Support for YMDK NP21 (#2316)

* ymdk_np21 initial support

Base support of ymdk_np21 - based on jj40. Full grid layout

* Update README.md

Replacing description.

* Adding YMDK NP21 to comunity list.

Adding YMDK NP21 to community supported list.

14 files changed, 1312 insertions, 0 deletions

diff --git a/keyboards/readme.md b/keyboards/readme.md
index b81d5841ee..35900f611f 100644
--- a/keyboards/readme.md
+++ b/keyboards/readme.md
@@ -60,3 +60,4 @@ These keyboards are part of the QMK repository, but their manufacturers are not
 * [WhiteFox](/keyboards/whitefox) — A 65% keyboard designed as a partnership by matt3o, Massdrop and Input Club
 * [Vision Division](/keyboards/vision_division) — Full Size / Split Linear Keyboard by IBNobody.
 * [XD75](/keyboards/xd75) — 15x5 ortholinear keyboard by XIUDI.
+* [YMDK NP21](/keyboards/ymdk_np21) — ps2avrGB based number pad (numpad) sold by YMDK on Aliexpress. 
diff --git a/keyboards/ymdk_np21/README.md b/keyboards/ymdk_np21/README.md
new file mode 100644
index 0000000000..79e3386f09
--- /dev/null
+++ b/keyboards/ymdk_np21/README.md
@@ -0,0 +1,17 @@
+# YMDK NP21
+
+![kp21 — full grid layout](https://ae01.alicdn.com/kf/HTB1d.txfHsTMeJjSszhq6AGCFXaF.jpg?size=35021&height=662&width=1000&hash=62b3a453686e2154dc51a7af67495e28)
+
+ps2avrGB based number-pad sold fully assembled by YMDK on Aliexpress.
+
+Keyboard Maintainer: [QMK Community](https://github.com/qmk)  
+Hardware Supported: Atmega32A
+Hardware Availability: [AliExpress](https://www.aliexpress.com/item/21-Key-NPKC-Programmable-Cherry-MX-Kailh-Gateron-Switches-Mechanical-Keyboard-Numpad-Free-shipping/32812732361.html)
+
+Make example for this keyboard (after setting up your build environment):
+
+    make ymdk_np21:default:program
+
+Plugging the board in while pressing 'Top Left Key' (USB on top) will force it to boot bootloader without loading the firmware.
+
+The code for NP21 is a minor edit of jj40.
diff --git a/keyboards/ymdk_np21/backlight.c b/keyboards/ymdk_np21/backlight.c
new file mode 100644
index 0000000000..079c410ff5
--- /dev/null
+++ b/keyboards/ymdk_np21/backlight.c
@@ -0,0 +1,212 @@
+/**
+ * Backlighting code for PS2AVRGB boards (ATMEGA32A)
+ * Kenneth A. (github.com/krusli | krusli.me)
+ */
+
+#include "backlight.h"
+#include "quantum.h"
+
+#include <avr/pgmspace.h>
+#include <avr/interrupt.h>
+
+#include "backlight_custom.h"
+#include "breathing_custom.h"
+
+// DEBUG
+#include <stdlib.h>
+#include <stdio.h>
+
+// Port D: digital pins of the AVR chipset
+#define NUMLOCK_PORT    (1 << 1)  // 1st pin of Port D (digital)
+#define CAPSLOCK_PORT   (1 << 2)  // 2nd pin
+#define BACKLIGHT_PORT  (1 << 4)  // 4th pin
+#define SCROLLLOCK_PORT (1 << 6)  // 6th pin
+
+#define TIMER_CLK_DIV64			  0x03	///< Timer clocked at F_CPU/64
+#define TIMER1PRESCALE	TIMER_CLK_DIV64 ///< timer 1 prescaler default
+
+#define TIMER_PRESCALE_MASK		0x07	///< Timer Prescaler Bit-Mask
+
+#define PWM_MAX 0xFF
+#define TIMER_TOP 255 // 8 bit PWM
+
+extern backlight_config_t backlight_config;
+
+/**
+ * References
+ * Port Registers: https://www.arduino.cc/en/Reference/PortManipulation
+ * TCCR1A: https://electronics.stackexchange.com/questions/92350/what-is-the-difference-between-tccr1a-and-tccr1b
+ * Timers: http://www.avrbeginners.net/architecture/timers/timers.html
+ * 16-bit timer setup: http://sculland.com/ATmega168/Interrupts-And-Timers/16-Bit-Timer-Setup/
+ * PS2AVRGB firmware: https://github.com/showjean/ps2avrU/tree/master/firmware
+ */
+
+// @Override
+// turn LEDs on and off depending on USB caps/num/scroll lock states.
