Features
• USB Protocol
– Based on the USB DFU class
– Autobaud (8/16 MHz crystal)
• In-System Programming
– Read/Write Flash and EEPROM on-chip memories
– Read Device ID
– Full chip Erase
– Start application command
• In-Application Programming
– Software Entry-points for on-chip flash drivers
1. Description
The 8bits mega AVR with USB interface devices are factory configured with a
USB bootloader located in the on-chip flash boot section of the controller.
This USB bootloader allows to perform In-System Programming from an USB
host controller without removing the part from the system or without a
pre-programmed application, and without any external programming interface.
This document describes the USB bootloader functionalities as well as the serial
protocol to efficiently perform operations on the on chip Flash memories (Flash
and EEPROM).
USB DFU
Bootloader
Datasheet
AT90USB128x
AT90USB64x
AT90USB162
AT90USB82
ATmega32U4
ATmega16U4
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2. Bootloader Environment
The bootloader is located in the boot section of the on-chip Flash memory, it manages the USB
communication protocol and performs read/write operations to the on-chip memories
(Flash/EEPROM).
The USB bootloader is loaded in the “Bootloader Flash Section” of the on-chip Flash memory.
The size of the bootloader flash section must be larger than the bootloader size.USB products
are factory configured with the default on-chip USB bootloader and the required bootsection
configuration.
Table 2-1.
USB Bootloader Parameters
Flash Bootsection Size
Configuration
VID / PID
Bootloader Start Address
(word address)
4 KWord
0x03EB / 0x2FFB
0xf000
0x03EB / 0x2FF9
0x7800
0x03EB / 0x2FFA
0x1800
AT90USB82
0x03EB / 0x2FF7
0x0800
ATmega32U4
0x03EB / 0x2FF4
0x3800
ATmega16U4
0x03EB / 0x2FF3
0x0800
Product
AT90USB1287
AT90USB1286
AT90USB647
AT90USB646
AT90USB162
2 KWord
Figure 2-1.
Physical Environment
DFU Class
USB
Interface
USB Bootloader
in Boot section
Read/Write
Read/Write
Flash
Application section
EEPROM Data
3. Bootloader Activation
As specified in the AT90USB datasheet, the bootloader can be activated by one of the following
conditions:
• Regular application execution: A jump or call from the user application program. This may
be initiated by a trigger such as a command received via USB, USART or SPI and decoded
by the application.
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• Boot Reset Fuse The Boot Reset Fuse (BOOTRST) can be programmed so that the Reset
Vector points to the Boot Flash section start address after reset. Once the user code is
loaded, a bootloader command (“start application”) can start executing the application code.
Note that the fuses cannot be changed by the MCU itself. This means that once the Boot
Reset Fuse is programmed, the Reset Vector will always point to the Bootloader Reset and
the fuse can only be changed through the serial or parallel programming interface. The
BOOTRST fuse is not active in the default factory configuration.
• External Hardware conditions The Hardware Boot Enable fuse (HWBE) can be
programmed so that upon special hardware conditions under reset, the bootloader execution
is forced after reset.
These different conditions are summarized in Figure 3-1 on page 3.
Boot Process
Reset
Yes
Ext Hardware
conditions
No
Yes
No
BOOTRST = 0
PC = boot loader section
Software Execution
Hardware Boot process
Figure 3-1.
"Software activation (jump)"
PC = 0000h
Application
Running
Start Bootloader
4. Protocol
4.1
Device Firmware Upgrade Introduction
Device Firmware Upgrade (DFU) is the mechanism implemented to perform device firmware
modifications. Any USB device can exploit this capability by supporting the requirements specified in this document.
Because it is unpractical for a device to concurrently perform both DFU operations and its normal run-time activities, these normal activities must cease for the duration of the DFU
operations. Doing so means that the device must change its operating mode; i.e., a printer is not
a printer while it is undergoing a firmware upgrade; it is a PROM programmer. However, a
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device that supports DFU is not capable of changing its mode of operation on its own. External
(human or host operating system) intervention is required.
4.2
DFU Specific Requests
In addition to the USB standard requests, 7 DFU class-specific requests are used to accomplish
the upgrade operations:
Table 4-1.
