diff --git a/README.md b/README.md
index a648910..c0c93c8 100644
--- a/README.md
+++ b/README.md
@@ -132,6 +132,13 @@ Pass through UART from host to the ESP8285 WIFI chip.
 
 [README](rust/uart-passthrough/README.md)
 
+rust/rgbcontrol
+----------------
+
+Control the color of the RGB LED from the touch screen.
+
+[README](rust/rgbcontrol/README.md)
+
 ROM re'ing
 ===========
 
diff --git a/rust/accelerometer/.cargo/config b/rust/.cargo/config
similarity index 100%
rename from rust/accelerometer/.cargo/config
rename to rust/.cargo/config
diff --git a/rust/Cargo.toml b/rust/Cargo.toml
index c68c5fa..1c9745a 100644
--- a/rust/Cargo.toml
+++ b/rust/Cargo.toml
@@ -5,6 +5,7 @@ members = [
     "game-of-life",
     "accelerometer",
     "uart-passthrough",
+    "rgbcontrol",
 ]
 
 [patch.crates-io]
diff --git a/rust/accelerometer/src/main.rs b/rust/accelerometer/src/main.rs
index 1bc8cf2..04b2a33 100644
--- a/rust/accelerometer/src/main.rs
+++ b/rust/accelerometer/src/main.rs
@@ -8,8 +8,9 @@ use k210_hal::pac;
 use k210_hal::prelude::*;
 use k210_hal::stdout::Stdout;
 use k210_shared::board::def::{io,DISP_WIDTH,DISP_HEIGHT,MSA300_SLV_ADDR,MSA300_ADDR_BITS,MSA300_CLK};
-use k210_shared::board::lcd::{LCD,self};
+use k210_shared::board::lcd::{LCD,LCDHL,self};
 use k210_shared::board::lcd_colors;
+use k210_shared::board::lcd_render::render_image;
 use k210_shared::board::msa300::Accelerometer;
 use k210_shared::soc::fpioa;
 use k210_shared::soc::i2c::{I2C,I2CExt};
@@ -23,12 +24,6 @@ pub const BLK_SIZE: usize = 8;
 pub const GRID_WIDTH: usize = DISP_WIDTH / BLK_SIZE;
 pub const GRID_HEIGHT: usize = DISP_HEIGHT / BLK_SIZE;
 
-/** Array for representing an image of the entire screen.
- * This is an array of DISP_WIDTH / 2 × DISP_HEIGHT, each two horizontally consecutive
- * pixels are encoded in a u32 with `(a << 16)|b`.
- */
-pub type ScreenImage = [u32; DISP_WIDTH * DISP_HEIGHT / 2];
-
 /** Connect pins to internal functions */
 fn io_mux_init() {
     /* Init SPI IO map and function settings */
@@ -82,8 +77,6 @@ fn main() -> ! {
     lcd.set_direction(lcd::direction::YX_LRUD);
     lcd.clear(lcd_colors::PURPLE);
 
