A new developer board based on PIC18f27j53

In April 2011 I wrote about the PIC18F27J53 describing it like a monster for its capabilities, and I promise to build a development board with it.

And now this board is here!!!

The Pic18f27J53 has the following features:

Program Memory Type	Flash
Program Memory (KB)	128
CPU Speed (MIPS)	12
RAM Bytes	3800
Digital Communication Peripherals	2-A/E/USART, 2-MSSP(SPI/I2C)
Capture/Compare/PWM Peripherals	7 CCP, 3 ECCP
Timers	4 x 8-bit, 4 x 16-bit
ADC 10 ch, 12-bit
Comparators	3
USB (ch, speed, compliance)	1, Full Speed, USB 2.0
Temperature Range (C)	-40 to 85
Operating Voltage Range (V)	2 to 3.6
Pin Count	28
XLP	Yes
Cap Touch Channels	10

Now I’ve designed a little board that could be fit into a breadboard for fast prototype.

This board fits in the exact form factor of DIL600 28 pin with full pin-out compatibility.

The Board is the evolution of the PICCOLETTA board . I developed this board to fit the pic18f2550, and to learn how to use the USB interface. The PICCOLETTA PCB was modified to support the 3,3 volt pic (27j53, 26J53 …. ) using a 3,3 volt LDO Voltage regulator ( the mcp1700) , and I also provide the possibility to mount an electronic component for EMI filter and ESD protection. Actually I haven’t it and I replace with some resistors.

Characteristics:

Power supply can be selected, useing a jumper) between the USB port or an external board.
Power distribution from the USB port (5V) to the external board (150 ma MAX)
The oscillator can be excluded using a solder pad.
On board led can be used as power supply led or as test ping. The configuration has to be done using a solder pad.

Use

Enclosed into a dongle box it can be used for:

Security Key
Dongle Key
Security access (using the key as a rolling code)
Personal identification

Out from the dongle box

USB to RS232/TTL
USB to I2C
USB to SPI
TCP/UDP server (with an enc28j60)
Programmable I/O
LCD Controller Interface
RELAY I/O
MOTOR Controller

Finally it can be used as a developer Board.

The ICSP programming connector is present, it is compatible with pic-kit2 and 3/3. A solder pad is present on the connector to exclude PIN-6.

Fisical Dimension:

Length : 61,3 mm
Width : 18,2 mm
Height : 10,4 mm

Piccoletta2 can be programmed trough the USB.

Schematic

The BOM

Component	Value	Type
C1	220n	Metallized PE Film Capacitor C025-024X044
C2, C6, C7	0,1uF	Metallized PE Film Capacitor C025-024X044
C3, C8	10uF 18V	Tantalium Capacitor Electrolitic Radial (5x11x2,5)
C4, C5	18pf	Metallized PE Film Capacitor C050-024X044
R2, R5	10K 1%	Metal film resistor (0204) 0,4 Watt
R3	3,3K 1%	Metal film resistor (0204) 0,4 Watt
R1, R4	10 Ohm 1%	Metal film resistor (0204) 0,4 Watt
R7, R8	22 Ohm 1%	Resistor MINI_MELF-0204R (1206) 0,4 Watt
IC1	PIC18F27J53_28DIP	MIL 300 DIP28
IC2	MCP1700	TO93
IC2	MCP1700	Microchip LDO regulator 250mA
IC3	IP4220CZ6	SOT457R_PHILIPS
		It’s used for EMI filter and ESD protection
		ACTUALLY I HAVEN’T IT and UNUSED
L1	Led 3mm red	15 mcd 40° The power led
ICSP	6 pin header	ICSP PIC programming connector pin
		Pin 1 Vpp « MCLR pin pic
		Pin 2 Vcc «
		Pin 3 Gnd «
		Pin 4 PGD « PGD pin pic
		Pin 5 PGC « PGC pin pic
		Pin 6 PGM « PGM pin pic (could be unused)
T	1 pin header	Test pin led. (active low)
R	1 pin header	Button for bootloader selection. Actually it is not present in the board
JP2	2×3 pin header	Power selection see
S1	2 solder pad	Used to select the power supply
S2, S3	2 solder pad	Used to select the oscillator S2, S3 « closed (factory setting) select the on board oscillator.
S2, S3	2 solder pad	S2, S3 « open for future expansion
S4	2 solder pad	S4 « close (if the pic has the PGM pin)
S4	2 solder pad	S4 « open disconnect the PGM pin
Q1	Oscillator 12Mhz	HC49U-V
USB connector		USB-A-H