Posted on January 23, 2006 at 00:29Quote:
On 22-01-2006 at 16:07, Anonymous wrote:
Question regarding ST ARM7:
a. In order to use processor special functions (UART, I2C etc). I need to alter the specific pin function to the appropriate function.
This is done using Port Configuration Registers.
Some pins have several alternate functions (Pin 0.8 can be used as and Rx (Full duplex UART) or Rx and TX (Single wire UART) – page 28 STR7x datasheet
my question is how to choose one of the alternate function when several are available?
b. STR7x offers 2 PLL’s PLL1 for the Core and Processor peripherals (APB1 and APB2) PLL2 for the USB and HDLC.
As a result minimal hardware PCB can use only one XTAL.
Does ST recommend a specific XTAL clock? (We prefer to the slowest XTAL possible 4Mhz)
Does ST recommend a specific hardware design (Single XTAL for the core and USB or several one)?
Pl's try to help .
Thx
Amir
use 4MHz clock to pll1 and pll2