-    let mut image: ScreenImage = [0; DISP_WIDTH * DISP_HEIGHT / 2];
-
     writeln!(stdout, "MSA300 init").unwrap();
     let i2c = p.I2C0.constrain();
     i2c.init(MSA300_SLV_ADDR, MSA300_ADDR_BITS, MSA300_CLK);
@@ -99,17 +92,13 @@ fn main() -> ! {
         let cy = ((x/8.5 + 1.0) * ((DISP_HEIGHT / 2) as f32)) as i32;
         let r = (1.5*mag) as i32;
         let rr = r * r;
-        let mut idx = 0;
-        for y in 0..DISP_HEIGHT as i32 {
-            for x2 in 0..(DISP_WIDTH/2) as i32 {
-                let x = x2 * 2;
-                image[idx] = (if sample_cirle(x + 0, y, cx, cy, r, rr) { 0xffff } else { 0 } << 16) |
-                             if sample_cirle(x + 1, y, cx, cy, r, rr) { 0xffff } else { 0 };
-                idx += 1;
+        render_image(&mut lcd, |x,y| {
+            if sample_cirle(x as i32, y as i32, cx, cy, r, rr) {
+                0xffff
+            } else {
+                0
             }
-        }
-
-        lcd.draw_picture(0, 0, DISP_WIDTH as u16, DISP_HEIGHT as u16, &image);
+        });
         // usleep(10000);
     }
 }
diff --git a/rust/game-of-life/.cargo/config b/rust/game-of-life/.cargo/config
deleted file mode 100644
index ab84f4b..0000000
--- a/rust/game-of-life/.cargo/config
+++ /dev/null
@@ -1,9 +0,0 @@
-[target.riscv64gc-unknown-none-elf]
-runner = "riscv64-unknown-elf-gdb -x gdb_init"
-rustflags = [
-  "-C", "link-arg=-Tmemory.x",
-  "-C", "link-arg=-Tlink.x",
-]
-
-[build]
-target = "riscv64gc-unknown-none-elf"
diff --git a/rust/game-of-life/gdb_init b/rust/game-of-life/gdb_init
deleted file mode 100644
index e7d61f4..0000000
--- a/rust/game-of-life/gdb_init
+++ /dev/null
@@ -1,3 +0,0 @@
-target remote :3333
-load
-c
diff --git a/rust/game-of-life/openocd.cfg b/rust/game-of-life/openocd.cfg
deleted file mode 100644
index 912647f..0000000
--- a/rust/game-of-life/openocd.cfg
+++ /dev/null
@@ -1,11 +0,0 @@
-transport select jtag
-adapter_khz 1000
-
-set _CHIPNAME riscv
-jtag newtap $_CHIPNAME cpu -irlen 5 -expected-id 0x04e4796b
-
-set _TARGETNAME $_CHIPNAME.cpu
-target create $_TARGETNAME riscv -chain-position $_TARGETNAME
-
-init
-halt
diff --git a/rust/game-of-life/src/main.rs b/rust/game-of-life/src/main.rs
index dc8adcc..bdbca97 100644
--- a/rust/game-of-life/src/main.rs
+++ b/rust/game-of-life/src/main.rs
@@ -8,7 +8,7 @@ use k210_hal::pac;
 use k210_hal::prelude::*;
 use k210_hal::stdout::Stdout;
 use k210_shared::board::def::{io,DISP_WIDTH,DISP_HEIGHT,NS2009_SLV_ADDR,NS2009_CAL,NS2009_ADDR_BITS,NS2009_CLK};
-use k210_shared::board::lcd::{LCD,self};
+use k210_shared::board::lcd::{LCD,LCDHL,self};
 use k210_shared::board::lcd_colors;
 use k210_shared::board::ns2009::TouchScreen;
 use k210_shared::soc::fpioa;
diff --git a/rust/accelerometer/gdb_init b/rust/gdb_init
similarity index 100%
rename from rust/accelerometer/gdb_init
rename to rust/gdb_init
diff --git a/rust/k210-console/.cargo/config b/rust/k210-console/.cargo/config
deleted file mode 100644
index ab84f4b..0000000
--- a/rust/k210-console/.cargo/config
+++ /dev/null
@@ -1,9 +0,0 @@
-[target.riscv64gc-unknown-none-elf]
-runner = "riscv64-unknown-elf-gdb -x gdb_init"
-rustflags = [
-  "-C", "link-arg=-Tmemory.x",
-  "-C", "link-arg=-Tlink.x",
-]
-
-[build]
-target = "riscv64gc-unknown-none-elf"
diff --git a/rust/k210-console/gdb_init b/rust/k210-console/gdb_init
deleted file mode 100644
index e7d61f4..0000000
--- a/rust/k210-console/gdb_init
+++ /dev/null
@@ -1,3 +0,0 @@
-target remote :3333
-load
-c
diff --git a/rust/k210-console/openocd.cfg b/rust/k210-console/openocd.cfg
deleted file mode 100644
index 912647f..0000000
--- a/rust/k210-console/openocd.cfg
+++ /dev/null
@@ -1,11 +0,0 @@
-transport select jtag
-adapter_khz 1000
-
-set _CHIPNAME riscv
-jtag newtap $_CHIPNAME cpu -irlen 5 -expected-id 0x04e4796b
-
-set _TARGETNAME $_CHIPNAME.cpu
-target create $_TARGETNAME riscv -chain-position $_TARGETNAME
-
-init
-halt
diff --git a/rust/k210-console/src/main.rs b/rust/k210-console/src/main.rs
index bb5857f..0a1a8e1 100644
--- a/rust/k210-console/src/main.rs
+++ b/rust/k210-console/src/main.rs
@@ -14,7 +14,7 @@ use k210_hal::pac;
 use k210_hal::prelude::*;
 use k210_hal::stdout::Stdout;
 use k210_shared::board::def::io;
-use k210_shared::board::lcd::{LCD,self};
+use k210_shared::board::lcd::{LCD,LCDHL,self};
 use k210_shared::board::lcd_colors;
 use k210_shared::soc::fpioa;
 use k210_shared::soc::sleep::usleep;
diff --git a/rust/k210-shared/Cargo.toml b/rust/k210-shared/Cargo.toml
index 8d75bc0..5b404f5 100644
--- a/rust/k210-shared/Cargo.toml
+++ b/rust/k210-shared/Cargo.toml
@@ -5,6 +5,7 @@ authors = ["W.J. van der Laan <laanwj@protonmail.com>"]
 edition = "2018"
 
