Introduction
This page has been updated for Basic version 2, the original page is here
This is a description of the BV513 Hardware, the Ports, connections Jumpers and circuit diagram sections are all fully described.
The BV513 uses a 64 pin PIC32 Microcontroller, PIC32MX340F512H which runs at
a core clock rate of 80MHz, See the Specifications page for full details. The
BV513 outputs all of the PIC’s I/O via on board connectors. The deign is such
that it can be mounted on a matrix type
breadboard or used as a central platform for other peripherals.
The main interface is Via USB employing a virtual COM port that can be driven as
high as 2,000,000 Baud. All development work is done through this interface and
the USB also provides power to the board.
Contents
- Getting started
- Circuit Description
- USB Interface
- Micro SD Interface
- Power Supply
- Clocks
- Restoring the System
- Installing the Application Loader
Getting Started
The BV513 is ready to run out of the box, getting started is a question of
installing the USB driver so that it can talk to the host system.
The instructions are based around a Windows system but there are also USB
drivers available for Linux systems. A very comprehensive set of instructions
for installing the USB driver including for other operating systems are on the
CD-ROM in the installation guides directory. This should only be used as a last
resort, the following is an abbreviated version of how to install on Windows XP.
Step 1 Connect the BV513
Connect the BV513 to a spare USB port using the cable provided. The port can be USB versions 1.0 , 1.1 or 2.0. As this is a serial interface the speed of the USB is not important and will not effect the performance of the BV513.
Step 2 Install the USB Driver
The USB driver is located on the CD-ROM, assuming a Windows install, when
asked, choose 'install from a list or specific location'. The latest drivers and
installation documents can be obtained from
www.ftdichip.com. The
driver required is the VCP (Virtual Com Port). The VCP driver will install
itself as a new Com port.
New COM Port Installed
On this particular machine the new com port is port 33.
FTDI Confirmation
By double clicking on the new port it is possible to confirm that it is the correct one by looking at the manufacturers name (FTDI). Make a note of the port number as this will be needed for the next step.
Step 3 Sign On
Although any terminal software can be used it is recommended that BV-Com be used. This can be downloaded form the downloads page on this site.
PIC32-Basic Sign on (versions will differ)
Set the Baud rate to 115,200, 1 stop bit and 8 data bits as shown. Make sure the
port number you select matches the one just installed. Click on the red icon,
far left and this should turn green to show that a connection to the port has
been made.
The sign on message as shown in the figure should now appear, if not press the
reset icon
If you get a menu list instead of the sign on screen, press the reset again but don’t touch any keys at the keyboard, we will deal with the Application Loader menu later. Now go to the getting started text of the interface section.
Circuit Description
The BV513 has its own power regulators. The power is routed through two LDO regulators, one for 5V and the other for 3V3. The PIC and the USB interface operate on 3V3 and so the 5V regulator is provided for external interfaces and to provide isolation from the USB power supply in addition to extra stability for the 3v3 supply. There is a connector for powering the board, independent of the USB for stand alone applications.
Mounted on the board is a micro SD Card holder which is connected to the SPI
interface. This can be used for additional storage but the board comes with a
BIOS software that will read and write in FAT16 format enabling cards up to 2G
to be used.
The main processor is clocked internally at 80MHz and the default peripheral bus
speed is 40MHz. There is also a 32kHz RTC crystal controlled clock for system
use.
Block Diagram
The block diagram shows the power arrangements and connectors. The main off
board connection is via 4x16 way sockets laid out in a square arrangement.
The maximum current that can be drawn is determined by the 5V regulator which is
150mA.
Connectors
This is the master layout for all of the connectors, the legend on the PCB may vary form this and so any reference iin this text refers to these numbers.
JP1 & PW1
JP1 and PW1 provides the choice of power for the Microcontroller and peripheral connectors. The default is powered from the USB and this is achieved by shorting out the pins marked 1&2 (nearest the USB connector) with a jumper. When in this state the power is taken from the USB and PW1 has no effect. The USB is ‘shielded’ from short circuits by the voltage regulators.
When operating from a power source other than the USB, pins 2&3 of JP1 should be shorted. Power is now expected from the two pins marked PW1. This should be DC with a maximum of 10V. The +ve is indicated on the PCB.
Power from USB
The figure shows the jumper in position to take power form the USB (default).
When operating in this mode the USB FTDI chip is powered from the USB, however
when operating from an external source of power the FTDI chip is disabled to
save power.
Prog (set of 5 holes)
This set of pins allows a PICkit 2 to be connected so that the device may be
programmed without using the USB
Programming ***See Warning
The square pin on the Prog connector is pin 1 and this should go to the PICkit2
pin 1 which is marked on the PICkit2 body with a small triangle. The rest of the
pins are a 1 to 1 correspondence. Pin 6 on the PICkit2 is not used.