DFU Class-specific Requests
bmRequestType
bRequest
wValue
wIndex
wLength
Data
0010 0001b
DFU_DETACH (0)
wTimeout
Interface (4)
Zero
none
0010 0001b
DFU_DNLOAD (1)
wBlock
Interface (4)
Length
Firmware
1010 0001b
DFU_UPLOAD (2)
wBlock
Interface (4)
Length
Firmware
1010 0001b
DFU_GETSTATUS (3)
Zero
Interface (4)
6
Status
0010 0001b
DFU_CLRSTATUS (4)
Zero
Interface (4)
Zero
none
1010 0001b
DFU_GETSTATE (5)
Zero
Interface (4)
1
State
0010 0001b
DFU_ABORT (6)
Zero
Interface (4)
Zero
none
4.3
DFU Descriptors Set
The device exports the DFU descriptor set, which contains:
• A DFU device descriptor
• A single configuration descriptor
• A single interface descriptor (including descriptors for alternate settings, if present)
4.3.1
DFU Device Descriptor
This descriptor is only present in the DFU mode descriptor set. The DFU class code is reported
in the bDeviceClass field of this descriptor.
Table 4-2.
DFU Mode Device Descriptor
Offset
Field
Size
Value
Description
0
bLength
1
12h
Size of this descriptor, in bytes
1
bDescriptorType
1
01h
DFU functional descriptor type
2
bcdUSB
2
0100h
4
bDeviceClass
1
FEh
Application Specific Class Code
5
bDeviceSubClass
1
01h
Device Firmware Upgrade Code
6
bDeviceProtocol
1
00h
The device does not use a class specific protocol on this interface
7
bMaxPacketSize0
1
32
Maximum packet size for endpoint zero (limited to 32 due to Host side
driver)
8
idVendor
2
03EBh
Vendor ID
10
idProduct
2
2FFBh
Product ID
12
bcdDevice
2
0x0000
Device release number in binary coded decimal
14
iManufacturer
1
0
USB specification release number in binary coded decimal
Index of string descriptor
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Offset
Field
Size
Value
15
iProduct
1
0
Index of string descriptor
16
iSerialNumber
1
0
Index of string descriptor
17
bNumConfigurations
1
01h
4.3.2
Description
One configuration only for DFU
DFU Configuration Descriptor
This descriptor is identical to the standard configuration descriptor described in the USB DFU
specification version 1.0, with the exception that the bNumInterfaces field must contain the value
01h.
4.3.2.1
DFU Interface Descriptor
This is the descriptor for the only interface available when operating in DFU mode. Therefore,
the value of the bInterfaceNumber field is always zero.
Table 4-3.
DFU Mode Interface Description
Offset
Field
Size
Value
Description
0
bLength
1
09h
Size of this descriptor, in bytes
1
bDescriptorType
1
04h
INTERFACE descriptor type
2
bInterfaceNumber
1
00h
Number of this interface
3
bAlternateSetting
1
00h
Alternate setting(1)
4
bNumEndpoints
1
00h
Only the control pipe is used
5
bInterfaceClass
1
FEh
Application Specific Class Code
6
bInterfaceSubClass
1
01h
Device Firmware Upgrade Code
7
bInterfaceProtocol
1
00h
The device does not use a class specific protocol on this interface
8
iInterface
1
00h
Index of the String descriptor for this interface
Note:
1. Alternate settings can be used by an application to access additional memory segments. In this case, it is suggested that
each alternate setting employ a string descriptor to indicate the target memory segment; e.g., “EEPROM”. Details concerning other possible uses of alternate settings are beyond the scope of this document. However, their use is intentionally not
restricted because the authors anticipate that implements will devise additional creative uses for alternate settings.
4.4
Commands Description
The protocol implemented in the AT90USB bootloader allows to:
• Initiate the communication
• Program the Flash or EEPROM Data
• Read the Flash or EEPROM Data
• Program Configuration Information
• Read Configuration and Manufacturer Information
• Erase the Flash
• Start the application
Overview of the protocol is detailed in “Appendix-A” on page 18.
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4.5
4.5.1
Device Status
Get Status
The Host employs the DFU_GETSTATUS request to facilitate synchronization with the device.
This status gives information on the execution of the previous request: in progress/OK/Fail/...
bmRequestType
bRequest
wValue
wIndex
wLength
Data
1010 0001b
DFU_GETSTATUS (3)
Zero
Interface (4)
6
Status
0010 0001b
DFU_CLRSTATUS (4)
Zero
Interface (4)
Zero
none
The device responds to the DFU_GETSTATUS request with a payload packet containing the following data:
Table 4-4.
DFU_GETSTATUS Response
Offset
Field
Size
Value
0
bStatus
1
Number
Description
An indication of the status resulting from the
execution of the most recent request.
1
bwPollTimeOut
3
Minimum time in milliseconds that the host should
wait before sending a subsequent
DFU_GETSTATUS. The purpose of this field is to
allow the device to dynamically adjust the amount of
Number
time that the device expects the host to wait
between the status phase of the next
DFU_DNLOAD and the subsequent solicitation of
the device’s status via DFU_GETSTATUS.
