Initial WIP for TFT (not working yet)

CMakeLists.txt

@@ -53,6 +53,8 @@ target_sources(edmfd PUBLIC
     src/edmfd/main.cc
     src/edmfd/mcp23017.cc
     src/edmfd/screen.cc
+    src/edmfd/spi.cc
+    src/edmfd/tft.cc
     src/edmfd/usb_descriptors.cc
     src/edmfd/vendor.cc
     )
@@ -66,6 +68,7 @@ target_link_libraries(edmfd PUBLIC
     pico_stdio_uart
     pico_unique_id
     hardware_i2c
+    hardware_spi
     tinyusb_device
     tinyusb_board
     )

src/edmfd/main.cc

@@ -14,6 +14,8 @@
 #include "hid.hh"
 #include "i2c.hh"
 #include "mcp23017.hh"
+#include "spi.hh"
+#include "tft.hh"
 
 using mcp23017::reg;
 
@@ -27,11 +29,13 @@ extern "C" {
 }
 
 static constexpr unsigned i2c_baud = 400 * 1000;
+static constexpr unsigned spi_baud = 24 * 1000 * 1000;
 
 static constexpr unsigned hid_update_ms = 1000/20; // 20Hz
 
 static constexpr unsigned bank_leds = 0;
 static constexpr unsigned bank_buttons = 1;
+
 static constexpr unsigned buttons_per_group = 5;
 static constexpr unsigned button_group_count = 2;
 static const unsigned button_group_irqs[] = {4, 7};
@@ -102,6 +106,10 @@ int main(void)
     log::info("board initialized");
 
     i2c::init(i2c_baud);
+    spi::init(spi_baud);
+
+    tft disp {9, 10};
+    disp.init();
 
     // set up interrupt handlers
     for (int pin : button_group_irqs) {

src/edmfd/spi.cc

@@ -0,0 +1,47 @@
+#include "hardware/spi.h"
+#include "pico/stdlib.h"
+#include "pico/binary_info.h"
+
+#include "logging/log.hh"
+
+#include "spi.hh"
+
+namespace spi {
+
+cs::cs(unsigned pin) :
+    pin {pin}
+{
+    asm volatile("nop \n nop \n nop");
+    gpio_put(pin, 0);  // Active low
+    asm volatile("nop \n nop \n nop");
+}
+
+cs::~cs()
+{
+    asm volatile("nop \n nop \n nop");
+    gpio_put(pin, 1);
+    asm volatile("nop \n nop \n nop");
+}
+
+
+void init(unsigned baud)
+{
+    baud = spi_init(spi_default, baud);
+    gpio_set_function(PICO_DEFAULT_SPI_SCK_PIN, GPIO_FUNC_SPI);
+    gpio_set_function(PICO_DEFAULT_SPI_TX_PIN, GPIO_FUNC_SPI);
+    gpio_set_function(PICO_DEFAULT_SPI_RX_PIN, GPIO_FUNC_SPI);
+
+    // Make the SPI pins available to picotool
+    bi_decl(bi_3pins_with_func(PICO_DEFAULT_SPI_RX_PIN, PICO_DEFAULT_SPI_TX_PIN, PICO_DEFAULT_SPI_SCK_PIN, GPIO_FUNC_SPI));
+
+    //spi_set_format(spi_default, 8, SPI_CPOL_0, SPI_CPHA_0, SPI_MSB_FIRST);
+
+    log::info("waiting for spi...");
+
+    while(!spi_is_writable(spi_default));
+
+    log::info("spi initialized at %.1fMHz, SCK=%d TX=%d RX=%d", baud/1000000.f,
+            PICO_DEFAULT_SPI_RX_PIN, PICO_DEFAULT_SPI_TX_PIN, PICO_DEFAULT_SPI_SCK_PIN);
+}
+
+} // namespace spi

src/edmfd/spi.hh

@@ -0,0 +1,17 @@
+#pragma once
+
+namespace spi {
+
+void init(unsigned baud);
+
+// RAII chip select
+class cs
+{
+public:
+    cs(unsigned pin);
+    ~cs();
+private:
+    unsigned pin;
+};
+
+} // namespace spi