Pin Prog Connections
| 1 | Reset |
| 2 | 3V3 |
| 3 | GND |
| 4 | RB7 |
| 5 | RB6 |
The Application Loader hex file can be downloaded with the PIC programmer instead of using the boot-loader as described in the ‘restoring system software’ section. The hex file also includes the boot loader so it will still be in place.
JP2
(note R4 is 100R not 1k as stated)
The purpose of this jumper is to enable a selection of voltage references for
the AD convertor. The default is from the 3V3 supply and this is ‘hard wired’ as
a track on the PCB going from pin 2 to pin 3 on the top side of the PCB.
If the voltage from CVREF is required then this track can be cut and pins 1 & 2
shorted. Another alternative is for the user to supply an independent reference
to pin 2.
JP7
This jumper provides the hardware microcontroller reset (see also the USB Interface section) and the programming reset. Pin 2 is connected to ground.
Under normal conditions this jumper should be left open circuit. Momentarily
shorting pin 1 to pin 2 will cause the Microcontroller to perform a hardware
reset. The reset pin on the microcontroller is connected to pin 1 of JP7.
Pin 3 is connected to RF1 that has a 10k pull up resistor connected to it. At
start up the boot program monitors RF1 and goes into the boot process if it
detects that this pin is low. The boot process is described in a later section
on restoring the system.
Provided that this pin is high at start up, once the boot process has completed
it can be used for other purposes.
JP8
This connector has been provided to make connection of IASI, I2C and a second SD Card possible without the need for mounting the board and using the main connectors. All of the signals on this connector are also available on the main connectors. The layout and signal details are given in the appendix. See also the section on adding a second SD Card.
JP3 to JP6
This is the main expansion method for this board. The standard board is fitted with sockets that will take standard 2x8 pin connectors. The layout is on a 0.1 grid so that it can be plugged into a standard prototype board.
Prototype Board
Here is an example of a prototype board with a second SC card mounted and room
for lots of other hardware.
Prototype Board Underside
The underside of the board is wired with the ‘Roadrunner’ type wiring system.
This uses copper wire which has a special coating that melts when soldered so it
is insulated everywhere except at the connection. See
http://cpc.farnell.com for stocks.
The protoboards can be obtained form ByVac.
USB Interface
The USB interface is provided by an FT232RL chip that is supplied by www.ftdichip.com The drivers for this are supplied on CD_ROM but later versions are more likely to be found on the afore mentioned site. The driver required is the Virtual Com driver (VCOM) and as its name suggests creates a virtual COM port. This COM port is used to communicate with the microcontroller and also provide a reset function.
The drivers must be installed before the system can be used. In some Linux
distributions the drivers are already installed.
See the BV513 Interface Foundation for details of
installing the drivers.
U2RX,U2TX,RB8 and RB14 provided the serial communication to the microcontroller.
RB8 and RB14 provide the hardware handshake but by default this is disabled.
From this it should be noted that UART2 is the default communications channel.
UART1 is brought out on JP8 to act as the IASI communications but can simply be
used as a second UART if required.
_DTR is connected to the reset pin via a capacitor to toggling this either way
will cause a short pulse on the reset pin causing the microcontroller to perform
a hardware reset.
Micro SD Interface
There is a Micro SD card holder built onto the PCB which will accept a Micro SD card. The holder is wired through the SPI2 interface.
All of the signal lines have 10k pull up resistors. RF0 is used for the SPI chip select and RC12 (G4) is connected to a switch that connects this line to ground when a card is inserted. This enables the software to detect if a card is in place or not. The microcontroller will perform a hardware reset when some cards are inserted. This is due to the high initial current required by these cards.
Signal RC1 is also used; this is connected to an LED near the card holder and BV-Basic software will illuminate this when access is being made to the card.
Power Supply & LED
The power supply consists of two LDO regulators, one 5V on the other 3V3.
Depending on the selection at JP1 power is derived from either the USB or from an external source. All power goes initially through the 5V regulator to give better 3V3 regulation and so this must be considered when looking at the available power draw from the peripherals.
An LED is connected to the 3V3 supply to indicate that this is working. The other LED is general purpose but if used with BV-Basic is used to indicate SD Card access.
Clocks
The main Core Oscillator is 8MHz and derived internally. This can be increased to 80MHz by the internal PLL. An external 32KHz crystal is provided to drive the RTC clock and is connected to RC13 & RC14 which is the secondary clock input.
Restoring the System
This section describes how to restore the system using the hex and binary files
provided. This can also be used for any upgrades that may be available. The
software that can be installed via the USB is the Application Loader and the PIC32-Basic,
these are provided on three files:
appl.hex
bvb.bin (This may be called something else but will have a .bin extension)
Installing The Application Loader
This will only be needed if an upgrade of the Application
Loader is available. For example the upgrade from version 1.xx to 2.xx requires
the removal for the Micro-BOS and replacement with the Application loader. For
upgrading the application 'BV-Basic' see:
Reloading PIC32-Basic.
For installing a new Application Loader see the
Firmware Update Page.