4
bState
1
An indication of the state that the device is going to
Number enter immediately following transmission of this
response.
5
iString
1
Table 4-5.
Index
Index of status description in string table.
bStatus values
Status
Value
Description
OK
0x00
No error condition is present
errTARGET
0x01
File is not targeted for use by this device
errFILE
0x02
File is for this device but fails some vendor-specific verification test
errWRITE
0x03
Device id unable to write memory
errERASE
0x04
Memory erase function failed
errCHECK_ERAS
ED
0x05
Memory erase check failed
errPROG
0x06
Program memory function failed
errVERIFY
0x07
Programmed memory failed verification
errADDRESS
0x08
Cannot program memory due to received address that is out of range
errNOTDONE
0x09
Received DFU_DNLOAD with wLength = 0, but device does not think it has all the
data yet.
errFIRMWARE
0x0A
Device’s firmware is corrupted. It cannot return to run-time operations
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Status
Value
Description
errVENDOR
0x0B
iString indicates a vendor-specific error
errUSBR
0x0C
Device detected unexpected USB reset signaling
errPOR
0x0D
Device detected unexpected power on reset
errUNKNOWN
0x0E
Something went wrong, but the device does not know what it was
errSTALLEDPK
0x0F
Device stalled an unexpected request
Table 4-6.
bState Values
State
Value
Description
appIDLE
0
Device is running its normal application
appDETACH
1
Device is running its normal application, has received the DFU_DETACH
request, and is waiting for a USB reset
dfuIDLE
2
Device is operating in the DFU mode and is waiting for requests
dfuDNLOAD-SYNC
3
Device has received a block and is waiting for the Host to solicit the status via
DFU_GETSTATUS
dfuDNBUSY
4
Device is programming a control-write block into its non volatile memories
dfuDNLOAD-IDLE
5
Device is processing a download operation. Expecting DFU_DNLOAD requests
Device has received the final block of firmware from the Host and is waiting for
receipt of DFU_GETSTATUS to begin the Manifestation phase
dfuMANIFEST-SYNC
6
or
device has completed the Manifestation phase and is waiting for receipt of
DFU_GETSTATUS.
4.5.2
dfuMANIFEST
7
Device is in the Manifestation phase.
dfuMANIFEST-WAITRESET
8
Device has programmed its memories and is waiting for a USB reset or a power
on reset.
dfuUPLOAD-IDLE
9
The device is processing an upload operation. Expecting DFU_UPLOAD
requests.
dfuERROR
10
An error has occurred. Awaiting the DFU_CLRSTATUS request.
Clear Status
Each time the device detects and reports an error indication status to the host in response to a
DFU_GETSTATUS request, it enters the dfuERROR state. After reporting any error status, the
device can not leave the dfuERROR state, until it has received a DFU_CLRSTATUS request.
Upon receipt of DFU_CLRSTATUS, the device sets status to OK and move to the dfuIDLE state.
Once the device is in the dfuIDLE state it is then able to move to other states.
bmRequestType
bRequest
wValue
wIndex
wLength
Data
0010 0001b
DFU_CLRSTATUS (4)
Zero
Interface (4)
0
None
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4.5.3
Device State
The state reported is the current state of the device up to transmission of the response. The values specified in the bState field are identical to those reported in DFU_GETSTATUS.
4.5.4
4.6
bmRequestType
bRequest
wValue
wIndex
wLength
Data
1010 0001b
DFU_GETSTATE (5)
Zero
Interface (4)
1
State
DFU_ABORT request
The DFU_ABORT request forces the device to exit from any other state and return to the
DFU_IDLE state. The device sets the OK status on receipt of this request. For more information,
see the corresponding state transition summary.
bmRequestType
bRequest
wValue
wIndex
wLength
Data
1010 0001b
DFU_ABORT (6)
Zero
Interface (4)
0
None
Programming the Flash or EEPROM Data
The firmware image is downloaded via control-write transfers initiated by the DFU_DNLOAD
class-specific request. The host sends between bMaxPacketSize0 and wTransferSize bytes to
the device in a control-write transfer. Following each downloaded block, the host solicits the
device status with the DFU_GETSTATUS request.
As described in the USB DFU Specification, "Firmware images for specific devices are, by definition, vendor specific. It is therefore required that target addresses, record sizes, and all other
information relative to supporting an upgrade are encapsulated within the firmware image file. It
is the responsibility of the device manufacturer and the firmware developer to ensure that their
devices can process these encapsulated data. With the exception of the DFU file suffix, the content of the firmware image file is irrelevant to the host."
