hi,

probably this question I should ask Atmel about but they do answer so slowly. Maybe somebody already has answer by own tests.

The question. New derivatives AT89S8253 and AT89S2051/S4051 have been announced with old good-known feature "X2 clock". Their datasheets say that :
• Fully Static Operation: 0 Hz to 24 MHz
• Programmable and Fuseable x2 Clock Option.

Reading through datasheets I cannot determine is 24MHz max. frequency in X1 or X2 clock mode? Chapter "External Clock Drive Waveforms" shows in table that max. frequency of external clock drive is 24MHz and does not say about the clock mode yet.

For examle is it accesable configuration: OSC=18.432MHz and X2 mode enabled so MCU appears as 8051 at ~37MHz? Or 24MHz is limit for core and internal peripheral clock?

Thanks,
Oleg