Support for Waveshare RP2040-Zero

src/rp2040/CMakeLists.txt

@@ -1,3 +1,6 @@
+# to build for waveshare rp2040-zero do
+# cmake -DWS2040_ZERO=ON ..
+
 cmake_minimum_required(VERSION 3.13)
 
 set(PROJECT fpga_companion)
@@ -47,6 +50,21 @@ family_add_pico_pio_usb(${PROJECT})
 target_compile_definitions(${PROJECT} PRIVATE
         PIO_USB_DP_PIN_DEFAULT=2
         )
+
+option(WS2040_ZERO "Build for Waveshare RP2040-Zero" OFF) # Regular Pico by default
+if(WS2040_ZERO)
+        add_compile_definitions(${PROJECT} PRIVATE WAVESHARE_RP2040_ZERO=1)
+        add_custom_command(TARGET ${PROJECT} POST_BUILD COMMAND ${CMAKE_COMMAND} -E cmake_echo_color --cyan "Firmware has been built for Waveshare RP2040-Zero.")
+else(WS2040_ZERO)
+        add_custom_command(TARGET ${PROJECT} POST_BUILD COMMAND ${CMAKE_COMMAND} -E cmake_echo_color --cyan "Firmware has been built for Raspberry Pi Pico or Pico-W.")
+endif(WS2040_ZERO)
+
+target_include_directories(${PROJECT} PRIVATE
+      ${CMAKE_CURRENT_LIST_DIR}
+      ${CMAKE_CURRENT_LIST_DIR}/../fatfs/source
+      ${CMAKE_CURRENT_LIST_DIR}/../u8g2/csrc
+      ${CMAKE_CURRENT_LIST_DIR}/../tusb_xinput
+)
 
 target_include_directories(${PROJECT} PRIVATE
       ${CMAKE_CURRENT_LIST_DIR}

src/rp2040/README.md

@@ -95,6 +95,43 @@ To use this you need a micro-USB to USB-A-OTG adapter.
 
 ![Tang Nano 20k with Raspberry Pi Pico](pico_tn20k.png)
 
+# Using the Waveshare RP2040-Zero
+
+The Raspberry Pi Pico is rather big and only comes with a Micro USB
+port. The [Waveshare RP2040-Zero](https://www.waveshare.com/rp2040-zero.htm) is a little
+smaller and comes with a USB-C connector which makes it easier to use
+it as a USB host using a regular USB-C to USB-A host adapter.
+
+To build the firmware for the RP2040-Zero use the following
+command:
+
+```
+cmake -DWS2040_ZERO=ON ..
+```
+
+The build process will then end with the following message:
+
+```
+Firmware has been built for Waveshare RP2040-Zero.
+```
+
+The SPI pins used on the RP2040-Zero differ from the ones used on the
+regular pico:
+
+| Pin | Signal | Description |
+|---|---|---|
+| GP0  | UART_TX  | Serial debug output |
+| GP4 | MISO | SPI data from FPGA |
+| GP5 | CSn | SPI chip select to FPGA |
+| GP6 | SCK | SPI clock to FPGA |
+| GP7 | MOSI | SPI data to FPGA |
+| GP8 | IRQn | SPI interrupt from FPGA |
+
+Also the RP2040-Zero comes with a WS2812 RGB led instead of a regular
+LED. Driving the RGB LED requies a PIO unit and thus cannot be used at
+the same time as the PIO-USB. The native USB of the RP2040-Zero must
+therefore always be used, anyway.
+
 # Convenient development
 
 The RP2040 is by default somewhat inconvenient to develop for

src/rp2040/mcu_hw.c

@@ -22,6 +22,34 @@
 
 #include "../mcu_hw.h"
 
