lator or an off-chip crystal oscillator. The off-chip oscillator can also drive the high-frequency
clock directly.
For the FE310-G002, the TileLink bus clock (
tlclk
) is fixed to be the same as the processor
core clock (
coreclk
).
The Always-On block includes a real-time clock circuit that is driven from one of the low-fre-
quency clock sources: an off-chip oscillator (LFOSC) or an an on-chip low-frequency oscillator
(LFROSC).
PRCI (Power, Reset, Clock, Interrupt) is an umbrella term for platform non-AON memory-
mapped control and status registers controlling component power states, resets, clock selection,
and low-level interrupts, hence the name. The PRCI registers are generally only made visible to
machine-mode software. The AON block contains registers with similar functions, but only for
the AON block units.
Table 8 shows the memory map for the PRCI on the FE310-G002.
Offset
Name
Description
0x00
hfrosccfg
Ring Oscillator Configuration and Status
0x04
hfxosccfg
Crystal Oscillator Configuration and Status
0x08
pllcfg
PLL Configuration and Status
0x0C
plloutdiv
PLL Final Divide Configuration
0xF0
procmoncfg
Process Monitor Configuration and Status
Internal Trimmable Programmable 72 MHz Oscillator
An internal trimmable high-frequency ring oscillator (HFROSC) is used to provide the default
clock after reset, and can be used to allow operation without an external high-frequency crystal
or the PLL.
The oscillator is controlled by the
hfrosccfg
register, which is memory-mapped in the PRCI
address space, and whose format is shown in Table 9.
Table 8:
SiFive PRCI memory map, offsets relative to PRCI base address.
Copyright © 2019, SiFive Inc. All rights reserved.
26
Содержание FE310-G002
Страница 1: ...SiFive FE310 G002 Manual v19p05 SiFive Inc ...
Страница 11: ...Figure 1 FE310 G002 top level block diagram Copyright 2019 SiFive Inc All rights reserved 9 ...
Страница 15: ...Chapter 2 List of Abbreviations and Terms 13 ...
Страница 23: ...Chapter 4 Memory Map The memory map of the FE310 G002 is shown in Table 4 21 ...