Firmware image:
• 32 bytes: Command
• X bytes: X is the number of byte (00h) added before the first significant byte of the firmware.
The X number is calculated to align the beginning of the firmware with the flash page. X =
start_address [32]. For example, if the start address is 00AFh (175d), X = 175 [32] = 15.
• The firmware
• The DFU Suffix on 16 Bytes.
Table 4-7.
Offset
DFU File Suffix
Field
Size
Value
Description
The CRC of the entire file, excluding dwCRC
-0
dwCRC
4
Number
-4
bLength
1
16
-5
ucDfuSignature
3
The length of this DFU suffix including dwCRC
5 : 44h
6 : 46h
The unique DFU signature field
7 : 55h
-8
bcdDFU
2
BCD
0100h
DFU specification number
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Offset
4.6.1
4.6.1.1
Field
Size
Value
Description
-10
idVendor
2
ID
The vendor ID associated with this file. Either FFFFh or
must match device’s vendor ID
-12
idProduct
2
ID
The product ID associated with this file. Either FFFFh or
must match the device’s product ID
-14
bcdDevice
2
BCD
The release number of the device associated with this
file. Either FFFFh or a BCD firmware release or version
number
Request From Host
bmRequestType
bRequest
wValue
wIndex
wLength
Data
0010 0001b
DFU_DNLOAD (1)
wBlock
Interface (4)
Length
Firmware
Write Command
Command Identifier
data[0]
Id_prog_start
00h
01h
01h
data[1]
data[2]
data[3]
data[4]
Description
Init FLASH programming
start_address
end_address
Init EEPROM programming
The write command is 6 bytes long. In order to meet with the USB specification of the Control
type transfers, the write command is completed with 26 (= 32 - 6) non-significant bytes. The total
length of the command is then 32 bytes, which is the length of the Default Control Endpoint.
4.6.1.2
Firmware
The firmware can now be downloaded to the device. In order to be in accordance with the Flash
page size (128 bytes), X non-significant bytes are added before the first byte to program. The X
number is calculated to align the beginning of the firmware with the Flash page. X =
start_address [32]. For example, if the start address is 00AFh (175d), X = 175 [32] = 15.
4.6.1.3
DFU Suffix
The DFU suffix of 16 bytes is added just after the last byte to program. This suffix is reserved for
future use.
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Figure 4-1.
Example of Firmware Download Zero Length DFU_DNLOAD Request
SETUP
DFU_DNLOAD
OUT
Prog_Start + (EP0 fifo length - 6) x 00h
OUT
X offset bytes + Firmware Packet 1
OUT
Firmware Packet 2
OUT
Firmware Packet n + DFU suffix
IN
ZLP
The Host sends a DFU_DNLOAD request with Zero Length Packet (ZLP) to indicate that it has
completed transferring the firmware image file. This is the final payload packet of a download
operation.
4.6.1.4
4.7
Answers from Bootloader
After each program request, the Host can request the device state and status by sending a
DFU_GETSTATUS message.
If the device status indicates an error, the host must send a DFU_CLRSTATUS request to the
device.
Reading the Flash or EEPROM Data
The flow described below allows the user to read data in the Flash memory or in the EEPROM
data memory. A blank check command on the Flash memory is possible with this flow.
This operation is performed in 2 steps:
• DFU_DNLOAD request with the read command (6 bytes)
• DFU_UPLOAD request which correspond to the previous command.
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4.7.1
First Request from Host
The Host sends a DFU Download request with a Display command in the data field.
Command Identifier
SETUP
DFU_DNLOAD
OUT
Display_Data (6 bytes)
IN
ZLP
data[0]
data[1]
data[2]
data[3]
data[4]
00h
Id_display_data
03h
Description
Display FLASH Data
01h
start_address
02h
end_address
Blank Check in FLASH
Display EEPROM Data
4.7.2
Second Request from Host
The Host sends a DFU Upload request.
4.7.3
Answers from the Device
The device sends to the Host the firmware from the specified start address to the specified end
address.
SETUP
DFU_UPLOAD
IN
Firmware Packet 1
IN
Firmware Packet 2
IN
Firmware Packet n
OUT
ZLP
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4.7.4
Answers from the Device to a Blank Check Command
The Host controller sends a GET_STATUS request to the device. Once internal blank check has
been completed, the device sends its status.
• If the device status is “OK”:
the device memory is then blank and the device waits for the next Host request.
• If the device status is “errCHECK_ERASED”:
the device memory is not blank. The device waits for an DFU_UPLOAD request to send the
first address where the byte is not 0xFF.
4.8
Reading Configuration Information or Manufacturer Information
The flow described hereafter allows the user to read the configuration or manufacturer
information.
