Intel Quark D2000 User manual

Document Number: 334476-001EN
Intel® Quark™Microcontroller D2000
BootROM Process
User Guide
May 2016

Intel® Quark™ Microcontroller D2000 BootROM
User Guide May 2016
2 Document Number: 334476-001EN
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Contents
1.0 Introduction............................................................................................................................................5
1.1 Terminology ......................................................................................................................................................5
1.2 Reference Documents ................................................................................................................................6
2.0 Flash Memory.........................................................................................................................................7
3.0 BootROM ...................................................................................................................................................8
3.1 Source Code......................................................................................................................................................8
3.2 Clock and Power Setup..............................................................................................................................8
3.2.1 Changing Clock Settings........................................................................................................9
3.3 JTAG Pins.............................................................................................................................................................9
3.4 Always on Periodic Timer (AONPT) Spurious Interrupt ................................................... 10
3.5 Setting the OTP Bit to Lock the BootROM ................................................................................. 10
3.6 Building and Flashing the ROM ......................................................................................................... 10
Figures
Figure 1. Flash Memory Map........................................................................................................................................7
Tables
Table 1. Terminology ......................................................................................................................................................5
Table 2. Reference Documents ................................................................................................................................6

Intel® Quark™ Microcontroller D2000 BootROM
User Guide May 2016
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Revision History
Date
Revision
Description
May 2016
001
Initial Release.
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Intel® Quark™ Microcontroller D2000 BootROM
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1.0 Introduction
The Intel® Quark™ microcontroller D2000 is an ultra-low power Intel Architecture (IA)
SoC that integrates an Intel® Quark™processor core, memory subsystem with on-die
volatile and non-volatile storage, and I/O interfaces into a single low-cost system-on-
chip solution.
This guide aims to explain the following:
Organization of the D2000 Flash Memory.
D2000 Boot process.
Options available to customize the Boot process.
For full technical specifications of the D2000, refer to the Intel® Quark™
Microcontroller D2000 Datasheet.
1.1 Terminology
Table 1. Terminology
Term
Description
BSP
Board Support Package –Refers to OS + Device Drivers
GPIO
General-Purpose Input/Output
JTAG
Joint Test Action Group
MCU
Microcontroller unit
OTP
One Time Programmable
POR
Power ON/Reset
QMSI
Intel® Quark™ Microcontroller Software Interface

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1.2 Reference Documents
Table 2. Reference Documents
Document
Document #/Location
Intel® Quark™Microcontroller D2000 Datasheet
333577
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2.0 Flash Memory
The Intel® Quark™ microcontroller D2000's Flash contains the following memories:
OTP Flash (8KB): Execution starts from OTP. The Region may be locked against
modification or erasure. The LMT Reset Vector is located in OTP Code region at
address 0x00000150.
Data Flash (4KB): Readable by OTP. May then be locked against reading by any
device (System Flash Application or DMA Controller).
System Flash (32KB): May contain code or data. Content may be loaded using
HMAC/SHA256 authenticated bootloader found in OTP Flash.
Figure 1. Flash Memory Map
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3.0 BootROM
3.1 Source Code
The BootROM contains the startup code for the processor to bring it up into 32-bit
protected mode. The source code can be found in the Board Support package (BSP).
<install_dir>/firmware/bsp/1.X/soc/quark_d2000/rom
rom_startup.s
rom_startup.c
The BSP is distributed with the toolchain for programming the D2000 - Intel® System
Studio for Microcontrollers, which is available to download at
https://registrationcenter.intel.com/en/forms/?productid=2580.
The BSP is also available on the Intel® Quark™ Microcontroller Software Interface Open
Source Repository at http://github.com/01org/qmsi.
3.2 Clock and Power Setup
When the processor is reset, it is clocked from the following:
BSP Version 1.0
32MHz crystal oscillator with a frequency of 32MHz.
BSP Version 1.1
onward
Internal silicon oscillator.
By default, all pins have a slew rate of 12 mA. The BootROM can set the initial clock
speed and GPIO pin slew rates using the hooks provided in the functions:
clock_Setup()
power_setup()

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3.2.1 Changing Clock Settings
BSP Version 1.0
To change the system clock mode, modify the following line of
code:
clk_sys_set_mode(CLK_SYS_CRYSTAL_OSC, CLK_SYS_DIV_1);
If selecting the hybrid oscillator as the system clock source, trim
codes may have to be calculated and applied to the osc0_cfg1
register.
BSP Version 1.1
onward
In BSP Version 1.1 onward the trim codes are calculated.
This can be modified if this policy does not match your specific
requirements.
3.3 JTAG Pins
The D2000's JTAG pins can be muxed with other functions (including UART1, PWMs,
and GPIOs). These pins have a default mux setting of JTAG functionality on POR. Once
they are assigned to a different function, it is impossible to access the TAP without a
reset.
It is essential that the JTAG TAP be accessed before any pin muxing happens and a
function is provided to implement a BootROM hook to guarantee enough time for a
JTAG access.
After the Clock and Power setup calls, the BootROM will test the state of one of the
GPIO pins. This pin is defined by the symbol WAIT_FOR_JTAG_PIN.
To use the function, select the GPIO pin to be used by updating the #define in this
line of code in rom_startup.c:
#define WAIT_FOR_JTAG_PIN (13)
Leave the pin unconnected, as there is a pull-up resistor inside the SoC. If your system
is in a noisy environment, then you may wish to fit a stronger pull-up resistor, such as a
4K7Ωto VDD. The BootROM will busy loop for as long as WAIT_FOR_JTAG_PIN is
grounded.
If this feature is not required, comment out the call to the function:
sense_jtag_probe();

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3.4 Always on Periodic Timer (AONPT) Spurious Interrupt
There is a chance that after a warm reset occurs, the PIC IRR register may be asserted
by the application. In this situation, the BootROM registers an interrupt service routine
(ISR) with the AONPT to catch this situation where the application would not have had a
chance to register its own ISR. This code is handled in the following function:
aon_handle_spurious_irq();
3.5 Setting the OTP Bit to Lock the BootROM
The BootROM may be locked to avoid accidental erasure by setting bit 0 of flash
memory location 0 to zero. Once done, the BootROM memory cannot be erased,
overwritten, or even read from. This is a security feature.
8KB OTP supports a hardware lock mechanism to prevent writes to and erases of OTP.
If bit 0 of offset 0x0 of the information memory region of Flash is 0b, the OTP region is
considered programmed, and hardware blocks all writes to and erases of information
memory.
To write to this address, add the following code to the rom_startup.c file:
<install_dir>/firmware/bsp/1.X/soc/quark_d2000/rom
rom_startup.c
Include qm_flash.h to enable flash access functions.
#include “qm_flash.h”
In the rom_startup function, add the following line of code:
qm_flash_word_write(QM_FLASH_0, QM_FLASH_REGION_OTP, 0, 0);
3.6 Building and Flashing the ROM
For full instructions on building and flashing the ROM from the command line, refer to
https://github.com/01org/qmsi.
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