Atmel AT43DK355, Руководство пользователя, Страница: 14 / 31

Hardware Description
3-2 AT43DK355 USB Controller Dev. Kit User Guide
3429C–USB–7/04
3.4 5x2 Header JP16
These headers are connected to one of each DIP switch.
3.5 DB 25 Female
Parallel Port
Connector J4
The parallel port connector, J4, is used for In-System Programming to upload firmware
from the PC to the SEEPROM U4. A DB25 male-to-male parallel cable is supplied to
connect the J4 connector to the PC parallel port. Further description on downloading
code to the SEEPROM is available in Section 3 of the USB Wizard: Application Exam-
ples and Demos document for the AT43USB355.
3.6 8-pin IC Socket
U4
The SEEPROM device is plugged to this 8-pin socket to store programming memory.
This board is supplied with an Atmel 25HP256 SEEPROM.
3.7 Variable Resistor
R15
Variable resistor R15 can be used to adjust voltage of the VREF pin of the AT43USB355
in order to test the Analog to Digital Converter (ADC) feature. This resistor produces
variable voltage levels that can be fed to the ADC input header (JP6 and JP5). The volt-
age produced from this resistor can be accessed from pin 4 of header JP9.
3.8 2x2 Header JP9
To use the ADC, a reference voltage must be applied to the VREF pin of the
AT43USB355. This reference voltage can be fixed at the CEXT voltage by setting a
jumper between pin 1 and pin 2, or the reference voltage can be adjustable (by adjusting
R15) by setting a jumper between pin 3 and pin 4 of J9.
JP9: 1-2 VREF = CEXTA (jumper installed by default)
3-4 VREF is adjustable
3.9 Programmable
Logic Device U2
This Development Board uses the ATF16V8CZ Electrical Erasable PLD for In-System
Programming and for downloading data from SEEPROM to AT43USB355.
3.10 5x2 Header JP5
and 2x2 Header
JP6
JP5 are input pins for ADC channels zero to seven and JP6 are for ADC channels eight
to eleven.
3.11 4x2 Header
General Purpose
I/O PORT A/JP1
Accessing PORTA externally can be performed at this header. A number is assigned to
each pin header, “0” to “7”, corresponds to the port's pin number.
3.12 4x2 Header
General Purpose
I/O PORT B/JP2
Accessing PORTB externally can be performed at this header. A number is assigned to
each pin header, “0” to “7”, corresponds to the port's pin number.