+void led_set_user(uint8_t usb_led) {
+    if (usb_led & (1 << USB_LED_NUM_LOCK)) {
+      // turn on
+      DDRD  |= NUMLOCK_PORT;
+      PORTD |= NUMLOCK_PORT;
+    } else {
+      // turn off
+      DDRD  &= ~NUMLOCK_PORT;
+      PORTD &= ~NUMLOCK_PORT;
+    }
+
+    if (usb_led & (1 << USB_LED_CAPS_LOCK)) {
+      DDRD  |= CAPSLOCK_PORT;
+      PORTD |= CAPSLOCK_PORT;
+    } else {
+      DDRD  &= ~CAPSLOCK_PORT;
+      PORTD &= ~CAPSLOCK_PORT;
+    }
+
+    if (usb_led & (1 << USB_LED_SCROLL_LOCK)) {
+      DDRD  |= SCROLLLOCK_PORT;
+      PORTD |= SCROLLLOCK_PORT;
+    } else {
+      DDRD  &= ~SCROLLLOCK_PORT;
+      PORTD &= ~SCROLLLOCK_PORT;
+    }
+}
+
+#ifdef BACKLIGHT_ENABLE
+
+// sets up Timer 1 for 8-bit PWM
+void timer1PWMSetup(void) { // NOTE ONLY CALL THIS ONCE
+  // default 8 bit mode
+  TCCR1A &= ~(1 << 1); // cbi(TCCR1A,PWM11); <- set PWM11 bit to HIGH
+  TCCR1A |= (1 << 0);  // sbi(TCCR1A,PWM10); <- set PWM10 bit to LOW
+
+  // clear output compare value A
+  // outb(OCR1AH, 0);
+  // outb(OCR1AL, 0);
+
+  // clear output comparator registers for B
+	OCR1BH = 0; // outb(OCR1BH, 0);
+	OCR1BL = 0; // outb(OCR1BL, 0);
+}
+
+bool is_init = false;
+void timer1Init(void) {
+  // timer1SetPrescaler(TIMER1PRESCALE)
+  // set to DIV/64
+  (TCCR1B) = ((TCCR1B) & ~TIMER_PRESCALE_MASK) | TIMER1PRESCALE;
+
+  // reset TCNT1
+  TCNT1H = 0;  // outb(TCNT1H, 0);
+	TCNT1L = 0;  // outb(TCNT1L, 0);
+
+  // TOIE1: Timer Overflow Interrupt Enable (Timer 1);
+	TIMSK |= _BV(TOIE1); // sbi(TIMSK, TOIE1);
+
+  is_init = true;
+}
+
+void timer1UnInit(void) {
+  // set prescaler back to NONE
+  (TCCR1B) = ((TCCR1B) & ~TIMER_PRESCALE_MASK) | 0x00;  // TIMERRTC_CLK_STOP
+
+  // disable timer overflow interrupt
+  TIMSK &= ~_BV(TOIE1); // overflow bit?
+
+  setPWM(0);
+
+  is_init = false;
+}
+
+
+// handle TCNT1 overflow
+//! Interrupt handler for tcnt1 overflow interrupt
+ISR(TIMER1_OVF_vect, ISR_NOBLOCK)
+{
+	// sei();
+  // handle breathing here
+  #ifdef BACKLIGHT_BREATHING
+  if (is_breathing()) {
+    custom_breathing_handler();
+  }
+  #endif
+
+  // TODO call user defined function
+}
+
+// enable timer 1 PWM
+// timer1PWMBOn()
+void timer1PWMBEnable(void) {
+  // turn on channel B (OC1B) PWM output
+  // set OC1B as non-inverted PWM
+  TCCR1A |= _BV(COM1B1);
+  TCCR1A &= ~_BV(COM1B0);
+}
+
+// disable timer 1 PWM
+// timer1PWMBOff()
+void timer1PWMBDisable(void) {
+  TCCR1A &= ~_BV(COM1B1);
+  TCCR1A &= ~_BV(COM1B0);
+}
+
+void enableBacklight(void) {
+  DDRD  |= BACKLIGHT_PORT;  // set digital pin 4 as output
+  PORTD |= BACKLIGHT_PORT;  // set digital pin 4 to high
+}
+
+void disableBacklight(void) {
+  // DDRD  &= ~BACKLIGHT_PORT;  // set digital pin 4 as input
+  PORTD &= ~BACKLIGHT_PORT;  // set digital pin 4 to low
+}
+
+void startPWM(void) {
+  timer1Init();
+  timer1PWMBEnable();
+  enableBacklight();
+}
+
+void stopPWM(void) {
+  timer1UnInit();
+  disableBacklight();
+  timer1PWMBDisable();
+}
+
+void b_led_init_ports(void) {
+  /* turn backlight on/off depending on user preference */
+  #if BACKLIGHT_ON_STATE == 0