 [dependencies]
-riscv-rt = "0.5.0"
 k210-hal = "0.1.0"
+libm = "0.1"
 riscv = "0.5"
+riscv-rt = "0.5.0"
diff --git a/rust/k210-shared/src/board.rs b/rust/k210-shared/src/board.rs
index 7eb3664..7fbc030 100644
--- a/rust/k210-shared/src/board.rs
+++ b/rust/k210-shared/src/board.rs
@@ -1,5 +1,6 @@
 pub mod def;
 pub mod lcd;
 pub mod lcd_colors;
+pub mod lcd_render;
 pub mod msa300;
 pub mod ns2009;
diff --git a/rust/k210-shared/src/board/lcd.rs b/rust/k210-shared/src/board/lcd.rs
index 9551105..11c6516 100644
--- a/rust/k210-shared/src/board/lcd.rs
+++ b/rust/k210-shared/src/board/lcd.rs
@@ -117,6 +117,25 @@ pub struct LCD<SPI> {
     pub height: u16,
 }
 
+/** Low-level interface */
+pub trait LCDLL {
+    fn hard_init(&self);
+    fn write_command(&self, cmd: command);
+    fn write_byte(&self, data_buf: &[u8]);
+    fn write_half(&self, data_buf: &[u16]);
+    fn write_word(&self, data_buf: &[u32]);
+    fn fill_data(&self, data: u32, length: usize);
+}
+
+/** High-level interface */
+pub trait LCDHL {
+    fn init(&mut self);
+    fn set_direction(&mut self, dir: direction);
+    fn set_area(&self, x1: u16, y1: u16, x2: u16, y2: u16);
+    fn clear(&self, color: u16);
+    fn draw_picture(&self, x1: u16, y1: u16, width: u16, height: u16, data: &[u32]);
+}
+
 impl<X: SPI> LCD<X> {
     pub fn new(spi: X) -> Self {
         Self {
@@ -126,8 +145,6 @@ impl<X: SPI> LCD<X> {
         }
     }
 
-    /* Low-level functions */
-
     fn init_dcx(&self) {
         gpiohs::set_direction(DCX_GPIONUM, gpio::direction::OUTPUT);
         gpiohs::set_pin(DCX_GPIONUM, true);
@@ -149,8 +166,11 @@ impl<X: SPI> LCD<X> {
     fn set_rst(&self, val: bool) {
         gpiohs::set_pin(RST_GPIONUM, val);
     }
+}
 
-    pub fn hard_init(&self) {
+/** Low-level functions */
+impl<X: SPI> LCDLL for LCD<X> {
+    fn hard_init(&self) {
         self.init_dcx();
         self.init_rst();
         self.set_rst(false);
@@ -169,7 +189,7 @@ impl<X: SPI> LCD<X> {
         self.set_rst(true);
     }
 
-    pub fn write_command(&self, cmd: command) {
+    fn write_command(&self, cmd: command) {
         self.set_dcx_control();
         self.spi.configure(
             ctrlr0::WORK_MODEW::MODE0,
@@ -185,7 +205,7 @@ impl<X: SPI> LCD<X> {
         self.spi.send_data(SPI_SLAVE_SELECT, &[cmd as u8]);
     }
 
-    pub fn write_byte(&self, data_buf: &[u8]) {
+    fn write_byte(&self, data_buf: &[u8]) {
         self.set_dcx_data();
         self.spi.configure(
             ctrlr0::WORK_MODEW::MODE0,
@@ -201,7 +221,7 @@ impl<X: SPI> LCD<X> {
         self.spi.send_data(SPI_SLAVE_SELECT, data_buf);
     }
 
-    pub fn write_half(&self, data_buf: &[u16]) {
+    fn write_half(&self, data_buf: &[u16]) {
         self.set_dcx_data();
         self.spi.configure(
             ctrlr0::WORK_MODEW::MODE0,
@@ -217,7 +237,7 @@ impl<X: SPI> LCD<X> {
         self.spi.send_data(SPI_SLAVE_SELECT, data_buf);
     }
 
-    pub fn write_word(&self, data_buf: &[u32]) {
+    fn write_word(&self, data_buf: &[u32]) {
         self.set_dcx_data();
         self.spi.configure(
             ctrlr0::WORK_MODEW::MODE0,
@@ -233,7 +253,7 @@ impl<X: SPI> LCD<X> {
         self.spi.send_data(SPI_SLAVE_SELECT, data_buf);
     }
 
