Arduino Mega 1280 support

Fix ldflags

Update targets/arduino-mega1280.json

Co-authored-by: Ayke <aykevanlaethem@gmail.com>

Update atmega1280.json

Update Makefile

src/machine/machine_atmega1280.go

@@ -0,0 +1,138 @@
+// +build avr,atmega1280
+
+package machine
+
+import (
+	"device/avr"
+	"runtime/volatile"
+)
+
+const irq_USART0_RX = avr.IRQ_USART0_RX
+
+const (
+	portA Pin = iota * 8
+	portB
+	portC
+	portD
+	portE
+	portF
+	portG
+	portH
+	portJ
+	portK
+	portL
+)
+
+const (
+	PA0 = portA + 0
+	PA1 = portA + 1
+	PA2 = portA + 2
+	PA3 = portA + 3
+	PA4 = portA + 4
+	PA5 = portA + 5
+	PA6 = portA + 6
+	PA7 = portA + 7
+	PB0 = portB + 0
+	PB1 = portB + 1
+	PB2 = portB + 2
+	PB3 = portB + 3
+	PB4 = portB + 4
+	PB5 = portB + 5
+	PB6 = portB + 6
+	PB7 = portB + 7
+	PC0 = portC + 0
+	PC1 = portC + 1
+	PC2 = portC + 2
+	PC3 = portC + 3
+	PC4 = portC + 4
+	PC5 = portC + 5
+	PC6 = portC + 6
+	PC7 = portC + 7
+	PD0 = portD + 0
+	PD1 = portD + 1
+	PD2 = portD + 2
+	PD3 = portD + 3
+	PD7 = portD + 7
+	PE0 = portE + 0
+	PE1 = portE + 1
+	PE3 = portE + 3
+	PE4 = portE + 4
+	PE5 = portE + 5
+	PE6 = portE + 6
+	PF0 = portF + 0
+	PF1 = portF + 1
+	PF2 = portF + 2
+	PF3 = portF + 3
+	PF4 = portF + 4
+	PF5 = portF + 5
+	PF6 = portF + 6
+	PF7 = portF + 7
+	PG0 = portG + 0
+	PG1 = portG + 1
+	PG2 = portG + 2
+	PG5 = portG + 5
+	PH0 = portH + 0
+	PH1 = portH + 1
+	PH3 = portH + 3
+	PH4 = portH + 4
+	PH5 = portH + 5
+	PH6 = portH + 6
+	PJ0 = portJ + 0
+	PJ1 = portJ + 1
+	PK0 = portK + 0
+	PK1 = portK + 1
+	PK2 = portK + 2
+	PK3 = portK + 3
+	PK4 = portH + 4
+	PK5 = portH + 5
+	PK6 = portH + 6
+	PK7 = portH + 7
+	PL0 = portL + 0
+	PL1 = portL + 1
+	PL2 = portL + 2
+	PL3 = portL + 3
+	PL4 = portL + 4
+	PL5 = portL + 5
+	PL6 = portL + 6
+	PL7 = portL + 7
+)
+
+// getPortMask returns the PORTx register and mask for the pin.
+func (p Pin) getPortMask() (*volatile.Register8, uint8) {
+	switch {
+	case p >= PA0 && p <= PA7:
+		return avr.PORTA, 1 << uint8(p-portA)
+	case p >= PB0 && p <= PB7:
+		return avr.PORTB, 1 << uint8(p-portB)
+	case p >= PC0 && p <= PC7:
+		return avr.PORTC, 1 << uint8(p-portC)
+	case p >= PD0 && p <= PD7:
+		return avr.PORTD, 1 << uint8(p-portD)
+	case p >= PE0 && p <= PE6:
+		return avr.PORTE, 1 << uint8(p-portE)
+	case p >= PF0 && p <= PF7:
+		return avr.PORTF, 1 << uint8(p-portF)
+	case p >= PG0 && p <= PG5:
+		return avr.PORTG, 1 << uint8(p-portG)
+	case p >= PH0 && p <= PH6:
+		return avr.PORTH, 1 << uint8(p-portH)
+	case p >= PJ0 && p <= PJ1:
+		return avr.PORTJ, 1 << uint8(p-portJ)
+	case p >= PK0 && p <= PK7:
+		return avr.PORTK, 1 << uint8(p-portK)
+	case p >= PL0 && p <= PL7:
+		return avr.PORTL, 1 << uint8(p-portL)
+	default:
+		return avr.PORTA, 255
+	}
+}
+
+// SPI configuration
+var SPI0 = SPI{
+	spcr: avr.SPCR,
+	spdr: avr.SPDR,
+	spsr: avr.SPSR,
+	sck:  PB1,
+	sdo:  PB2,
+	sdi:  PB3,
+	cs:   PB0}