+    // DDRx register: sets the direction of Port D
+    // DDRD  &= ~BACKLIGHT_PORT;  // set digital pin 4 as input
+    PORTD &= ~BACKLIGHT_PORT;  // set digital pin 4 to low
+  #else
+    DDRD  |= BACKLIGHT_PORT;  // set digital pin 4 as output
+    PORTD |= BACKLIGHT_PORT;  // set digital pin 4 to high
+  #endif
+
+  timer1PWMSetup();
+  startPWM();
+
+  #ifdef BACKLIGHT_BREATHING
+  breathing_enable();
+  #endif
+}
+
+void b_led_set(uint8_t level) {
+  if (level > BACKLIGHT_LEVELS) {
+    level = BACKLIGHT_LEVELS;
+  }
+
+  setPWM((int)(TIMER_TOP * (float) level / BACKLIGHT_LEVELS));
+}
+
+// called every matrix scan
+void b_led_task(void) {
+  // do nothing for now
+}
+
+void setPWM(uint16_t xValue) {
+  if (xValue > TIMER_TOP) {
+    xValue = TIMER_TOP;
+  }
+  OCR1B = xValue; // timer1PWMBSet(xValue);
+}
+
+#endif  // BACKLIGHT_ENABLE
diff --git a/keyboards/ymdk_np21/backlight_custom.h b/keyboards/ymdk_np21/backlight_custom.h
new file mode 100644
index 0000000000..7210be840e
--- /dev/null
+++ b/keyboards/ymdk_np21/backlight_custom.h
@@ -0,0 +1,15 @@
+/**
+ * Backlighting code for PS2AVRGB boards (ATMEGA32A)
+ * Kenneth A. (github.com/krusli | krusli.me)
+ */
+
+#ifndef BACKLIGHT_CUSTOM_H
+#define BACKLIGHT_CUSTOM_H
+
+#include <avr/pgmspace.h>
+void b_led_init_ports(void);
+void b_led_set(uint8_t level);
+void b_led_task(void);
+void setPWM(uint16_t xValue);
+
+#endif  // BACKLIGHT_CUSTOM_H
diff --git a/keyboards/ymdk_np21/breathing_custom.h b/keyboards/ymdk_np21/breathing_custom.h
new file mode 100644
index 0000000000..71416b1b45
--- /dev/null
+++ b/keyboards/ymdk_np21/breathing_custom.h
@@ -0,0 +1,140 @@
+/**
+ * Breathing effect code for PS2AVRGB boards (ATMEGA32A)
+ * Works in conjunction with `backlight.c`.
+ *
+ * Code adapted from `quantum.c` to register with the existing TIMER1 overflow
+ * handler in `backlight.c` instead of setting up its own timer.
+ * Kenneth A. (github.com/krusli | krusli.me)
+ */
+
+#ifdef BACKLIGHT_ENABLE
+#ifdef BACKLIGHT_BREATHING
+
+#include "backlight_custom.h"
+
+#ifndef BREATHING_PERIOD
+#define BREATHING_PERIOD 6
+#endif
+
+#define breathing_min() do {breathing_counter = 0;} while (0)
+#define breathing_max() do {breathing_counter = breathing_period * 244 / 2;} while (0)
+
+// TODO make this share code with quantum.c
+
+#define BREATHING_NO_HALT  0
+#define BREATHING_HALT_OFF 1
+#define BREATHING_HALT_ON  2
+#define BREATHING_STEPS 128
+
+static uint8_t breathing_period = BREATHING_PERIOD;
+static uint8_t breathing_halt = BREATHING_NO_HALT;
+static uint16_t breathing_counter = 0;
+
+static bool breathing = false;
+
+bool is_breathing(void) {
+  return breathing;
+}
+
+// See http://jared.geek.nz/2013/feb/linear-led-pwm
+static uint16_t cie_lightness(uint16_t v) {
+  if (v <= 5243) // if below 8% of max
+    return v / 9; // same as dividing by 900%
+  else {
+    uint32_t y = (((uint32_t) v + 10486) << 8) / (10486 + 0xFFFFUL); // add 16% of max and compare
+    // to get a useful result with integer division, we shift left in the expression above
+    // and revert what we've done again after squaring.
