Datasheet

4.6 Testing the MCU after programming
Once the MCU has been programmed in the STK500 programmer, it can be tested by
using the BusPirate without removing the MCU from the STK500. Keep the wires as
short as possible and remember to disconnect the programming cable from the blue
SPROG1 header. Even here the combined length of the PCB ”wires” and the wires
connecting the BusPirate to the STK500 may be too long to facilitate trouble-free SPI
communication. In that case, simply remove the MCU from the STK500 programmer
and connect it directly to the BusPirate.
The BusPirate settings to be applied are m5121112 (refer to section 3.3.4 for details).
Figure 16: In this setup, the ATtiny25 is powered from the BusPirate. The STK500 power switch should
remain in the OFF position. Other test setups are also possible.
BusPirate pin name STK500 PORTB pin name ATtinyX5 pin (signal name)
MOSI PB0 PB0 (MOSI)
MISO PB1 PB1 (MISO)
CLK PB2 PB2 (SCK)
CS PB4 PB4 (CS/SS)
3V3 VTG VCC
GND GND GND
Table 4: Wiring diagram for connections between the BusPirate and the STK500 PORTB for testing
the programmed MCU. Also refer to table 2 for information regarding the required BusPirate 3V3/VPU
interconnection.
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