+#ifdef WAVESHARE_RP2040_ZERO
+#warning "Building for Waveshare RP2040-Zero mini board"
+
+// the waveshare mini does not expose the default spi0 pins, so we need
+// to specify them
+#define SPI_RX_PIN    4
+#define SPI_SCK_PIN   6
+#define SPI_TX_PIN    7
+#define SPI_CSN_PIN   5
+#define SPI_IRQ_PIN   8
+#define SPI_BUS  spi0
+#define WS2812_PIN    16
+#else
+#warning "Building for Pi Pico and Pico(W)"
+
+// the regular pi pico uses spi0 by default
+#define SPI_RX_PIN   PICO_DEFAULT_SPI_RX_PIN
+#define SPI_SCK_PIN  PICO_DEFAULT_SPI_SCK_PIN
+#define SPI_TX_PIN   PICO_DEFAULT_SPI_TX_PIN
+#define SPI_CSN_PIN  PICO_DEFAULT_SPI_CSN_PIN
+#define SPI_IRQ_PIN  22
+#define SPI_BUS  spi_default
+#endif
+
+#ifdef WS2812_PIN
+#include "ws2812.pio.h"
+#endif
+
 /* ============================================================================================= */
 /* ===============                          USB                                   ============== */
 /* ============================================================================================= */
@@ -38,6 +66,11 @@
 #error "Please update your TinyUSB installation!"
 #endif
 
+#include "tusb_config.h"
+#if defined(WS2812_PIN) && CFG_TUH_RPI_PIO_USB == 1
+#error "WS2812B and PIO USB cannot be used simultaneously!"
+#endif
+
 static struct {
   uint8_t dev_addr;
   uint8_t instance;
@@ -137,7 +170,7 @@ static SemaphoreHandle_t sem;
 
 static void irq_handler(void) {
   // Disable interrupt. It will be re-enabled by the com task
-  gpio_set_irq_enabled(22, GPIO_IRQ_LEVEL_LOW, false);
+  gpio_set_irq_enabled(SPI_IRQ_PIN, GPIO_IRQ_LEVEL_LOW, false);
 
   if(com_task_handle) {
     BaseType_t xHigherPriorityTaskWoken = pdFALSE;
@@ -152,27 +185,27 @@ void mcu_hw_spi_init(void) {
   sem = xSemaphoreCreateMutex();
 
   // init SPI at 20Mhz, mode 1
-  spi_init(spi_default, 20000000);
-  spi_set_format(spi_default, 8, SPI_CPOL_0, SPI_CPHA_1, SPI_MSB_FIRST);
+  spi_init(SPI_BUS, 20000000);
+  spi_set_format(SPI_BUS, 8, SPI_CPOL_0, SPI_CPHA_1, SPI_MSB_FIRST);
 
-  debugf("  MISO = %d", PICO_DEFAULT_SPI_RX_PIN);
-  gpio_set_function(PICO_DEFAULT_SPI_RX_PIN, GPIO_FUNC_SPI);
-  debugf("  SCK  = %d", PICO_DEFAULT_SPI_SCK_PIN);
-  gpio_set_function(PICO_DEFAULT_SPI_SCK_PIN, GPIO_FUNC_SPI);
-  debugf("  MOSI = %d", PICO_DEFAULT_SPI_TX_PIN);
-  gpio_set_function(PICO_DEFAULT_SPI_TX_PIN, GPIO_FUNC_SPI);
+  debugf("  MISO = %d", SPI_RX_PIN);
+  gpio_set_function(SPI_RX_PIN, GPIO_FUNC_SPI);
+  debugf("  SCK  = %d", SPI_SCK_PIN);
+  gpio_set_function(SPI_SCK_PIN, GPIO_FUNC_SPI);
+  debugf("  MOSI = %d", SPI_TX_PIN);
+  gpio_set_function(SPI_TX_PIN, GPIO_FUNC_SPI);
 