-    pub fn fill_data(&self, data: u32, length: usize) {
+    fn fill_data(&self, data: u32, length: usize) {
         self.set_dcx_data();
         self.spi.configure(
             ctrlr0::WORK_MODEW::MODE0,
@@ -248,10 +268,11 @@ impl<X: SPI> LCD<X> {
         );
         self.spi.fill_data(SPI_SLAVE_SELECT, data, length);
     }
+}
 
-    /* High-level functions */
-
-    pub fn init(&mut self) {
+/* High-level functions */
+impl<X: SPI> LCDHL for LCD<X> {
+    fn init(&mut self) {
         self.hard_init();
         /*soft reset*/
         self.write_command(command::SOFTWARE_RESET);
@@ -268,7 +289,7 @@ impl<X: SPI> LCD<X> {
         self.write_command(command::DISPLAY_ON);
     }
 
-    pub fn set_direction(&mut self, dir: direction) {
+    fn set_direction(&mut self, dir: direction) {
         if ((dir as u8) & DIR_XY_MASK) != 0 {
             self.width = LCD_Y_MAX;
             self.height = LCD_X_MAX;
@@ -281,7 +302,7 @@ impl<X: SPI> LCD<X> {
         self.write_byte(&[dir as u8]);
     }
 
-    pub fn set_area(&self, x1: u16, y1: u16, x2: u16, y2: u16) {
+    fn set_area(&self, x1: u16, y1: u16, x2: u16, y2: u16) {
         self.write_command(command::HORIZONTAL_ADDRESS_SET);
         self.write_byte(&[
             (x1 >> 8) as u8,
@@ -301,14 +322,14 @@ impl<X: SPI> LCD<X> {
         self.write_command(command::MEMORY_WRITE);
     }
 
-    pub fn clear(&self, color: u16) {
+    fn clear(&self, color: u16) {
         let data = ((color as u32) << 16) | (color as u32);
 
         self.set_area(0, 0, self.width - 1, self.height - 1);
         self.fill_data(data, (LCD_X_MAX as usize) * (LCD_Y_MAX as usize) / 2);
     }
 
-    pub fn draw_picture(&self, x1: u16, y1: u16, width: u16, height: u16, data: &[u32]) {
+    fn draw_picture(&self, x1: u16, y1: u16, width: u16, height: u16, data: &[u32]) {
         self.set_area(x1, y1, x1 + width - 1, y1 + height - 1);
         assert!(data.len() == (width as usize) * (height as usize) / 2);
         self.write_word(data);
diff --git a/rust/k210-shared/src/board/lcd_colors.rs b/rust/k210-shared/src/board/lcd_colors.rs
index d5c592d..f0eedf8 100644
--- a/rust/k210-shared/src/board/lcd_colors.rs
+++ b/rust/k210-shared/src/board/lcd_colors.rs
@@ -1,3 +1,5 @@
+use libm::F32Ext;
+
 /** Some convenient RGB565 colors */
 pub const BLACK: u16 = 0x0000;
 pub const NAVY: u16 = 0x000F;
@@ -21,5 +23,55 @@ pub const PINK: u16 = 0xF81F;
 
