Atmel AT43DK355, Руководство пользователя, Страница: 15 / 31

Hardware Description
AT43DK355 USB Controller Dev. Kit User Guide 3-3
3429C–USB–7/04
3.13 4x2 Header
General Purpose
I/O PORT D/JP4
Accessing PORTD 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.
3.14 2x2 Header
General Purpose
I/O JP3
External access to PF0 to PF3 is available at this header. These pins are used to down-
load programing from the SEEPROM to the AT43USB355E as soon as power is applied
to the board. Once firmware is downloaded, the AT43USB355 drives PF0 high while
leaving PF1-PF3 as a general purpose I/O. PF3 also has an alternate function as the
ICP input capture pin for the Timer/Counter1.
3.15 2x2 Header JP8.
This header will take effect whenever the Pulse Width Modulation (PWM) feature is
enabled. The 43USB355E has two PWM features, PWM1 and PWM2, which are output-
ting to PD5 (PORT D pin 5) and PD6 (PORT D pin 6). Installing jumpers to these pins,
connect PWM outputs to the base of transistors, Q2 and Q4 to amplify PWM signals. If
the PWM feature is disabled, PD5 and PD6 will be available as general purpose I/Os.
JP8: 1-2 PD5 = PWM1 (jumper installed by default)
3-4 PD6 = PWM2 (jumper installed by default)
3.16 2x2 Header JP13
There are three pins marked as PWM1, PWM2 and VBUS at this header. The PWM1
and PWM2 pins can be used to drive DC motors. The pin marked VBUS is the 5V USB
upstream port voltage.
3.17 2x2 Header JP11
This Development Board provides a ganged power switching and overcurrent sensing
features for two downstream USB ports. This feature occupies PD0 and PD1 and
requires the use of the Micrel MIC2026-2BM solid state power switch. The PD0 and
PD1 must be connected to this power switch by installing a jumper to this header. If this
system is not used, PD0 and PD1 will be available as general purpose I/Os.
JP11: 1-2 PD1 = Downstream USB power switching enable (jumper installed by default)
3-4 PD0 = Overcurrent protection enable (jumper installed by default)
3.18 Solid State
Power Switch U3
This device manages the ganged power switching system and overcurrent sensing fea-
ture. This board uses the Micrel MIC2026-2BM.
3.19 2x2 Header JP12
The pin marked as VBUS provides USB downstream port voltage. If the application
requires the use of the Micrel MIC2020-2BM for power switching and overcurrent pro-
tection, no jumpers are installed on JP12; otherwise, a jumper is needed between pin 1
and pin 2 of JP12.
JP12: 1-2 Connected = No power switching
Unconnected = Power switching (default)
3-4 No connection