   // Chip select is active-low, so we'll initialise it to a driven-high state
-  debugf("  CSn  = %d", PICO_DEFAULT_SPI_CSN_PIN);
-  gpio_init(PICO_DEFAULT_SPI_CSN_PIN);
-  gpio_set_dir(PICO_DEFAULT_SPI_CSN_PIN, GPIO_OUT);
-  gpio_put(PICO_DEFAULT_SPI_CSN_PIN, 1);
+  debugf("  CSn  = %d", SPI_CSN_PIN);
+  gpio_init(SPI_CSN_PIN);
+  gpio_set_dir(SPI_CSN_PIN, GPIO_OUT);
+  gpio_put(SPI_CSN_PIN, 1);
 
   // The interruput input isn't strictly part of the SPi
   // The interrupt is active low on GP22
-  debugf("  IRQn = %d", 22);
-  // set handler but not enable yet as the main task may not be ready  
-  gpio_add_raw_irq_handler(22, irq_handler);  
+  debugf("  IRQn = %d", SPI_IRQ_PIN);
+  // set handler but not enable yet as the main task may not be ready
+  gpio_add_raw_irq_handler(SPI_IRQ_PIN, irq_handler);
 }
 
 void mcu_hw_irq_ack(void) {
@@ -185,22 +218,22 @@ void mcu_hw_irq_ack(void) {
   }
 
   // re-enable the interrupt since it was now serviced outside the irq handler
-  gpio_set_irq_enabled(22, GPIO_IRQ_LEVEL_LOW, 1); 
+  gpio_set_irq_enabled(SPI_IRQ_PIN, GPIO_IRQ_LEVEL_LOW, 1); 
 }
 
 void mcu_hw_spi_begin() {
   xSemaphoreTake(sem, 0xffffffffUL);      // wait forever
-  gpio_put(PICO_DEFAULT_SPI_CSN_PIN, 0);  // Active low
+  gpio_put(SPI_CSN_PIN, 0);  // Active low
 }
 
 void mcu_hw_spi_end() {
-  gpio_put(PICO_DEFAULT_SPI_CSN_PIN, 1);
+  gpio_put(SPI_CSN_PIN, 1);
   xSemaphoreGive(sem);
 }
 
 unsigned char mcu_hw_spi_tx_u08(unsigned char b) {
   unsigned char retval;
-  spi_write_read_blocking(spi_default, &b, &retval, 1);
+  spi_write_read_blocking(SPI_BUS, &b, &retval, 1);
   return retval;
 }
 
@@ -215,12 +248,21 @@ void mcu_hw_init(void) {
   stdio_init_all();    // ... so stdio can adjust its bit rate
 
   printf("\r\n\r\n" LOGO "           FPGA Companion for RP2040\r\n\r\n");
+#if CFG_TUH_RPI_PIO_USB == 0
+  printf("Using native USB\r\n");
+#else
   printf("USB D+/D- on GP%d and GP%d\r\n", PIO_USB_DP_PIN_DEFAULT, PIO_USB_DP_PIN_DEFAULT+1);
-
+#endif
+
+#ifdef WS2812_PIN
+  uint offset = pio_add_program(pio0, &ws2812_program);  
+  ws2812_program_init(pio0, 0, offset, WS2812_PIN, 800000, 0);
+#else
   gpio_init(PICO_DEFAULT_LED_PIN);
   gpio_set_dir(PICO_DEFAULT_LED_PIN, 1);
   gpio_put(PICO_DEFAULT_LED_PIN, !PICO_DEFAULT_LED_PIN_INVERTED);
-
+#endif
+
   mcu_hw_spi_init();
 
   tuh_init(BOARD_TUH_RHPORT);
@@ -363,10 +405,18 @@ void vApplicationIdleHook( void ) {
 
 void vApplicationTickHook( void ) { }
 
+#ifdef WS2812_PIN
+static void led_timer(__attribute__((unused)) TimerHandle_t pxTimer) {
+  static char state = 0;
+  pio_sm_put_blocking(pio0, 0, state?0xff000000:0x00000000);  // GRBX
+  state = !state;
+}
+#else
 static void led_timer(__attribute__((unused)) TimerHandle_t pxTimer) {
   gpio_xor_mask( 1u << PICO_DEFAULT_LED_PIN );
 }
-
+#endif
+
 void mcu_hw_main_loop(void) {
   TimerHandle_t led_timer_handle = xTimerCreate("LED timer", pdMS_TO_TICKS(200), pdTRUE,
 						NULL, led_timer);

src/rp2040/tusb_config.h

@@ -34,13 +34,18 @@
 // Board Specific Configuration
 //--------------------------------------------------------------------+
 