src/edmfd/tft.cc

@@ -0,0 +1,185 @@
+#include "hardware/spi.h"
+#include "pico/stdlib.h"
+
+#include "logging/log.hh"
+#include "spi.hh"
+#include "tft.hh"
+
+#include "startup_banner.hh"
+
+enum class cmd : uint8_t {
+    // Organized by datasheet table page
+    // Page 105
+    nop         = 0x00,     // p.114, NOP
+    swreset     = 0x01,     // p.115, Software reset
+    slpin       = 0x10,     // p.131, Sleep in
+    slpout      = 0x11,     // p.133, Sleep out
+
+    // Page 106
+    invoff      = 0x20,     // p.137, Display inversion off
+    invon       = 0x21,     // p.138, Display inversion on
+    dispoff     = 0x28,     // p.142, Display off
+    dispon      = 0x29,     // p.143, Display on
+    caset       = 0x2a,     // p.144, Column address set
+    paset       = 0x2b,     // p.146, Page address set
+    ramwr       = 0x2c,     // p.148, Write VRAM
+
+    // Page 107
+    teoff       = 0x34,     // p.155, Tear effect line off
+    teon        = 0x35,     // p.156, Tear effect line on
+    madctl      = 0x36,     // p.157, Memory access control
+    colmod      = 0x3a,     // p.164, Color mode
+    tesl        = 0x44,     // p.167, Set tear scanline
+
+    // Page 110
+    setosc      = 0xb0,     // p.200, Set internal oscillator
+    setpower    = 0xb1,     // p.201, Set power control
+    setdisplay  = 0xb2,     // p.205, Set display control
+    setrgb      = 0xb3,     // p.207, Set RGB I/F
+    setcyc      = 0xb4,     // p.210, Set display cycle
+    setvcom     = 0xb6,     // p.214, Set VCOM voltage
+    setextc     = 0xb9,     // p.217, Enter extension command
+
+    // Page 111
+    setstba     = 0xc0,     // p.218, Set source option
+    setpanel    = 0xcc,     // p.224, Set panel characteristics
+
+    // Page 112
+    setgamma    = 0xe0,     // p.225, Set gamma
+};
+
+namespace {
+    const uint8_t init_cmds[] = {
+        // SWRESET Soft reset, then delay 10 ms
+        uint8_t(cmd::swreset), 0x80 + 100 / 5,
+
+        // SETEXTC? Set extension command
+        uint8_t(cmd::setextc), 3, 0xFF, 0x83, 0x57,
+
+        // No command, just delay 300 ms (This was 0xff)
+        uint8_t(cmd::nop), 0x80 + 500 / 5,
+
+        // SETRGB -- ?? 0x80 enables SDO pin (0x00 disables)
+        uint8_t(cmd::setrgb), 4, 0x80, 0x00, 0x06, 0x06,
+
+        // SETVCOM -1.52V
+        uint8_t(cmd::setvcom), 1, 0x25,
+
+        // SETOSC  Normal mode 70Hz, Idle mode 55 Hz
+        uint8_t(cmd::setosc), 1, 0x68,
+
+        // SETPANEL  BGR, Gate direction swapped
+        uint8_t(cmd::setpanel), 1, 0x05,
+
+        // SETPOWER  Not deep standby, BT, VSPR, VSNR, AP, FS
+        uint8_t(cmd::setpower), 6, 0x00, 0x15, 0x1C, 0x1C, 0x83, 0xAA,
+
+        // SETSTBA  OPON normal, OPON idle, STBA, STBA, STBA, GEN
+        uint8_t(cmd::setstba), 6, 0x50, 0x50, 0x01, 0x3C, 0x1E, 0x08,
+
+        // SETCYC  NW 2, RTN, DIV, DUM, DUM, GDON, GDOFF
+        uint8_t(cmd::setcyc), 7, 0x02, 0x40, 0x00, 0x2A, 0x2A, 0x0D, 0x78,
+
+        // SETGAMMA
+        uint8_t(cmd::setgamma), 34, 0x02, 0x0A, 0x11, 0x1d, 0x23, 0x35, 0x41, 0x4b, 0x4b, 0x42,
+                  0x3A, 0x27, 0x1B, 0x08, 0x09, 0x03, 0x02, 0x0A, 0x11, 0x1d,
+                  0x23, 0x35, 0x41, 0x4b, 0x4b, 0x42, 0x3A, 0x27, 0x1B, 0x08,
+                  0x09, 0x03, 0x00, 0x01,
+
+        // COLMOD  16 bit color
+        uint8_t(cmd::colmod), 1, 0x55,
+