+    y = y * y * y >> 8;
+    if (y > 0xFFFFUL) // prevent overflow
+      return 0xFFFFU;
+    else
+      return (uint16_t) y;
+  }
+}
+
+void breathing_enable(void) {
+  breathing = true;
+  breathing_counter = 0;
+  breathing_halt = BREATHING_NO_HALT;
+  // interrupt already registered
+}
+
+void breathing_pulse(void) {
+  if (get_backlight_level() == 0)
+    breathing_min();
+  else
+    breathing_max();
+  breathing_halt = BREATHING_HALT_ON;
+  // breathing_interrupt_enable();
+  breathing = true;
+}
+
+void breathing_disable(void) {
+  breathing = false;
+  // backlight_set(get_backlight_level());
+  b_led_set(get_backlight_level()); // custom implementation of backlight_set()
+}
+
+void breathing_self_disable(void)
+{
+  if (get_backlight_level() == 0)
+    breathing_halt = BREATHING_HALT_OFF;
+  else
+    breathing_halt = BREATHING_HALT_ON;
+}
+
+void breathing_toggle(void) {
+  if (is_breathing())
+    breathing_disable();
+  else
+    breathing_enable();
+}
+
+void breathing_period_set(uint8_t value)
+{
+  if (!value)
+    value = 1;
+  breathing_period = value;
+}
+
+void breathing_period_default(void) {
+  breathing_period_set(BREATHING_PERIOD);
+}
+
+void breathing_period_inc(void)
+{
+  breathing_period_set(breathing_period+1);
+}
+
+void breathing_period_dec(void)
+{
+  breathing_period_set(breathing_period-1);
+}
+
+/* To generate breathing curve in python:
+ * from math import sin, pi; [int(sin(x/128.0*pi)**4*255) for x in range(128)]
+ */
+static const uint8_t breathing_table[BREATHING_STEPS] PROGMEM = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 17, 20, 24, 28, 32, 36, 41, 46, 51, 57, 63, 70, 76, 83, 91, 98, 106, 113, 121, 129, 138, 146, 154, 162, 170, 178, 185, 193, 200, 207, 213, 220, 225, 231, 235, 240, 244, 247, 250, 252, 253, 254, 255, 254, 253, 252, 250, 247, 244, 240, 235, 231, 225, 220, 213, 207, 200, 193, 185, 178, 170, 162, 154, 146, 138, 129, 121, 113, 106, 98, 91, 83, 76, 70, 63, 57, 51, 46, 41, 36, 32, 28, 24, 20, 17, 15, 12, 10, 8, 6, 5, 4, 3, 2, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
+
+// Use this before the cie_lightness function.
+static inline uint16_t scale_backlight(uint16_t v) {
+  return v / BACKLIGHT_LEVELS * get_backlight_level();
+}
+
+void custom_breathing_handler(void) {
+  uint16_t interval = (uint16_t) breathing_period * 244 / BREATHING_STEPS;
+  // resetting after one period to prevent ugly reset at overflow.
+  breathing_counter = (breathing_counter + 1) % (breathing_period * 244);
+  uint8_t index = breathing_counter / interval % BREATHING_STEPS;
+
+  if (((breathing_halt == BREATHING_HALT_ON) && (index == BREATHING_STEPS / 2)) ||
+      ((breathing_halt == BREATHING_HALT_OFF) && (index == BREATHING_STEPS - 1)))
+  {
+      // breathing_interrupt_disable();
+  }
+
+  setPWM(cie_lightness(scale_backlight((uint16_t) pgm_read_byte(&breathing_table[index]) * 0x0101U)));
+}
+
+#endif // BACKLIGHT_BREATHING
+#endif  // BACKLIGHT_ENABLE
diff --git a/keyboards/ymdk_np21/config.h b/keyboards/ymdk_np21/config.h
new file mode 100644
index 0000000000..2b358113d4
--- /dev/null
+++ b/keyboards/ymdk_np21/config.h
@@ -0,0 +1,54 @@
+/*
+Copyright 2017 Luiz Ribeiro <luizribeiro@gmail.com>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "config_common.h"
+
+#ifndef CONFIG_H
+#define CONFIG_H
+
+#define VENDOR_ID       0x20A0
+#define PRODUCT_ID      0x422D
+// TODO: share these strings with usbconfig.h
+// Edit usbconfig.h to change these.
+#define MANUFACTURER    ymdk
+#define PRODUCT         np21
+
+/* matrix size */
+#define MATRIX_ROWS 8
+#define MATRIX_COLS 15
+
+/* COL2ROW or ROW2COL */
+#define DIODE_DIRECTION COL2ROW
+
+#define BACKLIGHT_LEVELS 12
+// #define BACKLIGHT_BREATHING  // works, but BL_TOGG might not work
+
+#define TAPPING_TOGGLE 3
+
+#define NO_UART 1
+
+/* RGB underglow */
+// The RGB_DI_PIN value seems to be shared between all PS2AVRGB boards.
+// The same pin is used on the JJ40, at least.