-#if CFG_TUSB_MCU == OPT_MCU_RP2040
+#ifdef WAVESHARE_RP2040_ZERO
+// the waveshare rp2040 zero comes with a convenient USB-C connector
+// and PIO USB would collide with PIO-WS2812, so this never uses PIO USB
+#define CFG_TUH_RPI_PIO_USB   0
+#else   
 // change to 0 if using on-board native micro USB
 // change to 1 if using pico-pio-usb as host controller for raspberry rp2040
 #define CFG_TUH_RPI_PIO_USB   1
-#define BOARD_TUH_RHPORT      CFG_TUH_RPI_PIO_USB
 #endif
 
+#define BOARD_TUH_RHPORT      CFG_TUH_RPI_PIO_USB
+
 // RHPort number used for host can be defined by board.mk, default to port 0
 #ifndef BOARD_TUH_RHPORT
 #define BOARD_TUH_RHPORT      0

src/rp2040/ws2812.pio.h

@@ -0,0 +1,66 @@
+// -------------------------------------------------- //
+// This file is autogenerated by pioasm; do not edit! //
+// -------------------------------------------------- //
+
+#pragma once
+
+#if !PICO_NO_HARDWARE
+#include "hardware/pio.h"
+#endif
+
+// ------ //
+// ws2812 //
+// ------ //
+
+#define ws2812_wrap_target 0
+#define ws2812_wrap 3
+#define ws2812_pio_version 0
+
+#define ws2812_T1 2
+#define ws2812_T2 5
+#define ws2812_T3 3
+
+static const uint16_t ws2812_program_instructions[] = {
+            //     .wrap_target
+    0x6221, //  0: out    x, 1            side 0 [2] 
+    0x1123, //  1: jmp    !x, 3           side 1 [1] 
+    0x1400, //  2: jmp    0               side 1 [4] 
+    0xa442, //  3: nop                    side 0 [4] 
+            //     .wrap
+};
+
+#if !PICO_NO_HARDWARE
+static const struct pio_program ws2812_program = {
+    .instructions = ws2812_program_instructions,
+    .length = 4,
+    .origin = -1,
+    //    .pio_version = 0,
+#if PICO_PIO_VERSION > 0
+    .used_gpio_ranges = 0x0
+#endif
+};
+
+static inline pio_sm_config ws2812_program_get_default_config(uint offset) {
+    pio_sm_config c = pio_get_default_sm_config();
+    sm_config_set_wrap(&c, offset + ws2812_wrap_target, offset + ws2812_wrap);
+    sm_config_set_sideset(&c, 1, false, false);
+    return c;
+}
+
+#include "hardware/clocks.h"
+static inline void ws2812_program_init(PIO pio, uint sm, uint offset, uint pin, float freq, bool rgbw) {
+    pio_gpio_init(pio, pin);
+    pio_sm_set_consecutive_pindirs(pio, sm, pin, 1, true);
+    pio_sm_config c = ws2812_program_get_default_config(offset);
+    sm_config_set_sideset_pins(&c, pin);
+    sm_config_set_out_shift(&c, false, true, rgbw ? 32 : 24);
+    sm_config_set_fifo_join(&c, PIO_FIFO_JOIN_TX);
+    int cycles_per_bit = ws2812_T1 + ws2812_T2 + ws2812_T3;
+    float div = clock_get_hz(clk_sys) / (freq * cycles_per_bit);
+    sm_config_set_clkdiv(&c, div);
+    pio_sm_init(pio, sm, offset, &c);
+    pio_sm_set_enabled(pio, sm, true);
+}
+
+#endif
+