pio_irq_handler() {
+  can2040_pio_irq_handler(&canbus);
+}
+
+void canbus_setup() {
+  uint32_t pio_num = 1;
+  can2040_setup(&canbus, pio_num);
+  can2040_callback_config(&canbus, can2040_callback);
+
+  irq_set_exclusive_handler(PIO1_IRQ_0, canbus_pio_irq_handler);
+  irq_set_priority(PIO1_IRQ_0, 1);
+  irq_set_enabled(PIO1_IRQ_0, true);
+
+  can2040_start(&canbus, CPU_CLOCK_HZ, CAN_BITRATE, CAN_PIN_RX, CAN_PIN_TX);
+}
+
+unsigned long canbus_last_heartbeat_at = 0;
+int canbus_heartbeat_interval = 1000;
+void canbus_heartbeat();
+
+void canbus_loop() {
+  auto now = millis();
+  if (canbus_last_heartbeat_at + canbus_heartbeat_interval < now) {
+    canbus_last_heartbeat_at = now;
+    // add some jitter to reduce collision likelihood
+    canbus_heartbeat_interval = 1000 + random(-200, 200);
+    canbus_heartbeat();
+  }
+}
+
+void canbus_heartbeat() {
+  int device_id = 224;
+  int msg_kind = 31;
+  int msg_type = 31;
+
+  // {kind:5}{device:8}{type:5}{reserved:11}
+  uint32_t id = CAN2040_ID_EFF | ((msg_kind << (8 + 5)) | (device_id << 5) | msg_type) << 11;
+
+  can2040_msg msg = {
+    .id = id,
+    .dlc = 0,
+  };
+  auto result = can2040_transmit(&canbus, &msg);
+  if (result != 0) {
+    Serial.println("CAN: heartbeat failed");
+  }
+}

firmware/src/can.h

@@ -0,0 +1,15 @@
+#pragma once
+
+#ifndef _can_h
+#define _can_h
+
+extern "C" {
+  #include "can2040.h"
+}
+
+static struct can2040 canbus;
+
+void canbus_setup();
+void canbus_loop();
+
+#endif

firmware/src/config.h

@@ -48,6 +48,12 @@
 #define ROW_SRCLK 18
 // #define ROW_SRCLR 15
 
+#define COL_SER_INVERTED false // double inverted
+#define COL_OE_INVERTED true
+#define COL_RCLK_INVERTED true
+#define COL_SRCLK_INVERTED true
+#define COL_SRCLR_INVERTED false
+
 // --- screen settings ---
 
 #define ROW_MODULES 2
@@ -71,6 +77,7 @@
 #define CPU_CLOCK_HZ 125000000.0f
 #define SD_CARD_BAUD_RATE 10 * 1000 * 1000
 #define REFERENCE_VOLTAGE 3.3f // for ADC
+#define CAN_BITRATE 500000
 
 // --- debug settings ---
 

firmware/src/leds.cpp

@@ -141,6 +141,23 @@ void leds_init() {
   pinMode(ROW_SRCLK, OUTPUT);
   pinMode(ROW_SRCLR, OUTPUT);
 
+  // set pin inversion
+  #if COL_SER_INVERTED
+  gpio_set_outover(COL_SER, GPIO_OVERRIDE_INVERT);
+  #endif
+  #if COL_OE_INVERTED
+  gpio_set_outover(COL_OE, GPIO_OVERRIDE_INVERT);
+  #endif
+  #if COL_RCLK_INVERTED
+  gpio_set_outover(COL_RCLK, GPIO_OVERRIDE_INVERT);
+  #endif
+  #if COL_SRCLK_INVERTED
+  gpio_set_outover(COL_SRCLK, GPIO_OVERRIDE_INVERT);
+  #endif
+  #if COL_SRCLR_INVERTED
+  gpio_set_outover(COL_SRCLR, GPIO_OVERRIDE_INVERT);
+  #endif
+
   // clear output
   clearShiftReg(COL_SRCLK, COL_SRCLR);
   clearShiftReg(ROW_SRCLK, ROW_SRCLR);
@@ -238,18 +255,15 @@ void leds_initPusher() {
   pio_gpio_init(pio, COL_SER);
   pio_sm_set_consecutive_pindirs(pio, sm, COL_SER, 1, true);
 
-  // data is inverted
-  gpio_set_outover(COL_SER, GPIO_OVERRIDE_INVERT);
-
   // Set sideset (SRCLK) pin, connect to pad, set as output
   sm_config_set_sideset_pins(&config, COL_SRCLK);
   pio_gpio_init(pio, COL_SRCLK);
   pio_sm_set_consecutive_pindirs(pio, sm, COL_SRCLK, 1, true);
 