 /** Truncate 8 bit RGB to RBG565 */
 pub const fn rgb565(r: u8, g: u8, b: u8) -> u16 {
-    return (((r as u16) >> 3) << 11) | (((g as u16) >> 2) << 5) | ((b as u16) >> 3);
+    (((r as u16) >> 3) << 11) | (((g as u16) >> 2) << 5) | ((b as u16) >> 3)
+}
+
+/** 32.0 minus 1ulp */
+const ALMOST_32: f32 = 31.999998f32;
+/** 64.0 minus 1ulp */
+const ALMOST_64: f32 = 63.999996f32;
+
+/** Truncate 32 bit RGB to RBG565 */
+pub fn rgbf565(r: f32, g: f32, b: f32) -> u16 {
+    (((r * ALMOST_32) as u16) << 11) |
+      (((g * ALMOST_64) as u16) << 5) |
+      ((b * ALMOST_32) as u16)
+}
+
+/** HSV to RGB. `h` is 0.0..360.0, `s` and `v` are 0.0..1.0 output RGB will be 0.0..1.0 (all ranges
+ * inclusive)
+ */
+pub fn hsv2rgb(h: f32, s: f32, v: f32) -> (f32, f32, f32) {
+    let h = h / 60.0;
+    let i = h.trunc();
+    let f = h - i;
+
+    let c = v * (1.0 - s * f);
+    let b = v * (1.0 - s + s * f);
+    let o = v * (1.0 - s);
+    match i as u32 {
+        // yellow to green
+        1 => (c, v, o),
+        // green to cyan
+        2 => (o, v, b),
+        // cyan to blue
+        3 => (o, c, v),
+        // blue to magenta
+        4 => (b, o, v),
+        // magenta to red
+        5 => (v, o, c),
+        // red to yellow
+        _ => (v, b, o),
+    }
+}
+
+/** Clamp a float between 0 and 1 */
+pub fn clampf(v: f32) -> f32 {
+    if v < 0.0 {
+        0.0
+    } else if v > 1.0 {
+        1.0
+    } else {
+        v
+    }
 }
diff --git a/rust/k210-shared/src/board/lcd_render.rs b/rust/k210-shared/src/board/lcd_render.rs
new file mode 100644
index 0000000..b573a12
--- /dev/null
+++ b/rust/k210-shared/src/board/lcd_render.rs
@@ -0,0 +1,33 @@
+/** Efficient(?) full-image rendering */
+use crate::board::def::{DISP_HEIGHT, DISP_WIDTH};
+use crate::board::lcd::LCDHL;
+
+/** Array for representing an image of the entire screen.
+ * This is an array of DISP_WIDTH / 2 × DISP_HEIGHT, each two horizontally consecutive
+ * pixels are encoded in a u32 with `(a << 16)|b`.
+ */
+pub type ScreenImage = [u32; DISP_WIDTH * DISP_HEIGHT / 2];
+
+pub fn render_image<L, I>(lcd: &mut L, mut image: I)
+where
+    L: LCDHL,
+    I: FnMut(u16, u16) -> u16,
+{
+    // Theoretically this initialization could be avoided by directly initializing from an
+    // iterator, however, rust doesn't have built-in functionality for this. There's a crate
+    // (array_init) but it doesn't work for large arrays.
+    let mut idata: ScreenImage = [0; DISP_WIDTH * DISP_HEIGHT / 2];
+    let yx = (0..DISP_HEIGHT)
+        .flat_map(|y| core::iter::repeat(y as u16).zip(0 as u16..(DISP_WIDTH / 2) as u16));
+    idata.iter_mut().zip(yx).for_each(|(v, (y, x))| {
+        *v = ((image(x * 2 + 0, y) as u32) << 16) | (image(x * 2 + 1, y) as u32);
+    });
+
+    // It would be possible to make draw_picture take an iterator directly
+    // instead of rendering to an array first, however, this means that the
+    // computation has to keep up with the SPI clock speed or there will be
+    // glitches -- also it means that DMA cannot be used -- whereas a sufficiently
+    // advanced DMA engine is indistinguishable from a GPU, the one in K210
+    // isn't that.
+    lcd.draw_picture(0, 0, DISP_WIDTH as u16, DISP_HEIGHT as u16, &idata);
+}
diff --git a/rust/k210-shared/src/soc.rs b/rust/k210-shared/src/soc.rs
index d52d13b..504496b 100644
--- a/rust/k210-shared/src/soc.rs
+++ b/rust/k210-shared/src/soc.rs
@@ -2,6 +2,7 @@ pub mod fpioa;
 pub mod gpio;
 pub mod gpiohs;
 pub mod i2c;
+pub mod pwm;
