The maximum operating frequency of the MC9S12XD64MAA is 25 MHz, but it can be overclocked to 30 MHz with careful consideration of power consumption and thermal management.
The internal clock source can be configured using the Clock Monitor Unit (CMU) module. The CMU module allows you to select the clock source, divide the clock frequency, and enable or disable the clock output.
The MC9S12XD64MAA has 64 KB of RAM, but the maximum amount of RAM that can be used for stack and heap is limited to 32 KB due to the Harvard architecture of the processor.
The built-in bootloader can be accessed by pulling the MODE pin low during reset. The bootloader allows you to download code from an external source, such as a serial port or a flash memory device, into the internal flash memory.
The UART module supports baud rates up to 250 kbps, but the maximum baud rate that can be achieved depends on the clock frequency and the baud rate divisor.
MC9S12XD64MAA datasheet
by Freescale Semiconductor
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