Atmel ATSTK500 500 Starter kit and development system. ATSTK500 ATSTK500 데이터 시트

1925C–AVR–3/03

VTARGET controls the supply voltage to the target AVR microcontroller sockets. It can
either be controlled from AVR Studio or supplied from an external source. If the VTAR-
GET jumper is mounted, the on-board supply voltage is connected. The on-board
supply voltage can be adjusted to 0 - 6V from AVR Studio. Always verify the respective
datasheet for the AVR device operating voltage before adjusting VTARGET voltage.

Using the on-board supply voltage, approximately 0.5A can be delivered to the target
section. See “Appendix A” in Section 10.

If the VTARGET jumper is disconnected, target V

CC

 must be supplied from an external

source at one of the VTG pins on the PORT headers. Figure 3-21 explains VTARGET
jumper options.

When using an external source for VTARGET, the user must control that VTARGET is
at a higher voltage level than AREF (analog reference voltage). Always connect com-
mon ground (GND) when using an external VTARGET voltage.

Figure 3-21.  VTARGET Jumper Options

The STK500 master microcontroller controls the target voltage using the internal PWM.
Figure 3-22 shows the internal connection of the VTARGET signal.

Figure 3-22.  VTARGET Connection

The green LED will light when there is a voltage available on the VTG NET. It’s 
impossible to use the debug or programming area of STK500 without VTG.

VTARGET

AREF

VTARGET

AREF

Jumper Mounted

Jumper not Mounted

On-board VTARGET supply connected (default)

On-board VTARGET supply disconnected

Master
MCU

VTARGET

PWM

VTG NET

Green LED

Jumper

Voltage
Regulator

10 - 15V

VIN

0 - 6V

Wr

Rd

ADC