Modular Development Board

This board is essentially a breakout board for power, communication and IO ports to a microcontroller or other suitable device. Multiple minimal microcontroller boards can be connected and easily swapped out to have a full featured development board, that is not permanently tied to a single microcontroller.

TODO: list of modules

Dev board Connector

TODO

Pinout

Pin number	Function		Pin number	Function		Pin number	Function		Pin number	Function
1	GND		21	PORTA_6		41	PORTB_8		61	PORTD_2
2	GND		22	COMM_TX_2		42	ICSP4		62	PORTE_8
3	VBUS		23	PORTA_7		43	PORTC_1		63	PORTD_3
4	VBUS		24	COMM_RX_2		44	ICSP5		64	PORTE_7
5	5v		25	PORTA_8		45	PORTC_2		65	PORTD_4
6	5v		26	COMM_TX_3		46	ICSP6		66	PORTE_6
7	3v3		27	PORTB_1		47	PORTC_3		67	PORTD_5
8	3v3		28	COMM_RX_3		48	ICSP7		68	PORTE_5
9	1v8		29	PORTB_2		49	PORTC_4		69	PORTD_6
10	1v8		30	COMM_TX_4		50	ICSP8		70	PORTE_4
11	PORTA_1		31	PORTB_3		51	PORTC_5		71	PORTD_7
12	COMM_RTS_1		32	COMM_RX_4		52	ICSP9		72	PORTE_3
13	PORTA_2		33	PORTB_4		53	PORTC_6		73	PORTD_8
14	COMM_CTS_1		34	NC		54	ICSP10		74	PORTE_2
15	PORTA_3		35	PORTB_5		55	PORTC_7		75	NC
16	COMM_DTR_1		36	ICSP1		56	NC		76	PORTE_1
17	PORTA_4		37	PORTB_6		57	PORTC_8		77	VBUS
18	COMM_TX_1		38	ICSP2		58	RST_A		78	VBUS
19	PORTA_5		39	PORTB_7		59	PORTD_1		79	GND
20	COMM_RX_1		40	ICSP3		60	RST_B		80	GND

Power supply

Input power can be delivered through the external power (barrel jack or screw terminals) or the USB connector. Selecting power from either the external inputs or the USB connector can be done with the Power source jumper.

Input on the external power terminals should be in the range of 6 up to 15 volt. The polarity on the external input does not matter, the development board will correct the polarity.

TODO: Add current requirements.

The input power is regulated to 5V, 3.3V and 1.8V rails, which are all supplied to the development module. The module itself can pick one of those rails and feed that rail back as VCC. For all rails and the ground rail test points are supplied.

TODO: Add description of protection

Communication

There are four serial ports that modules can expose, one fully featured (TX, RX, DTR, CTS, RTS) and three basic (TX, RX only). The development board has a single USB to serial UART interface (FTDI FT232RL) connected to the USB input and the other end can be connected with the jumper interfaces to any of the four serial connections to the development module.

TODO: Add image of communication jumpers

There are two LED indicators for TX and RX activity.

Port modules

TODO

In Circuit Programming (ICP)

ICP Pin	AVR Function
1	MOSI
2	VCC (VBUS)
3	Unused (NC)
4	GND
5	RESET
6	GND
7	SCK
8	GND
9	MISO
10	GND