4.8.1
Requests From Host
To start the programming operation, the Host sends DFU_DNLOAD request with the Read command in the data field (2 bytes).
DFU_DNLOAD
SETUP
Read_command (2 bytes)
OUT
ZLP
IN
Command Identifier
data[0]
00h
Id_read_command
05h
data[1]
data[2]
data[3]
data[4]
Description
00h
Read Bootloader Version
01h
Read Device boot ID1
02h
Read Device boot ID2
30h
Read Manufacturer Code
31h
Read Family Code
60h
Read Product Name
61h
Read Product Revision
01h
4.8.2
Answers from Bootloader
The device has two possible answers to a DFU_GETSTATUS request:
• If the chip is protected from program access, an “err_VENDOR” status is returned to the
Host.
• Otherwise, the device status is “OK“. The Host can send a DFU_UPLOAD request to the
device in order to get the value of the requested field.
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DFU_UPLOAD
SETUP
Byte value (1 byte)
IN
ZLP
OUT
4.9
Erasing the Flash
The flow described below allows the user to erase the Flash memory.
The Full Chip erase command erases the whole Flash.
4.9.1
Request from Host
To start the erasing operation, the Host sends a DFU_DNLOAD request with a Write Command
in the data field (2 bytes).
Command Identifier
Id_write_command
04h
4.9.2
data[0]
data[1]
00h
FFh
data[2]
data[3]
data[4]
Description
Full chip Erase (bits at FFh)
Answers from Bootloader
The device has two possible answers to a DFU_GETSTATUS request:
• If the chip is protected from program access, an “err_WRITE” status is returned to the Host.
• Otherwise, the device status is “OK“.
4.10
Starting the Application
The flow described below allows to start the application directly from the bootloader upon a specific command reception.
Two options are possible:
•
Start the application with an internal hardware reset using watchdog.
When the device receives this command the watchdog is enabled and the bootloader enters
a waiting loop until the watchdog resets the device.
•
Start the application without reset.
A jump at the address 0000h is used to start the application without reset.
To start the application, the Host sends a DFU_DNLOAD request with the specified application
start type in the data field (3 or 5 bytes).
This request is immediately followed by a second DFU_DNLOAD request with no data field to
start the application with one of the 2 options.
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Important note:
The bootloader performs a watchdog reset to generate the “hardware reset” that allows to execute the application section. After a watchdog reset occurs, the AVR watchdog is still running,
thus the application should take care to disable watchdog at program start-up (otherwise the
application that does not manage the hardware watchdog will run in an infinite reset loop).
4.11
Request From Host
DFU_UPLOAD
SETUP
Jump Option (3 or 5 Bytes)
IN
Command Identifier
OUT
ZLP
SETUP
DFU_UPLOAD
data[0]
Id_write_command
04h
data[1]
data[3]
00h
data[4]
Description
Hardware reset
03h
01h
4.12
data[2]
address
LJMP address
Answer from Bootloader
No answer is returned by the device.
5. Security
When the USB bootloader connection is initiated, the bootloader automatically enters a
read/write software security mode (independent of the product lock bits settings). This allows to
protect the on-chip flash content from read/write access over the USB interface. Thus the only
DFU command allowed after a USB bootloader connection is a “Full Chip Erase” command.
After this “Full Chip Erase” has been received and properly executed, all DFU commands are
allowed, and thus the on-chip flash can be reprogrammed and verified.
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6. Accessing the Low level Flash Drivers
The AT90USB USB bootloader is located in the boot section of the on-chip flash memory, meanwhile the bootloader section is the unique memory location allowed to execute on-chip flash
memory write operations (SPM instruction is decoded only in this section).
Thus applications which require on-chip flash write access can perform calls to specific entry
points located in the USB bootloader.
The USB bootloader provides several Application Programming Interfaces (API) that allows the
application to access low level flash drivers located in the boot section. These APIs allow the following operations:
• Page Erase
• Page Write
• Load word in the temporary page buffer
Figure 6-1.
USB bootloader API calls
USB Bootloader
API entry points
Boot section
Low level flash drivers
On-Chip flash Request:
"Page Erase"
"Page Write"
"Load Word"
Low Level
Flash Operations
Application
Application section
Target Page modified
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The API are located at absolute addresses in the USB bootloader firmware and accept specific
registers values as parameters. These parameters are compatible with a C compiler calling convention and thus can be called directly with function pointer declared as in the example below:
C Code Example
#if (FLASH_END==0x1FFFF) //128K bytes parts
#define LAST_BOOT_ENTRY
0xFFFE
#elif (FLASH_END==0xFFFF)//64K bytes parts
#define LAST_BOOT_ENTRY
0x7FFE
#else
#error You must define FLASH_END in bytes.
