Full family datasheet, 1.66 MB PDF, for the tiny25, tiny45 and tiny85, consistent with the Atmel AVR ATtiny25/45/85 8-pin microcontrollers. The variants share a pinout and differ in memory size. Contents should cover pin functions, clock sources and fuses, ADC, timers, USI, electrical characteristics and serial programming. On the bench it guides correct ISP wiring, shows how fuse settings such as reset disable affect programmability, and gives the voltage limits to check when a controller appears dead.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @datasheet. Enginerys does not host this file.
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The standard format for schematics, block diagrams, power-sequence charts and service manuals.