   // Set SET (RCLK) pin, connect to pad, set as output
-  sm_config_set_set_pins(&config, ROW_RCLK, 1);
-  pio_gpio_init(pio, ROW_RCLK);
-  pio_sm_set_consecutive_pindirs(pio, sm, ROW_RCLK, 1, true);
+  sm_config_set_set_pins(&config, COL_RCLK, 1);
+  pio_gpio_init(pio, COL_RCLK);
+  pio_sm_set_consecutive_pindirs(pio, sm, COL_RCLK, 1, true);
 
   // Load our configuration, and jump to the start of the program
   pio_sm_init(pio, sm, offset, &config);
@@ -269,9 +283,8 @@ void leds_initRowSelector() {
   // Shift OSR to the right, autopull
   sm_config_set_out_shift(&config, true, true, 32);
 
-  // Set OUT and SET (data) pin, connect to pad, set as output
+  // Set OUT/MOV (data) pin, connect to pad, set as output
   sm_config_set_out_pins(&config, ROW_SER, 1);
-  sm_config_set_set_pins(&config, ROW_SER, 1);
   pio_gpio_init(pio, ROW_SER);
   pio_sm_set_consecutive_pindirs(pio, sm, ROW_SER, 1, true);
 
@@ -280,6 +293,11 @@ void leds_initRowSelector() {
   pio_gpio_init(pio, ROW_SRCLK);
   pio_sm_set_consecutive_pindirs(pio, sm, ROW_SRCLK, 1, true);
 
+  // Set SET (RCLK) pin, connect to pad, set as output
+  sm_config_set_set_pins(&config, ROW_RCLK, 1);
+  pio_gpio_init(pio, ROW_RCLK);
+  pio_sm_set_consecutive_pindirs(pio, sm, ROW_RCLK, 1, true);
+
   // Load our configuration, and jump to the start of the program
   pio_sm_init(pio, sm, offset, &config);
   pio_sm_set_enabled(pio, sm, true);

firmware/src/leds.pio

@@ -1,14 +1,14 @@
-.define public irq_did_latch 0
-.define public irq_row_selected 1
-.define public irq_delaying 2
+.define public irq_delaying 0
+.define public irq_px_pushed 1
+.define public irq_rclk_sync 2
+.define public irq_did_latch 3
 
-; TODO: check if delays can be lowered with a PCB
-.define public srclk_0_delay 1
-.define public srclk_1_delay 2
 .define public rclk_1_delay 3
 
 .program leds_px_pusher
 .side_set 1 opt
+.define public srclk_0_delay 1
+.define public srclk_1_delay 2
 entry_point:
 .wrap_target
   ; get 32 bits from fifo (not required with autopull, useful for debug)
@@ -29,13 +29,13 @@ end:
   ; MSB=1 indicates end of row
   jmp !x entry_point
 end_of_row:
+  ; pixels pushed - can begin row selection
+  irq set irq_px_pushed
   ; wait until previous row's delay is complete
   ; (irq will be 0 on first row by default)
   wait 0 irq irq_delaying
-  ; wait until row is selected, and clear flag
-  wait 1 irq irq_row_selected
-  ; signal that we're about to latch the row onto display
-  irq set irq_did_latch
+  ; synchronize ROW_RCLK and COL_RCLK - note that the delays MUST be the same
+  wait 1 irq irq_rclk_sync
   ; clock RCLK (latch onto register output stage)
   set pins, 1                           [rclk_1_delay]
   set pins, 0
@@ -44,22 +44,31 @@ end_of_row:
 
 .program leds_row_selector
 .side_set 1 opt
+.define public srclk_0_delay 1
+.define public srclk_1_delay 2
 entry_point:
 .wrap_target
+  ; wait until pixels are pushed
+  ; (NOTE: This can happen in parallel if ROW_SER and COL_SER are separate)
+  wait 1 irq irq_px_pushed
   ; LSB=1 indicates first (bottom) row, ergo, high SER for the first pulse
   out pins, 1                   side 0  [srclk_0_delay]
   ; The rest of the word indicates number of extra SRCLK pulses
   out x, 31
 loop:
   ; pulse SRCLK x times
-  ; set SER=0 after first pulse
   nop                           side 1  [srclk_1_delay]
-  set pins, 0                   side 0  [srclk_0_delay]
+  ; set SER=0 after first pulse
+  mov pins, null                side 0  [srclk_0_delay]
   jmp x-- loop
 end:
-  ; signal that row is selected and wait until acknowledged
-  ; some delay so that in the worst case scenario we don't start changing rows before RCLK latch
-  irq wait irq_row_selected             [4]
+  ; synchronize ROW_RCLK and COL_RCLK - note that the delays MUST be the same
+  irq wait irq_rclk_sync
+  ; clock RCLK (latch onto register output stage)
+  set pins, 1                           [rclk_1_delay]
+  ; signal that rclk had latched (delay/oe can begin)
+  irq set irq_did_latch
+  set pins, 0
   .wrap
 