#endif
// These functions pointers are used to call functions entry points in bootloader
void (*boot_flash_page_erase_and_write)(unsigned long adr)=(void (*)(unsigned
long))(LAST_BOOT_ENTRY-12);
U8 (*boot_flash_read_sig) (unsigned long adr)=(U8 (*)(unsigned
long))(LAST_BOOT_ENTRY-10);
U8 (*boot_flash_read_fuse) (unsigned long adr)=(U8 (*)(unsigned
long))(LAST_BOOT_ENTRY-8);
void (*boot_flash_fill_temp_buffer) (unsigned int data,unsigned int adr)=(void
(*)(unsigned int, unsigned int))(LAST_BOOT_ENTRY-6);
void (*boot_flash_prg_page) (unsigned long adr)=(void (*)(unsigned
long))(LAST_BOOT_ENTRY-4);
void (*boot_flash_page_erase) (unsigned long adr)=(void (*)(unsigned
long))(LAST_BOOT_ENTRY-2);
void (*boot_lock_wr_bits) (unsigned char val)=(void (*)(unsigned
char))(LAST_BOOT_ENTRY);
// This function writes 0x55AA @ 0x1200 in the on-flash calling flash drivers located
in USB bootloader
void basic_flash_access(void)
{
unsigned long address;
unsigned int temp16;
temp16=0x55AA;
address=0x12000;
(*boot_flash_fill_temp_buffer)(temp16,address);
(*boot_flash_page_erase)(address);
(*boot_flash_prg_page)(address);
}
The full assembly code for the flash API drivers is given in “Appendix-B” on page 20.
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7. Using the USB bootloader for In System Programming
Flip software is the PC side application used to communicate with the USB bootloader (Flip is
available for free on the Atmel website).
For detailed instructions about using Flip and USB bootloader, please refer to AVR282: “USB
Firmware Upgrade for AT90USB” (doc 7769).
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8. Bootloader History
The following table shows the different bootloader revision and associated changes.
Table 8-1.
USB Bootloader History
Product
Bootloader Revision
Changes
1.0.1
Initial Revision
1.0.0
Initial Revision
1.0.1
Allow to use 16MHz cristal with 3.3V power supply and
CKDIV8 fuse.
1.0.5
Improved USB autobaud process
1.0.0
Initial Revision
AT90USB1287
AT90USB1286
AT90USB647
AT90USB646
AT90USB162
AT90USB82
ATmega32U4
ATmega16U4
9. Appendix-A
Table 9-1.
Summary of Frames from Host
Command Identifier
data[0]
data[1]
data[2]
data[3]
data[4]
Description
Id_prog_start
00h
01h
01h
Init EEPROM programming
00h
Display FLASH Data
Id_display_data
03h
Init FLASH programming
start_address
01h
end_address
start_address
end_address
02h
Display EEPROM Data
00h
Id_write_command
04h
FFh
Full chip Erase (bits at FFh)
00h
Hardware reset
03h
01h
00h
Id_read_command
05h
Id_change _base
_address
06h
Blank Check in FLASH
01h
03h
address
LJMP address
00h
Read Bootloader Version
01h
Read Device boot ID1
02h
Read Device boot ID2
30h
Read Manufacturer Code
31h
Read Family Code
60h
Read Product Name
61h
Read Product Revision
00
“PP”
Select “PP” 64kBytes flash
page number
18
7618C–AVR–07/08
Table 9-2.
DFU Class-specific Requests
bmRequestType
bRequest
wValue
wIndex
wLength
Data
0010 0001b
DFU_DETACH (0)
wTimeout
Interface (4)
Zero
none
0010 0001b
DFU_DNLOAD (1)
wBlock
Interface (4)
Length
Firmware
1010 0001b
DFU_UPLOAD (2)
wBlock
Interface (4)
Length
Firmware
1010 0001b
DFU_GETSTATUS (3)
Zero
Interface (4)
6
Status
0010 0001b
DFU_CLRSTATUS (4)
Zero
Interface (4)
Zero
none
1010 0001b
DFU_GETSTATE (5)
Zero
Interface (4)
1
State
0010 0001b
DFU_ABORT (6)
Zero
Interface (4)
Zero
none
19
7618C–AVR–07/08
10. Appendix-B
;*A************************************************************************
**
; $RCSfile: flash_boot_drv.s90,v $
;--------------------------------------------------------------------------; Copyright (c) Atmel.
