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|
|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|
|USB (ch, speed, compliance)||1, Full Speed, USB 2.0|
|Temperature Range (C)||-40 to 85|
|Operating Voltage Range (V)||2 to 3.6|
|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.
- 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.
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.
- Length : 61,3 mm
- Width : 18,2 mm
- Height : 10,4 mm
Piccoletta2 can be programmed trough the USB.
|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|
|Microchip LDO regulator 250mA|
|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 « open for future expansion|
|S4||2 solder pad||S4 « close (if the pic has the PGM pin)|
|S4 « open disconnect the PGM pin|
Board Layout and Setting Up
The J2 pinheader
Top view of the board (POV Ray)
Bottom view of the board (POV Ray)
Enclosed into USB dongle (POV Ray)
We have some board already soldered at low cost on ebay goto http://www.ebay.it/sch/giovannitto/m.html?_nkw=&_armrs=1&_from=&_ipg=&_trksid=p3686
First published on www.microprogrammo.it