Add sys/avr/lib

sys/avr/hello/main.c

@@ -0,0 +1,61 @@
+#include <u8g2.h>
+#include <util/delay.h>
+#include <u8x8_avr.h>
+
+#define P_CPU_NS (1000000000UL / F_CPU)
+
+u8g2_t u8g2;
+
+uint8_t u8x8_gpio_and_delay(u8x8_t *u8x8, uint8_t msg, uint8_t arg_int, void *arg_ptr)
+{
+  // Re-use library for delays
+  if(u8x8_avr_delay(u8x8, msg, arg_int, arg_ptr))
+    return 1;
+
+  switch(msg){
+    case U8X8_MSG_GPIO_AND_DELAY_INIT:  // called once during init phase of u8g2/u8x8
+      DDRB |= (1<<0); // CS
+      DDRB |= (1<<4); // DC
+      DDRA |= (1<<7); // RESET
+      break;              // can be used to setup pins
+    case U8X8_MSG_GPIO_CS:        // CS (chip select) pin: Output level in arg_int
+      if(arg_int)
+        PORTB |= (1<<0);
+      else
+        PORTB &= ~(1<<0);
+      break;
+    case U8X8_MSG_GPIO_DC:        // DC (data/cmd, A0, register select) pin: Output level in arg_int
+      if(arg_int)
+        PORTB |= (1<<4);
+      else
+        PORTB &= ~(1<<4);
+      break;
+    case U8X8_MSG_GPIO_RESET:     // Reset pin: Output level in arg_int
+      if(arg_int)
+        PORTA |= (1<<7);
+      else
+        PORTA &= ~(1<<7);
+      break;
+    default:
+      u8x8_SetGPIOResult(u8x8, 1);      // default return value
+      break;
+  }
+  return 1;
+}
+
+int main(void)
+{
+  u8g2_Setup_sh1106_128x64_vcomh0_f(
+    &u8g2, U8G2_R0,
+    u8x8_byte_avr_hw_spi,
+    u8x8_gpio_and_delay
+  );
+  u8g2_InitDisplay(&u8g2);
+  u8g2_SetPowerSave(&u8g2, 0);
+  while(1){
+    u8g2_ClearBuffer(&u8g2);
+    u8g2_SetFont(&u8g2, u8g2_font_ncenB14_tr);
+    u8g2_DrawStr(&u8g2, 0, 15, "Hello!");
+    u8g2_SendBuffer(&u8g2);
+  }
+}

sys/avr/at90usb1286/makefile → sys/avr/hello/makefile

@@ -4,6 +4,7 @@ SIZE = avr-size
 MCU = at90usb1286
 F_CPU = 16000000
 U8G2_SRC = ../../../csrc
+AVR_LIB_SRC = ../lib
 CFLAGS = \
 	-mmcu=$(MCU) \
 	-DF_CPU=$(F_CPU)UL \
@@ -12,12 +13,13 @@ CFLAGS = \
 	-Werror \
 	-ffunction-sections \
 	-fdata-sections \
-	-I$(U8G2_SRC)/
+	-I$(U8G2_SRC)/ \
+	-I$(AVR_LIB_SRC)
 LDFLAGS = \
 	-Wl,--gc-sections \
 	-mmcu=$(MCU)
 
-SRC = $(shell ls $(U8G2_SRC)/*.c) main.c
+SRC = $(shell ls $(U8G2_SRC)/*.c) $(shell ls $(AVR_LIB_SRC)/*.c) main.c
 