;--------------------------------------------------------------------------; RELEASE:
$Name:
; REVISION:
$Revision: 1.7 $
$
; FILE_CVSID:
$Id: flash_boot_drv.s90,v 1.7 2005/10/03 15:50:12 $
;--------------------------------------------------------------------------; PURPOSE:
; This file contains the low level driver for the flash access
;**************************************************************************
**
NAMEflash_drv(16)
;_____ I N C L U D E S
______________________________________________________
#define ASM_INCLUDE
#include "config.h"
;**************************************************************************
**
; This is the absolute table entry points for low level flash drivers
; This table defines the entry points that can be called
; from the application section to perform on-chip flash operations:
;
;
;
entry_flash_page_erase_and_write:
R18:17:R16: The byte address of the page
;
;
entry_flash_fill_temp_buffer:
;
data16 :
R16/R17: word to load in the temporary buffer.
;
address:
R18/R19: address of the word in the temp. buffer.
;
;
;
entry_flash_prg_page:
R18:17:R16: The byte address of the page
;
;
;
entry_flash_page_erase:
R18:17:R16: The byte address of the page
;
;**************************************************************************
**
ASEG FLASH_END-0x0001B
entry_flash_page_erase_and_write:
20
7618C–AVR–07/08
JMP flash_page_erase_and_write
entry_flash_read_sig:
JMP
flash_read_sig
entry_flash_read_fuse:
JMP
flash_read_fuse
entry_flash_fill_temp_buffer:
JMP
flash_fill_temp_buffer
entry_flash_prg_page:
JMP
flash_prg_page
entry_flash_page_erase:
JMP
flash_page_erase_public
entry_lock_wr_bits:
JMP
lock_wr_bits
RSEGBOOT
;*F************************************************************************
**
; NAME: flash_page_erase_and_write
;--------------------------------------------------------------------------; PARAMS:
R18:17:R16: The byte address of the page
;--------------------------------------------------------------------------; PURPOSE: This function can be called for the user appplication
; This function performs an erase operation of the selected target page and
; the launch the prog sequence of the same target page.
; This function allows to save the 256 bytes software temporary buffer in
; the application section
;**************************************************************************
**
flash_page_erase_and_write:
PUSH
R18
RCALL flash_page_erase
POP
R18
RCALL flash_prg_page
RET
;*F************************************************************************
**
; NAME: flash_prg_page
;--------------------------------------------------------------------------; PARAMS: R18:17:R16: The byte address of the page
;--------------------------------------------------------------------------; PURPOSE:
Launch the prog sequence of the target page
21
7618C–AVR–07/08
;**************************************************************************
**
flash_prg_page:
RCALL
WAIT_SPMEN
MOV
R31,R17
MOV
R30,R16
OUT
RAMPZ, R18
LDI
R20,$05
;Wait for SPMEN flag cleared
;move adress to z pointer (R31=ZH R30=ZL)
;(1<<PGWRT) + (1<<SPMEN))
OUT SPMCSR,R20; argument 2 decides function (r18)
SPM
;Store program memory
RCALL
WAIT_SPMEN
RCALL
;Wait for SPMEN flag cleared
flash_rww_enable
RET
;*F************************************************************************
**
; NAME: flash_page_erase
;--------------------------------------------------------------------------; PARAMS:
R18:17:R16: The byte address of the page
;--------------------------------------------------------------------------; PURPOSE:
Launch the erase sequence of the target page
;--------------------------------------------------------------------------; NOTE:
not
This function does nt set the RWWSE bit after erase. Thus it does
; erase the hardware temporary temp buffer.
; This function is for bootloader usage
;--------------------------------------------------------------------------; REQUIREMENTS:
;**************************************************************************
**
flash_page_erase:
RCALL
WAIT_SPMEN
MOV
R31,R17
MOV
R30,R16
OUT
RAMPZ, R18
LDI
R20,$03
;Wait for SPMEN flag cleared
;move adress to z pointer (R31=ZH R30=ZL)
;(1<<PGERS) + (1<<SPMEN)))
OUT SPMCSR, R20; argument 2 decides function (r18)
SPM
;Store program memory
RCALL
WAIT_SPMEN
;Wait for SPMEN flag cleared
;RCALL
flash_rww_enable CAUTION DO NOT ACTIVATE HERE or
;
you will loose the entire page buffer content !!!
