Target System Requirements - Equinox Systems Micro-ISP IV Series User Manual

Micro-ISP

Target System Requirements

The following target system requirements must be met for the Micro-ISP programmer to
operate correctly :
• Target oscillator
The target microcontroller oscillator must be running between certain prescribed
frequencies. These can be found in the relevant microcontroller data sheets. The oscillator
could be an external crystal/resonator or could be an internal RC oscillator
(e.g AT90S1200 and AT90S2343).
• Power
The Micro-ISP requires a regulated DC supply to operate. This supply can be taken either
from the user target system or an external power supply unit (PSU). The programmer
should operate correctly between the specified operating voltage limits (see hardware
specifications).
• RESET circuit
The serial programming mode of the 89S
and AVR family devices is initiated by
asserting the RESET pin in the correct sense
for a certain period of time. The
programmer must, therefore, be able to
assert the RESET pin on the user target
microcontroller. External control of the
RESET pin can be implemented in a
number of different ways.
• SPI Enable Fuse
The SPI Enable Fuse (SPIEN) must be ENABLED in the target microcontroller device for ISP
programming to work. The SPIEN fuse can only be programmed in parallel programming
mode with the device in the ZIF socket. All Atmel microcontrollers are supplied from the
factory with the SPIEN fuse enabled as default.
IV User Manual V2.03
Series
Family
89S
AVR (90S)
ATmega
ATtiny
21
Reset Polarity
Active High
Active Low
Active Low
Active Low