+#define RGBLED_NUM 5
+#define RGB_DI_PIN E2 // NOTE: for PS2AVRGB boards, underglow commands are sent via I2C to 0xB0.
+#define RGBLIGHT_ANIMATIONS
+
+/* key combination for command */
+#define IS_COMMAND() (keyboard_report->mods == (MOD_BIT(KC_LSHIFT) | MOD_BIT(KC_RSHIFT)))
+
+#endif
diff --git a/keyboards/ymdk_np21/i2c.c b/keyboards/ymdk_np21/i2c.c
new file mode 100644
index 0000000000..c27f3e3d17
--- /dev/null
+++ b/keyboards/ymdk_np21/i2c.c
@@ -0,0 +1,104 @@
+/*
+Copyright 2016 Luiz Ribeiro <luizribeiro@gmail.com>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <avr/io.h>
+#include <util/twi.h>
+
+#include "i2c.h"
+
+void i2c_set_bitrate(uint16_t bitrate_khz) {
+    uint8_t bitrate_div = ((F_CPU / 1000l) / bitrate_khz);
+    if (bitrate_div >= 16) {
+        bitrate_div = (bitrate_div - 16) / 2;
+    }
+    TWBR = bitrate_div;
+}
+
+void i2c_init(void) {
+    // set pull-up resistors on I2C bus pins
+    PORTC |= 0b11;
+
+    i2c_set_bitrate(400);
+
+    // enable TWI (two-wire interface)
+    TWCR |= (1 << TWEN);
+
+    // enable TWI interrupt and slave address ACK
+    TWCR |= (1 << TWIE);
+    TWCR |= (1 << TWEA);
+}
+
+uint8_t i2c_start(uint8_t address) {
+    // reset TWI control register
+    TWCR = 0;
+
+    // begin transmission and wait for it to end
+    TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN);
+    while (!(TWCR & (1<<TWINT)));
+
+    // check if the start condition was successfully transmitted
+    if ((TWSR & 0xF8) != TW_START) {
+        return 1;
+    }
+
+    // transmit address and wait
+    TWDR = address;
+    TWCR = (1<<TWINT) | (1<<TWEN);
+    while (!(TWCR & (1<<TWINT)));
+
+    // check if the device has acknowledged the READ / WRITE mode
+    uint8_t twst = TW_STATUS & 0xF8;
+    if ((twst != TW_MT_SLA_ACK) && (twst != TW_MR_SLA_ACK)) {
+        return 1;
+    }
+
+    return 0;
+}
+
+void i2c_stop(void) {
+    TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);
+}
+
+uint8_t i2c_write(uint8_t data) {
+    TWDR = data;
+
+    // transmit data and wait
+    TWCR = (1<<TWINT) | (1<<TWEN);
+    while (!(TWCR & (1<<TWINT)));
+
+    if ((TWSR & 0xF8) != TW_MT_DATA_ACK) {
+        return 1;
+    }
+
+    return 0;
+}
+
+uint8_t i2c_send(uint8_t address, uint8_t *data, uint16_t length) {
+    if (i2c_start(address)) {
+        return 1;
+    }
+
+    for (uint16_t i = 0; i < length; i++) {
+        if (i2c_write(data[i])) {
+            return 1;
+        }
+    }
+
+    i2c_stop();
+
+    return 0;
+}
diff --git a/keyboards/ymdk_np21/i2c.h b/keyboards/ymdk_np21/i2c.h
new file mode 100644
index 0000000000..27c9d3d050
--- /dev/null
+++ b/keyboards/ymdk_np21/i2c.h
@@ -0,0 +1,25 @@
+/*
+Copyright 2016 Luiz Ribeiro <luizribeiro@gmail.com>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef __I2C_H__
+#define __I2C_H__
+
+void i2c_init(void);
+void i2c_set_bitrate(uint16_t bitrate_khz);
+uint8_t i2c_send(uint8_t address, uint8_t *data, uint16_t length);
+
+#endif
diff --git a/keyboards/ymdk_np21/keymaps/default/keymap.c b/keyboards/ymdk_np21/keymaps/default/keymap.c
new file mode 100644
index 0000000000..e79d326b7c
--- /dev/null
+++ b/keyboards/ymdk_np21/keymaps/default/keymap.c
@@ -0,0 +1,47 @@
+#include "ymdk_np21.h"
+#include "action_layer.h"
+
+#define _NP 0
+#define _BL  1
+
+enum custom_keycodes {
+  NP = SAFE_RANGE,
+  BL
+};
+
+const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
+/* Qwerty
+ * ,-----------------------------------------.