 pub mod sleep;
 pub mod spi;
 pub mod sysctl;
diff --git a/rust/k210-shared/src/soc/pwm.rs b/rust/k210-shared/src/soc/pwm.rs
new file mode 100644
index 0000000..f284abb
--- /dev/null
+++ b/rust/k210-shared/src/soc/pwm.rs
@@ -0,0 +1,56 @@
+use k210_hal::pac;
+// TODO: generalize over other timers than TIMER0
+// use pac::{timer0,TIMER0,TIMER1,TIMER2};
+
+use crate::soc::sysctl;
+
+#[derive(Copy, Clone, PartialEq, Eq)]
+pub enum Channel {
+    CH1 = 0,
+    CH2,
+    CH3,
+    CH4,
+}
+
+/** Start a PWM channel */
+pub fn pwm_start(ch: Channel) {
+    unsafe {
+        let ptr = pac::TIMER0::ptr();
+        use pac::timer0::channel::control::MODEW;
+
+        // set a deterministic value for load counts
+        (*ptr).channel[ch as usize].load_count.write(|w| w.bits(1));
+        (*ptr).load_count2[ch as usize].write(|w| w.bits(1));
+        // start channel
+        (*ptr).channel[ch as usize].control.write(
+            |w| w.interrupt().set_bit()
+                 .pwm_enable().set_bit()
+                 .mode().variant(MODEW::USER)
+                 .enable().set_bit());
+    }
+}
+
+/** Stop a PWM channel */
+pub fn pwm_stop(ch: Channel) {
+    unsafe {
+        let ptr = pac::TIMER0::ptr();
+
+        (*ptr).channel[ch as usize].control.write(
+            |w| w.interrupt().set_bit());
+    }
+}
+
+/** Set frequency and value for a PWM channel */
+pub fn pwm_set(ch: Channel, freq: u32, value: f32) -> u32 {
+    let clk_freq = sysctl::clock_get_freq(sysctl::clock::TIMER0);
+    let periods = clk_freq / freq;
+    let percent = (value * (periods as f32)) as u32;
+    unsafe {
+        let ptr = pac::TIMER0::ptr();
+        (*ptr).channel[ch as usize].load_count.write(|w| w.bits(periods - percent));
+        (*ptr).load_count2[ch as usize].write(|w| w.bits(percent));
+    }
+    clk_freq / periods
+}
+
+
diff --git a/rust/mandelbrot/.cargo/config b/rust/mandelbrot/.cargo/config
deleted file mode 100644
index ab84f4b..0000000
--- a/rust/mandelbrot/.cargo/config
+++ /dev/null
@@ -1,9 +0,0 @@
-[target.riscv64gc-unknown-none-elf]
-runner = "riscv64-unknown-elf-gdb -x gdb_init"
-rustflags = [
-  "-C", "link-arg=-Tmemory.x",
-  "-C", "link-arg=-Tlink.x",
-]
-
-[build]
-target = "riscv64gc-unknown-none-elf"
diff --git a/rust/mandelbrot/gdb_init b/rust/mandelbrot/gdb_init
deleted file mode 100644
index e7d61f4..0000000
--- a/rust/mandelbrot/gdb_init
+++ /dev/null
@@ -1,3 +0,0 @@
-target remote :3333
-load
-c
diff --git a/rust/mandelbrot/openocd.cfg b/rust/mandelbrot/openocd.cfg
deleted file mode 100644
index 912647f..0000000
--- a/rust/mandelbrot/openocd.cfg
+++ /dev/null
@@ -1,11 +0,0 @@
-transport select jtag
-adapter_khz 1000
-
-set _CHIPNAME riscv
-jtag newtap $_CHIPNAME cpu -irlen 5 -expected-id 0x04e4796b
-
-set _TARGETNAME $_CHIPNAME.cpu
-target create $_TARGETNAME riscv -chain-position $_TARGETNAME
-
-init
-halt
diff --git a/rust/mandelbrot/src/main.rs b/rust/mandelbrot/src/main.rs
index 239b51d..3060d31 100644
--- a/rust/mandelbrot/src/main.rs
+++ b/rust/mandelbrot/src/main.rs
@@ -10,8 +10,9 @@ use k210_hal::pac;
 use k210_hal::prelude::*;
 use k210_hal::stdout::Stdout;
 use k210_shared::board::def::{io,DISP_WIDTH,DISP_HEIGHT};
-use k210_shared::board::lcd::{LCD,self};
+use k210_shared::board::lcd::{LCD,LCDHL,self};
 use k210_shared::board::lcd_colors;
+use k210_shared::board::lcd_render::render_image;
 use k210_shared::soc::fpioa;
 use k210_shared::soc::sleep::usleep;
 use k210_shared::soc::spi::SPIExt;
@@ -20,8 +21,6 @@ use riscv_rt::entry;
 
