Atmel AT91SAM7L-STK - Manual (Page 19)

Board Description
AT91SAM7L-STK Rev. B Starter Kit User Guide 4-5
6414A–ATARM–12-Sep-08
4.5 Memory
The AT91SAM7L128 embeds a total of 6 Kbytes high-speed SRAM, 128 Kbytes of high-speed internal
Flash for programming and 12 Kbytes of ROM for SAM-BA support.
4.6 Clock Circuitry
The clock generator of AT91SAM7L microcontroller is made up of one PLL, one fast RC oscillator, one
slow oscillator and one 32,768 Hz crystal oscillator. To start up the system very quickly, the 2-MHz RC
oscillator is automatically enabled after reset. Then it is up to the user to set and select the clock for mas-
ter clock. One may opt for the 32 kHz crystal or bypass mode if accurate RTC needed.
Figure 4-3. Block Diagram of Clock Generator
On AT91SAM7L-STK board, an external 32.768 KHz crystal is connected to AT91SAM7L128 dedicated
pins for external slow clock source. The external PLL filter circuit is also fitted (PLLRC).