+ * |   0  |   1  |   4  |   7  | NUM  | ESC  |
+ * |------+------+------+------+------+------|
+ * |   .  |   2  |   5  |   8  |   /  | TAB  |---,
+ * |------+------+------+------+------+------|USB|
+ * |  DOT |   3  |   6  |   9  |   *  | BS   |---'
+ * |------+------+------+------+------+------|
+ * | Enter| Enter|   +  |   +  |   -  | FN   |
+ * `-----------------------------------------'
+ */
+[_NP] = KEYMAP( \
+  KC_KP_0,     KC_KP_1,     KC_KP_4,    KC_KP_7,    KC_NUMLOCK,     KC_ESC,    \
+  KC_DOT,      KC_KP_2,     KC_KP_5,    KC_KP_8,    KC_KP_SLASH,    KC_TAB,    \
+  KC_KP_DOT,   KC_KP_3,     KC_KP_6,    KC_KP_9,    KC_KP_ASTERISK, KC_BSPACE, \
+  KC_KP_ENTER, KC_KP_ENTER, KC_KP_PLUS, KC_KP_PLUS, KC_KP_MINUS,    MO(_BL)     \
+),
+/* Qwerty
+ * ,---------------------------------------------.
+ * | BL_BRTG |        |         |        |   |   |
+ * |---------+--------+---------+--------+---+---|
+ * |         | BL_OFF | BL_TOGG | BL_ON  |   |   |---,
+ * |---------+--------+---------+--------+---+---|USB|
+ * |         |        |         |        |   |   |---'
+ * |---------+--------+---------+--------+---+---|
+ * | BL_DEC  | BL_DEC | BL_INC  | BL_INC |   |   |
+ * `---------------------------------------------'
+ */
+[_BL] = KEYMAP( \
+  BL_BRTG, _______, _______, _______, _______, _______, \
+  _______, BL_OFF,  BL_TOGG, BL_ON,   _______, _______, \
+  _______, _______, _______, _______, _______, _______, \
+  BL_DEC,  BL_DEC,  BL_INC,  BL_INC,  _______, _______  \
+)
+};
diff --git a/keyboards/ymdk_np21/matrix.c b/keyboards/ymdk_np21/matrix.c
new file mode 100644
index 0000000000..a9e9cb5397
--- /dev/null
+++ b/keyboards/ymdk_np21/matrix.c
@@ -0,0 +1,118 @@
+/*
+Copyright 2017 Luiz Ribeiro <luizribeiro@gmail.com>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <avr/io.h>
+#include <util/delay.h>
+
+#include "matrix.h"
+
+#ifndef DEBOUNCE
+#   define DEBOUNCE	5
+#endif
+
+static uint8_t debouncing = DEBOUNCE;
+
+static matrix_row_t matrix[MATRIX_ROWS];
+static matrix_row_t matrix_debouncing[MATRIX_ROWS];
+
+void matrix_set_row_status(uint8_t row);
+uint8_t bit_reverse(uint8_t x);
+
+void matrix_init(void) {
+    // all outputs for rows high
+    DDRB = 0xFF;
+    PORTB = 0xFF;
+    // all inputs for columns
+    DDRA = 0x00;
+    DDRC &= ~(0x111111<<2);
+    DDRD &= ~(1<<PIND7);
+    // all columns are pulled-up
+    PORTA = 0xFF;
+    PORTC |= (0b111111<<2);
+    PORTD |= (1<<PIND7);
+
+    // initialize matrix state: all keys off
+    for (uint8_t row = 0; row < MATRIX_ROWS; row++) {
+        matrix[row] = 0x00;
+        matrix_debouncing[row] = 0x00;
+    }
+
+    matrix_init_quantum();  // missing from original port by Luiz
+}
+
+uint8_t matrix_scan(void) {
+    for (uint8_t row = 0; row < MATRIX_ROWS; row++) {
+        matrix_set_row_status(row);
+        _delay_us(5);
+
+        matrix_row_t cols = (
+            // cols 0..7, PORTA 0 -> 7
+            (~PINA) & 0xFF
+        ) | (
+            // cols 8..13, PORTC 7 -> 0
+            bit_reverse((~PINC) & 0xFF) << 8
+        ) | (
+            // col 14, PORTD 7
+            ((~PIND) & (1 << PIND7)) << 7
+        );
+
+        if (matrix_debouncing[row] != cols) {
+            matrix_debouncing[row] = cols;
+            debouncing = DEBOUNCE;
+        }
+    }
+
+    if (debouncing) {
+        if (--debouncing) {
+            _delay_ms(1);
+        } else {
+            for (uint8_t i = 0; i < MATRIX_ROWS; i++) {
+                matrix[i] = matrix_debouncing[i];
+            }
+        }
+    }
+
