Table 6:
Reset vector ROM
Address
Contents
0x1018
jr t0
This small gate ROM implements an
MSEL
-dependent jump for all cores as follows:
Table 7:
Target of the reset vector
MSEL
Reset address
Purpose
00
0x0000_1004
loops forever waiting for debugger
01
0x2000_0000
memory-mapped QSPI0
10
0x0002_0000
memory-mapped OTP
11
0x0001_0000
memory-mapped OTP
One-Time Programmable (OTP) Memory
The OTP is located on the peripheral bus, with both a control register interface to program the
OTP, and a memory read port interface to fetch words from the OTP. Instruction fetches from the
OTP memory read port are cached in the E31 core’s instruction cache.
The OTP needs to be programmed before use and can only be programmed by code running
on the core. The OTP bits contain all 0s prior to programming.
Quad SPI Flash Controller (QSPI)
The dedicated QSPI flash controller connects to external SPI flash devices that are used for
execute-in-place code. SPI flash is not available in certain scenarios such as package testing or
board designs not using SPI flash (e.g., just using on-chip OTP).
Off-chip SPI devices can vary in number of supported I/O bits (1, 2, or 4). SPI flash bits contain
all 1s prior to programming.
Chapter 5 Boot Process
FE310-G003 Manual
© SiFive, Inc.
Page 24
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