 OBJ = $(SRC:.c=.o)
 

sys/avr/lib/u8x8_avr.c

@@ -0,0 +1,79 @@
+#include "u8x8_avr.h"
+#include <util/delay.h>
+
+#define P_CPU_NS (1000000000UL / F_CPU)
+
+uint8_t u8x8_byte_avr_hw_spi(u8x8_t *u8x8, uint8_t msg, uint8_t arg_int, void *arg_ptr) {
+  uint8_t *data;
+
+  switch(msg) {
+    case U8X8_MSG_BYTE_INIT:
+      DDRB  |=  (1 << 1); // CLOCK (SCLK)
+      DDRB  |=  (1 << 2); // DATA (MOSI)
+      SPSR |= (1 << SPI2X); // SPI2X: Double SPI Speed bit
+      SPCR  = ((1 << SPE) | (1 << MSTR)); // Enable / Master
+      u8x8_gpio_SetCS(u8x8, u8x8->display_info->chip_disable_level);
+      break;
+    case U8X8_MSG_BYTE_SET_DC:
+      u8x8_gpio_SetDC(u8x8, arg_int);
+      break;
+    case U8X8_MSG_BYTE_START_TRANSFER:
+      u8x8_gpio_SetCS(u8x8, u8x8->display_info->chip_enable_level);
+      u8x8->gpio_and_delay_cb(u8x8, U8X8_MSG_DELAY_NANO, u8x8->display_info->post_chip_enable_wait_ns, NULL);
+      break;
+    case U8X8_MSG_BYTE_SEND:
+      data = (uint8_t *)arg_ptr;
+      while( arg_int > 0 ) {
+        SPDR = (uint8_t)*data;
+        while (!(SPSR & _BV(SPIF)));
+        data++;
+        arg_int--;
+      }
+      break;
+    case U8X8_MSG_BYTE_END_TRANSFER:
+      u8x8->gpio_and_delay_cb(u8x8, U8X8_MSG_DELAY_NANO, u8x8->display_info->pre_chip_disable_wait_ns, NULL);
+      u8x8_gpio_SetCS(u8x8, u8x8->display_info->chip_disable_level);
+      break;
+    default:
+      return 0;
+  }
+  return 1;
+}
+
+uint8_t u8x8_avr_delay(u8x8_t *u8x8, uint8_t msg, uint8_t arg_int, void *arg_ptr)
+{
+  uint8_t cycles;
+
+  switch(msg){
+    case U8X8_MSG_DELAY_NANO:     // delay arg_int * 1 nano second
+      // At 20Mhz, each cycle is 50ns, the call itself is slower.
+      break;
+    case U8X8_MSG_DELAY_100NANO:    // delay arg_int * 100 nano seconds
+      // Approximate best case values...
+      #define CALL_CYCLES 26UL
+      #define CALC_CYCLES 4UL
+      #define RETURN_CYCLES 4UL
+      #define CYCLES_PER_LOOP 4UL
+
+      cycles = (100UL * arg_int) / (P_CPU_NS * CYCLES_PER_LOOP);
+
+      if(cycles > CALL_CYCLES + RETURN_CYCLES + CALC_CYCLES) break;
+
+      __asm__ __volatile__ (
+        "1: sbiw %0,1" "\n\t" // 2 cycles
+        "brne 1b" : "=w" (cycles) : "0" (cycles) // 2 cycles
+      );
+      break;
+    case U8X8_MSG_DELAY_10MICRO:    // delay arg_int * 10 micro seconds
+      for(int i=0 ; i < arg_int ; i++)
+        _delay_us(10);
+      break;
+    case U8X8_MSG_DELAY_MILLI:      // delay arg_int * 1 milli second
+      for(int i=0 ; i < arg_int ; i++)
+        _delay_ms(1);
+      break;
+    default:
+      return 0;
+  }
+  return 1;
+}

sys/avr/lib/u8x8_avr.h

@@ -0,0 +1,5 @@
+#include <u8g2.h>
+#include <stdint.h>
+
+uint8_t u8x8_byte_avr_hw_spi(u8x8_t *u8x8, uint8_t msg, uint8_t arg_int, void *arg_ptr);
+uint8_t u8x8_avr_delay(u8x8_t *u8x8, uint8_t msg, uint8_t arg_int, void *arg_ptr);