Atmel AVR ISP, Руководство пользователя

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Hardware Description
AVR
®
In System Programmer User Guide 3-3
To change the cable the AVRISP box must be opened and the correct cable must be
connected. See Figure 3-3 and Figure 3-4. Note that only one cable should be con-
nected at any given time. Make sure that the cable is mounted in the correct orientation.
Figure 3-3. AVRISP with 10-pin ISP Connector
Figure 3-4. AVRISP with 6-pin ISP Connector
3.4 Handling the ISP
Lines
When connecting the AVRISP to an external target some precautions should be taken.
In this section a few hints and tips will be given that should assure problem free commu-
nication between the AVRISP and target device.
The part can be programmed in-system from AVR Studio with In-System Programming
(ISP) in programming mode, running at the parts normal supply voltage.
For instruction on using the AVR studio programming software, see “Using AVR Studio”
on page 4.2
3.4.1 VCC and GND Connect the AVRISP ISP power lines to the appropriate pins on the AVR device (prefer-
ably through a 6 or 10-pin connector on the target board). Make sure the target voltage
is within specified range of the programmer (2.7V - 5.5V). Make sure that the target
power supply can deliver the additional power required to power the AVRISP at the
given voltage. See Section 8
3.4.2 SCK The target AVR samples the clock signal generated from the AVRISP. To make the
sampling robust, a target main clock, four times higher than the programming clock
(SCK), is required. By selecting the correct target speed in AVR Studio, the correct SCK
is automatically generated. The lowest supported target frequency is 8 kHz.
3.4.3 MOSI/MISO/SCK If the MOSI, MISO or SCK lines are used as general I/Os in the application, it is recom-
mended to use series resistors between the load and the AVR as shown in Figure 3-5.
The AVRISP lines should be connected directly to the AVR pins, without any series
resistors.
Note that the ISP lines are driven directly from an AVR microcontroller inside the
AVRISP. The resistors must be set according to this AVR’s maximum sink and source
currents and the application load. Refer to the AVR’s datasheet for the maximum sink
an d s o u rce c urre n t. D at as h e et s c a n b e d ow l oa de d f orm A tm el’s we b site ,
www.atmel.com.