+    matrix_scan_quantum();  // also missing in original PS2AVRGB implementation
+
+    return 1;
+}
+
+void matrix_scan_kb(void) {
+  // Looping keyboard code goes here
+  // This runs every cycle (a lot)
+  matrix_scan_user();
+};
+
+// declarations
+void matrix_set_row_status(uint8_t row) {
+    DDRB = (1 << row);
+    PORTB = ~(1 << row);
+}
+
+uint8_t bit_reverse(uint8_t x) {
+    x = ((x >> 1) & 0x55) | ((x << 1) & 0xaa);
+    x = ((x >> 2) & 0x33) | ((x << 2) & 0xcc);
+    x = ((x >> 4) & 0x0f) | ((x << 4) & 0xf0);
+    return x;
+}
+
+inline matrix_row_t matrix_get_row(uint8_t row) {
+    return matrix[row];
+}
+
+void matrix_print(void) {
+}
diff --git a/keyboards/ymdk_np21/rules.mk b/keyboards/ymdk_np21/rules.mk
new file mode 100644
index 0000000000..670967fbd9
--- /dev/null
+++ b/keyboards/ymdk_np21/rules.mk
@@ -0,0 +1,59 @@
+# Copyright 2017 Luiz Ribeiro <luizribeiro@gmail.com>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# MCU name
+MCU = atmega32a
+PROTOCOL = VUSB
+
+# unsupported features for now
+NO_UART = yes
+NO_SUSPEND_POWER_DOWN = yes
+
+# processor frequency
+F_CPU = 12000000
+
+# Bootloader
+#     This definition is optional, and if your keyboard supports multiple bootloaders of
+#     different sizes, comment this out, and the correct address will be loaded
+#     automatically (+60). See bootloader.mk for all options.
+BOOTLOADER = bootloadHID
+
+# build options
+BOOTMAGIC_ENABLE = no
+MOUSEKEY_ENABLE = no
+EXTRAKEY_ENABLE = yes
+CONSOLE_ENABLE = no
+COMMAND_ENABLE = yes
+
+BACKLIGHT_ENABLE = yes
+BACKLIGHT_CUSTOM_DRIVER = yes
+
+RGBLIGHT_ENABLE = yes
+RGBLIGHT_CUSTOM_DRIVER = yes
+# DISABLE_WS2812 = no
+
+KEY_LOCK_ENABLE = yes
+
+# Do not enable SLEEP_LED_ENABLE. it uses the same timer as BACKLIGHT_ENABLE
+SLEEP_LED_ENABLE = no    # Breathing sleep LED during USB suspend
+
+OPT_DEFS = -DDEBUG_LEVEL=0
+
+# custom matrix setup
+CUSTOM_MATRIX = yes
+SRC = matrix.c i2c.c backlight.c
+
+# programming options
+PROGRAM_CMD = ./util/atmega32a_program.py $(TARGET).hex
diff --git a/keyboards/ymdk_np21/usbconfig.h b/keyboards/ymdk_np21/usbconfig.h
new file mode 100644
index 0000000000..ad97e7f0a3
--- /dev/null
+++ b/keyboards/ymdk_np21/usbconfig.h
@@ -0,0 +1,397 @@
+/* Name: usbconfig.h
+ * Project: V-USB, virtual USB port for Atmel's(r) AVR(r) microcontrollers
+ * Author: Christian Starkjohann
+ * Creation Date: 2005-04-01
+ * Tabsize: 4
+ * Copyright: (c) 2005 by OBJECTIVE DEVELOPMENT Software GmbH
+ * License: GNU GPL v2 (see License.txt), GNU GPL v3 or proprietary (CommercialLicense.txt)
+ * This Revision: $Id: usbconfig-prototype.h 785 2010-05-30 17:57:07Z cs $
+ */
+
+#ifndef __usbconfig_h_included__
+#define __usbconfig_h_included__
+
+#include "config.h"
+
+/*
+General Description:
+This file is an example configuration (with inline documentation) for the USB
+driver. It configures V-USB for USB D+ connected to Port D bit 2 (which is
+also hardware interrupt 0 on many devices) and USB D- to Port D bit 4. You may
+wire the lines to any other port, as long as D+ is also wired to INT0 (or any
+other hardware interrupt, as long as it is the highest level interrupt, see
+section at the end of this file).
+*/
+
+/* ---------------------------- Hardware Config ---------------------------- */
+
+#define USB_CFG_IOPORTNAME      D
+/* This is the port where the USB bus is connected. When you configure it to
+ * "B", the registers PORTB, PINB and DDRB will be used.
+ */
+#define USB_CFG_DMINUS_BIT      3
+/* This is the bit number in USB_CFG_IOPORT where the USB D- line is connected.
+ * This may be any bit in the port.
