Programmers Model
ARM DUI 0447J
Copyright © 2009-2014, ARM. All rights reserved.
4-37
ID052914
Non-Confidential
Table 4-34
provides information on the timers.
At reset, the timers are clocked by a 32.768kHz reference from an external oscillator module.
You can, however, use the System Controller to change the timer reference from 32.768kHz to
1MHz.
4.5.10
UART
The PL011 PrimeCell UART is an AMBA-compliant SoC peripheral that is developed, tested,
and licensed by ARM. The 24MHz reference clock to the UARTs is from the crystal oscillator
that is part of
OSCCLK2
.
The internal registers of the UART peripheral are memory-mapped onto a static memory bus
chip select. The chip select that they map onto depends on the memory map your daughterboard
is using as follows:
•
ARM legacy memory map:
—
The registers map onto the CS7 chip select.
•
Cortex-A Series
memory map:
—
The registers map onto the CS3 chip select.
Note
See the Technical Reference Manual for your daughterboard.
Table 4-34 Timer implementation
Property
Value
Location Motherboard
IO
FPGA
Memory base address
•
ARM Legacy memory map:
—
Timer 0, 1: SMB CS7 base a
0x11000
—
Timer 2, 3: SMB CS7 base a
0x12000
•
ARM
Cortex-A Series
memory map:
—
Timer 0, 1: SMB CS3 base a
0x11000
—
Timer 2, 3: SMB CS3 base a
0x12000
Interrupt
•
Timer 0: TIM01INT[2]
•
Timer 1: TIM01INT[2]
•
Timer 2: TIM23INT[3]
•
Timer 3: TIM23INT[3]
DMA
None
Release version
ARM Dual-Timer SP804 r1p2
Platform Library support
timer_enable
Enables a timer with a given period and mode.
timer_disable
Disables the defined timer.
timer_interrupt_clear
Clears the timer interrupt.
Reference documentation
ARM
®
Dual-Timer Module (SP804) Technical Reference Manual