 .program leds_delay

firmware/src/leds.pio.h

@@ -8,11 +8,10 @@
 #include "hardware/pio.h"
 #endif
 
-#define irq_did_latch 0
-#define irq_row_selected 1
-#define irq_delaying 2
-#define srclk_0_delay 1
-#define srclk_1_delay 2
+#define irq_delaying 0
+#define irq_px_pushed 1
+#define irq_rclk_sync 2
+#define irq_did_latch 3
 #define rclk_1_delay 3
 
 // -------------- //
@@ -22,6 +21,9 @@
 #define leds_px_pusher_wrap_target 0
 #define leds_px_pusher_wrap 9
 
+#define leds_px_pusher_srclk_0_delay 1
+#define leds_px_pusher_srclk_1_delay 2
+
 static const uint16_t leds_px_pusher_program_instructions[] = {
             //     .wrap_target
     0xf037, //  0: set    x, 23           side 0     
@@ -29,9 +31,9 @@ static const uint16_t leds_px_pusher_program_instructions[] = {
     0x1a41, //  2: jmp    x--, 1          side 1 [2] 
     0x7028, //  3: out    x, 8            side 0     
     0x0020, //  4: jmp    !x, 0                      
-    0x2042, //  5: wait   0 irq, 2                   
-    0x20c1, //  6: wait   1 irq, 1                   
-    0xc000, //  7: irq    nowait 0                   
+    0xc001, //  5: irq    nowait 1                   
+    0x2040, //  6: wait   0 irq, 0                   
+    0x20c2, //  7: wait   1 irq, 2                   
     0xe301, //  8: set    pins, 1                [3] 
     0xe000, //  9: set    pins, 0                    
             //     .wrap
@@ -57,23 +59,30 @@ static inline pio_sm_config leds_px_pusher_program_get_default_config(uint offse
 // ----------------- //
 
 #define leds_row_selector_wrap_target 0
-#define leds_row_selector_wrap 5
+#define leds_row_selector_wrap 9
+
+#define leds_row_selector_srclk_0_delay 1
+#define leds_row_selector_srclk_1_delay 2
 
 static const uint16_t leds_row_selector_program_instructions[] = {
             //     .wrap_target
-    0x7101, //  0: out    pins, 1         side 0 [1] 
-    0x603f, //  1: out    x, 31                      
-    0xba42, //  2: nop                    side 1 [2] 
-    0xf100, //  3: set    pins, 0         side 0 [1] 
-    0x0042, //  4: jmp    x--, 2                     
-    0xc421, //  5: irq    wait 1                 [4] 
+    0x20c1, //  0: wait   1 irq, 1                   
+    0x7101, //  1: out    pins, 1         side 0 [1] 
+    0x603f, //  2: out    x, 31                      
+    0xba42, //  3: nop                    side 1 [2] 
+    0xb103, //  4: mov    pins, null      side 0 [1] 
+    0x0043, //  5: jmp    x--, 3                     
+    0xc022, //  6: irq    wait 2                     
+    0xe301, //  7: set    pins, 1                [3] 
+    0xc003, //  8: irq    nowait 3                   
+    0xe000, //  9: set    pins, 0                    
             //     .wrap
 };
 
 #if !PICO_NO_HARDWARE
 static const struct pio_program leds_row_selector_program = {
     .instructions = leds_row_selector_program_instructions,
-    .length = 6,
+    .length = 10,
     .origin = -1,
 };
 
@@ -97,11 +106,11 @@ static inline pio_sm_config leds_row_selector_program_get_default_config(uint of
 
 static const uint16_t leds_delay_program_instructions[] = {
             //     .wrap_target
-    0x20c0, //  0: wait   1 irq, 0                   
-    0xc002, //  1: irq    nowait 2                   
+    0x20c3, //  0: wait   1 irq, 3                   
+    0xc000, //  1: irq    nowait 0                   
     0x6020, //  2: out    x, 32                      
     0x1043, //  3: jmp    x--, 3          side 0     
-    0xd842, //  4: irq    clear 2         side 1     
+    0xd840, //  4: irq    clear 0         side 1     
             //     .wrap
 };
 

firmware/src/main.cpp

@@ -20,6 +20,10 @@ void setup() {
   init_audio();
   leds_initRenderer();
 
+  #if CAN_ENABLED
+  canbus_setup();
+  #endif
+
   #if SD_HAS_DETECTION
   while (!isSDCardInserted()) {
     Serial.println("SD card not connected, waiting...");
@@ -100,4 +104,8 @@ void loop() {
       nextSong();
     }
   }
+
+  #if CAN_ENABLED
+  canbus_loop();
+  #endif
 }