+ */
+#define USB_CFG_DPLUS_BIT       2
+/* This is the bit number in USB_CFG_IOPORT where the USB D+ line is connected.
+ * This may be any bit in the port. Please note that D+ must also be connected
+ * to interrupt pin INT0! [You can also use other interrupts, see section
+ * "Optional MCU Description" below, or you can connect D- to the interrupt, as
+ * it is required if you use the USB_COUNT_SOF feature. If you use D- for the
+ * interrupt, the USB interrupt will also be triggered at Start-Of-Frame
+ * markers every millisecond.]
+ */
+#define USB_CFG_CLOCK_KHZ       (F_CPU/1000)
+/* Clock rate of the AVR in kHz. Legal values are 12000, 12800, 15000, 16000,
+ * 16500, 18000 and 20000. The 12.8 MHz and 16.5 MHz versions of the code
+ * require no crystal, they tolerate +/- 1% deviation from the nominal
+ * frequency. All other rates require a precision of 2000 ppm and thus a
+ * crystal!
+ * Since F_CPU should be defined to your actual clock rate anyway, you should
+ * not need to modify this setting.
+ */
+#define USB_CFG_CHECK_CRC       0
+/* Define this to 1 if you want that the driver checks integrity of incoming
+ * data packets (CRC checks). CRC checks cost quite a bit of code size and are
+ * currently only available for 18 MHz crystal clock. You must choose
+ * USB_CFG_CLOCK_KHZ = 18000 if you enable this option.
+ */
+
+/* ----------------------- Optional Hardware Config ------------------------ */
+
+/* #define USB_CFG_PULLUP_IOPORTNAME   D */
+/* If you connect the 1.5k pullup resistor from D- to a port pin instead of
+ * V+, you can connect and disconnect the device from firmware by calling
+ * the macros usbDeviceConnect() and usbDeviceDisconnect() (see usbdrv.h).
+ * This constant defines the port on which the pullup resistor is connected.
+ */
+/* #define USB_CFG_PULLUP_BIT          4 */
+/* This constant defines the bit number in USB_CFG_PULLUP_IOPORT (defined
+ * above) where the 1.5k pullup resistor is connected. See description
+ * above for details.
+ */
+
+/* --------------------------- Functional Range ---------------------------- */
+
+#define USB_CFG_HAVE_INTRIN_ENDPOINT    1
+/* Define this to 1 if you want to compile a version with two endpoints: The
+ * default control endpoint 0 and an interrupt-in endpoint (any other endpoint
+ * number).
+ */
+#define USB_CFG_HAVE_INTRIN_ENDPOINT3   1
+/* Define this to 1 if you want to compile a version with three endpoints: The
+ * default control endpoint 0, an interrupt-in endpoint 3 (or the number
+ * configured below) and a catch-all default interrupt-in endpoint as above.
+ * You must also define USB_CFG_HAVE_INTRIN_ENDPOINT to 1 for this feature.
+ */
+#define USB_CFG_EP3_NUMBER              3
+/* If the so-called endpoint 3 is used, it can now be configured to any other
+ * endpoint number (except 0) with this macro. Default if undefined is 3.
+ */
+/* #define USB_INITIAL_DATATOKEN           USBPID_DATA1 */
+/* The above macro defines the startup condition for data toggling on the
+ * interrupt/bulk endpoints 1 and 3. Defaults to USBPID_DATA1.
+ * Since the token is toggled BEFORE sending any data, the first packet is
+ * sent with the oposite value of this configuration!
+ */
+#define USB_CFG_IMPLEMENT_HALT          0
+/* Define this to 1 if you also want to implement the ENDPOINT_HALT feature
+ * for endpoint 1 (interrupt endpoint). Although you may not need this feature,
+ * it is required by the standard. We have made it a config option because it
+ * bloats the code considerably.
+ */
+#define USB_CFG_SUPPRESS_INTR_CODE      0
+/* Define this to 1 if you want to declare interrupt-in endpoints, but don't
+ * want to send any data over them. If this macro is defined to 1, functions
+ * usbSetInterrupt() and usbSetInterrupt3() are omitted. This is useful if
+ * you need the interrupt-in endpoints in order to comply to an interface
+ * (e.g. HID), but never want to send any data. This option saves a couple
+ * of bytes in flash memory and the transmit buffers in RAM.
+ */
+#define USB_CFG_INTR_POLL_INTERVAL      1
+/* If you compile a version with endpoint 1 (interrupt-in), this is the poll
+ * interval. The value is in milliseconds and must not be less than 10 ms for
+ * low speed devices.
+ */
+#define USB_CFG_IS_SELF_POWERED         0
+/* Define this to 1 if the device has its own power supply. Set it to 0 if the
+ * device is powered from the USB bus.