 use crate::palette::PALETTE;
 
-pub type ScreenImage = [u32; DISP_WIDTH * DISP_HEIGHT / 2];
-
 /** Connect pins to internal functions */
 fn io_mux_init() {
     /* Init SPI IO map and function settings */
@@ -52,16 +51,6 @@ fn mandelbrot(cx: f32, cy: f32, iterations: u32) -> u32 {
     i
 }
 
-fn compute(x: u16, y: u16, zoom: f32) -> u16 {
-    let ofsx = 0.02997f32;
-    let ofsy = 0.80386f32;
-    let xx = 2.0 * (x as f32) / ((DISP_WIDTH-1) as f32) - 1.0;
-    let yy = 2.0 * (y as f32) / ((DISP_HEIGHT-1) as f32) - 1.0;
-    let i = mandelbrot(xx * zoom + ofsx, yy * zoom + ofsy, 20);
-
-    PALETTE[i as usize]
-}
-
 #[entry]
 fn main() -> ! {
     let p = pac::Peripherals::take().unwrap();
@@ -86,22 +75,19 @@ fn main() -> ! {
     lcd.set_direction(lcd::direction::YX_RLDU);
     lcd.clear(lcd_colors::PURPLE);
 
-    let mut image: ScreenImage = [0; DISP_WIDTH * DISP_HEIGHT / 2];
-
     writeln!(stdout, "First frame").unwrap();
-    let mut frame = 0;
     let mut zoom = 5.0f32;
+    let ofsx = 0.02997f32;
+    let ofsy = 0.80386f32;
     loop {
-        let mut ofs = 0;
-        for y in 0..DISP_HEIGHT as u16 {
-            for x in 0..(DISP_WIDTH/2) as u16 {
-                image[ofs] = ((compute(x*2+0, y, zoom) as u32)<<16) | (compute(x*2+1, y, zoom) as u32);
-                ofs += 1;
-            }
-        }
-        lcd.draw_picture(0, 0, DISP_WIDTH as u16, DISP_HEIGHT as u16, &image);
+        render_image(&mut lcd, |x,y| {
+            let xx = 2.0 * (x as f32) / ((DISP_WIDTH-1) as f32) - 1.0;
+            let yy = 2.0 * (y as f32) / ((DISP_HEIGHT-1) as f32) - 1.0;
+            let i = mandelbrot(xx * zoom + ofsx, yy * zoom + ofsy, 20);
+
+            PALETTE[i as usize]
+        });
 