+        // MADCTL
+        uint8_t(cmd::madctl), 1, 0x00, //0xC0,
+
+        // TEON  TW off
+        uint8_t(cmd::teon), 1, 0x00,
+
+        // TESL (TEARLINE?)
+        uint8_t(cmd::tesl), 2, 0x00, 0x02,
+
+        // SLPOUT  Exit Sleep, then delay 150 ms
+        uint8_t(cmd::slpout), 0x80 + 150 / 5,
+
+        // DISPON  Main screen turn on, delay 50 ms
+        uint8_t(cmd::dispon), 0x80 + 50 / 5,
+
+        // End of commands
+        0, 0
+    };
+} // namespace
+
+void tft::init()
+{
+    gpio_init(m_cs);
+    gpio_set_dir(m_cs, GPIO_OUT);
+    gpio_put(m_cs, 1); // Initialize to 1 (unselected)
+
+    gpio_init(m_dc);
+    gpio_set_dir(m_dc, GPIO_OUT);
+    gpio_put(m_dc, 1); // Initialize to 1 (data mode)
+
+
+    {
+        spi::cs {m_cs};
+        uint8_t buf[64];
+        uint8_t const *commands = init_cmds;
+        const uint8_t *end = init_cmds + sizeof(init_cmds);
+        while (commands < end) {
+            cmd command = static_cast<cmd>(*commands++);
+            uint8_t nargs = *commands++;
+            if (command == cmd::nop && !nargs) break;
+
+            // If high bit is set, this is a delay
+            unsigned delay = (nargs & 0x80) ? (unsigned(nargs & 0x7f) * 5) : 0;
+            nargs = (nargs & 0x80) ? 0 : (nargs & 0x7f);
+
+            for (unsigned i = 0; i < nargs; ++i)
+                buf[i] = *commands++;
+
+            if (command != cmd::nop)
+                write_command(command, buf, nargs);
+
+            if (delay) {
+            log::trace("Delay %dms", delay);
+                sleep_ms(delay);
+            }
+        }
+    }
+
+    {
+        spi::cs {m_cs};
+        uint16_t w = 480/3;
+        uint16_t h = 320/3;
+        unsigned n = w*h;
+        uint16_t color = __builtin_bswap16(startup_color);
+        //color = 0xffff;
+        color = 0xf800;
+        log::info("Drawing %dx%d square, color %04x", w, h, color);
+        set_draw_rect(0, 0, w, h);
+        for (unsigned i = 0; i < n; ++i)
+            spi_write_blocking(spi_default, reinterpret_cast<uint8_t*>(&color), sizeof(color));
+        log::trace("Wrote SPI %d data bytes", n);
+    }
+}
+
+void tft::write_command(cmd command, uint8_t *args, unsigned args_len)
+{
+    {
+        spi::cs {m_dc}; // Command Mode
+        spi_write_blocking(spi_default, reinterpret_cast<uint8_t*>(&command), sizeof(command));
+    }
+
+    if (args_len)
+        spi_write_blocking(spi_default, args, args_len);
+    log::trace("Wrote SPI command %02x, %d data bytes", command, args_len);
+}
+
+void tft::set_draw_rect(uint16_t x, uint16_t y, uint16_t w, uint16_t h)
+{
+    uint16_t xargs[2] = { __builtin_bswap16(x), __builtin_bswap16(x + w - 1) };
+    uint16_t yargs[2] = { __builtin_bswap16(y), __builtin_bswap16(y + h - 1) };
+    write_command(cmd::caset, reinterpret_cast<uint8_t*>(&xargs), sizeof(xargs));
+    write_command(cmd::paset, reinterpret_cast<uint8_t*>(&yargs), sizeof(yargs));
+    write_command(cmd::ramwr);
+}

src/edmfd/tft.hh

@@ -0,0 +1,18 @@
+#pragma once
+
+enum class cmd : uint8_t;
+
+class tft
+{
+public:
+    tft(unsigned cs, unsigned dc) :
+        m_cs {cs}, m_dc {dc} {}
+
+    void init();
+
+private:
+    void write_command(cmd command, uint8_t *args = nullptr, unsigned args_len = 0);
+    void set_draw_rect(uint16_t x, uint16_t y, uint16_t w, uint16_t h);
+
+    unsigned m_cs, m_dc;
+};