-        frame += 1;
         zoom *= 0.98f32;
     }
 }
diff --git a/rust/accelerometer/openocd.cfg b/rust/openocd.cfg
similarity index 100%
rename from rust/accelerometer/openocd.cfg
rename to rust/openocd.cfg
diff --git a/rust/rgbcontrol/.gitignore b/rust/rgbcontrol/.gitignore
new file mode 100644
index 0000000..f0e3bca
--- /dev/null
+++ b/rust/rgbcontrol/.gitignore
@@ -0,0 +1,2 @@
+/target
+**/*.rs.bk
\ No newline at end of file
diff --git a/rust/rgbcontrol/Cargo.toml b/rust/rgbcontrol/Cargo.toml
new file mode 100644
index 0000000..4ba0915
--- /dev/null
+++ b/rust/rgbcontrol/Cargo.toml
@@ -0,0 +1,11 @@
+[package]
+name = "rgbcontrol"
+version = "0.1.0"
+authors = ["W.J. van der Laan <laanwj@protonmail.com>"]
+edition = "2018"
+
+[dependencies]
+k210-hal = "0.1.0"
+k210-shared = { path = "../k210-shared" }
+riscv = "0.5"
+riscv-rt = "0.5.0"
diff --git a/rust/rgbcontrol/README.md b/rust/rgbcontrol/README.md
new file mode 100644
index 0000000..c5d4cb0
--- /dev/null
+++ b/rust/rgbcontrol/README.md
@@ -0,0 +1,10 @@
+# `rgbcontrol`
+
+Control the color of the RGB LED from the touch screen.
+
+Displays a HSV color picker and sets sets the color of the LED based on the
+position that is touched, with the intensity derived from the touch pressure.
+
+Exercises the PWM functionality. Channel 1-3 of TIMER0 are assigned to the
+R, G and B pins.
+
diff --git a/rust/rgbcontrol/src/main.rs b/rust/rgbcontrol/src/main.rs
new file mode 100644
index 0000000..1c30280
--- /dev/null
+++ b/rust/rgbcontrol/src/main.rs
@@ -0,0 +1,128 @@
+#![allow(dead_code)]
+#![allow(non_snake_case)]
+#![allow(non_camel_case_types)]
+#![no_std]
+#![no_main]
+
+use k210_hal::pac;
+use k210_hal::prelude::*;
+use k210_hal::stdout::Stdout;
+use k210_shared::board::def::{
+    io, DISP_HEIGHT, DISP_WIDTH, NS2009_ADDR_BITS, NS2009_CAL, NS2009_CLK, NS2009_SLV_ADDR,
+};
+use k210_shared::board::lcd::{self, LCD, LCDHL};
+use k210_shared::board::lcd_colors::{clampf, hsv2rgb, rgbf565};
+use k210_shared::board::lcd_render::render_image;
+use k210_shared::board::ns2009::TouchScreen;
+use k210_shared::soc::fpioa;
+use k210_shared::soc::i2c::{I2CExt, I2C};
+use k210_shared::soc::pwm::{pwm_set, pwm_start, Channel};
+use k210_shared::soc::sleep::usleep;
+use k210_shared::soc::spi::SPIExt;
+use k210_shared::soc::sysctl;
+use riscv_rt::entry;
+
+// Factor for equalizing relative brightness of R/G/B leds
+const R_SCALE: f32 = 1.0;
+const G_SCALE: f32 = 0.16;
+const B_SCALE: f32 = 0.33;
+
+fn io_init() {
+    /* Init SPI IO map and function settings */
+    fpioa::set_function(
+        io::LCD_RST.into(),
+        fpioa::function::gpiohs(lcd::RST_GPIONUM),
+    );
+    fpioa::set_io_pull(io::LCD_RST.into(), fpioa::pull::DOWN); // outputs must be pull-down
+    fpioa::set_function(io::LCD_DC.into(), fpioa::function::gpiohs(lcd::DCX_GPIONUM));
+    fpioa::set_io_pull(io::LCD_DC.into(), fpioa::pull::DOWN);
+    fpioa::set_function(io::LCD_CS.into(), fpioa::function::SPI0_SS3);
+    fpioa::set_function(io::LCD_WR.into(), fpioa::function::SPI0_SCLK);
+
+    /* Route PWM outputs of TIMER0 to RGB leds */
+    fpioa::set_function(io::LED_R as u8, fpioa::function::TIMER0_TOGGLE1);
+    fpioa::set_function(io::LED_G as u8, fpioa::function::TIMER0_TOGGLE2);
+    fpioa::set_function(io::LED_B as u8, fpioa::function::TIMER0_TOGGLE3);
+
+    sysctl::set_spi0_dvp_data(true);
+
+    /* I2C0 for touch-screen */
+    fpioa::set_function(io::I2C1_SCL.into(), fpioa::function::I2C0_SCLK);
+    fpioa::set_function(io::I2C1_SDA.into(), fpioa::function::I2C0_SDA);
+
+    /* Set DVP and SPI pins to 1.8V */
+    sysctl::set_power_mode(sysctl::power_bank::BANK6, sysctl::io_power_mode::V18);
+    sysctl::set_power_mode(sysctl::power_bank::BANK7, sysctl::io_power_mode::V18);
+}
+
+/** Color picker */
+fn color_from_xy(x: u16, y: u16, v: f32) -> (f32, f32, f32) {
+    hsv2rgb(
+        360.0 * (x as f32) / (DISP_WIDTH as f32),
+        (y as f32) / ((DISP_HEIGHT - 1) as f32),
+        v,
+    )
+}
+
+#[entry]
+fn main() -> ! {
+    let p = pac::Peripherals::take().unwrap();
+    let clocks = k210_hal::clock::Clocks::new();
+
+    usleep(200000);
+
+    let serial = p.UARTHS.constrain(115_200.bps(), &clocks);
+    let (mut tx, _) = serial.split();
+    let mut stdout = Stdout(&mut tx);
+
+    io_init();
+
+    writeln!(stdout, "NS2009 init").unwrap();
+    let i2c = p.I2C0.constrain();
+    i2c.init(NS2009_SLV_ADDR, NS2009_ADDR_BITS, NS2009_CLK);
+    let mut ts = if let Some(ts) = TouchScreen::init(i2c, NS2009_CAL) {
+        ts
+    } else {
+        writeln!(stdout, "NS2009 init failure").unwrap();
+        panic!("Fatal error");
+    };
+
+    writeln!(stdout, "LCD init").unwrap();
+    let spi = p.SPI0.constrain();
+    let mut lcd = LCD::new(spi);
+    lcd.init();
+    lcd.set_direction(lcd::direction::YX_LRUD);
+    render_image(&mut lcd, |x, y| {
+        let (r, g, b) = color_from_xy(x, y, 1.0);
+        rgbf565(r, g, b)
+    });
+
+    writeln!(stdout, "start PWM").unwrap();
+    sysctl::clock_enable(sysctl::clock::TIMER0);
+    pwm_start(Channel::CH1);
+    pwm_start(Channel::CH2);
+    pwm_start(Channel::CH3);
+
+    let freq = 10000;
+
+    loop {
+        if let Some(ev) = ts.poll() {
+            if ev.z > 0
+                && ev.x >= 0
+                && ev.x < (DISP_WIDTH as i32)
+                && ev.y >= 0
+                && ev.y < (DISP_HEIGHT as i32)
+            {
+                //writeln!(stdout, "{:?}", ev).unwrap();
+                let (r, g, b) =
+                    color_from_xy(ev.x as u16, ev.y as u16, clampf(ev.z as f32 / 1000.0));
+
+                pwm_set(Channel::CH1, freq, 1.0 - r * R_SCALE);
+                pwm_set(Channel::CH2, freq, 1.0 - g * G_SCALE);
+                pwm_set(Channel::CH3, freq, 1.0 - b * B_SCALE);
+            }
+        }
+
+        usleep(10000);
+    }
+}
diff --git a/rust/uart-passthrough/.cargo/config b/rust/uart-passthrough/.cargo/config
deleted file mode 100644
index 8bcf92f..0000000
--- a/rust/uart-passthrough/.cargo/config
+++ /dev/null
@@ -1,8 +0,0 @@
-[target.riscv64gc-unknown-none-elf]
-rustflags = [
-  "-C", "link-arg=-Tmemory.x",
-  "-C", "link-arg=-Tlink.x",
-]
-
-[build]
-target = "riscv64gc-unknown-none-elf"