RET
22
7618C–AVR–07/08
;*F************************************************************************
**
; NAME: flash_page_erase_public
;--------------------------------------------------------------------------; PARAMS:
R18:17:R16: The byte address of the page
;--------------------------------------------------------------------------; PURPOSE:
Launch the erase sequence of the target page
;--------------------------------------------------------------------------; NOTE:
!!!!This function set the RWWSE bit after erase. Thus it
; erase the hardware temporary temp buffer after page erase
;**************************************************************************
**
flash_page_erase_public:
RCALL
WAIT_SPMEN
MOV
R31,R17
MOV
R30,R16
OUT
RAMPZ, R18
LDI
R20,$03
;Wait for SPMEN flag cleared
;move adress to z pointer (R31=ZH R30=ZL)
;(1<<PGERS) + (1<<SPMEN)))
OUTSPMCSR, R20; argument 2 decides function (r18)
SPM
RCALL
;Store program memory
WAIT_SPMEN
RCALL
;Wait for SPMEN flag cleared
flash_rww_enable
RET
;*F************************************************************************
**
; NAME: flash_rww_enable
;--------------------------------------------------------------------------; PARAMS:
none
;--------------------------------------------------------------------------; PURPOSE:
section
Set RWSE bit. It allows to execute code in the application
; after a flash prog (erase or write page)
;**************************************************************************
**
flash_rww_enable:
RCALL
WAIT_SPMEN
;Wait for SPMEN flag cleared
LDI
R20,$11
;(1<<WWSRE) + (1<<SPMEN)))
OUT SPMCSR, R20 ; argument 2 decides function (r18)
SPM
RJMP
;Store program memory
WAIT_SPMEN
;Wait for SPMEN flag cleared
23
7618C–AVR–07/08
;*F************************************************************************
**
; NAME: flash_read_sig
;--------------------------------------------------------------------------; PARAMS:
; Return: R16: signature value
;--------------------------------------------------------------------------; PURPOSE:
addr
Read harware signature byte. THe byte is selected trought the
; passed as argument (see product data sheet)
;**************************************************************************
**
flash_read_sig:
RCALL
WAIT_SPMEN
MOV
R31,R17
MOV
R30,R16
OUT
RAMPZ, R18
LDI
R20,$21
;Wait for SPMEN flag cleared
;move adress to z pointer (R31=ZH R30=ZL)
;(1<<SPMEN) | (1<<SIGRD))
OUT SPMCSR, R20; argument 2 decides function (r18)
LPM
;Store program memory
MOV
R16, R0
RJMP
WAIT_SPMEN
;Store return value (1byte->R16 register)
;Wait for SPMEN flag cleared
;*F************************************************************************
**
; NAME: flash_read_fuse
;--------------------------------------------------------------------------; Return: R16: fuse value
;--------------------------------------------------------------------------; PURPOSE: Read fuse byte. The fuse byte is elected through the address
passed
; as argument (See product datasheet for addr value)
;**************************************************************************
**
flash_read_fuse:
RCALL
WAIT_SPMEN
MOV
R31,R17
MOV
R30,R16
OUT
RAMPZ, R18
LDI
R20,$09
;Wait for SPMEN flag cleared
;move adress to z pointer (R31=ZH R30=ZL)
;(1<<SPMEN) | (1<<BLBSET))
OUT SPMCSR, R20; argument 2 decides function (r18)
LPM
MOV
;Store program memory
R16, R0
;Store return value (1byte->R16 register)
24
7618C–AVR–07/08
RJMP
WAIT_SPMEN
;Wait for SPMEN flag cleared
/*F************************************************************************
**
* NAME: flash_fill_temp_buffer
*--------------------------------------------------------------------------* PARAMS:
* data16 :
R16/R17: word to load in the temporary buffer.
* address:
R18/R19: address of the word.
* return:
none
*--------------------------------------------------------------------------* PURPOSE:
* This function allows to load a word in the temporary flash buffer.
*--------------------------------------------------------------------------* EXAMPLE:
* fill_temp_buffer(data16, address);
*--------------------------------------------------------------------------* NOTE:
* the first paramater used the registers R16, R17
* The second parameter used the registers R18, R19
***************************************************************************
**/
flash_fill_temp_buffer:
MOV
R31,R19
MOV
R30,R18
;move adress to z pointer (R31=ZH R30=ZL)
MOV
R0,R17
MOV
R1,R16
LDI
R20,(1<<SPMEN)
;move data16 to reg 0 and 1
OUT SPMCSR, R20; r18 decides function
SPM
; Store program memory
RJMP
WAIT_SPMEN
; Wait for SPMEN flag cleared
;*F************************************************************************
**
; NAME: lock_wr_bits
;--------------------------------------------------------------------------; PARAMS:
R16: value to write
;--------------------------------------------------------------------------; PURPOSE:
;**************************************************************************
**
lock_wr_bits:
25
7618C–AVR–07/08
RCALL
WAIT_SPMEN
MOV
R0,R16
; Wait for SPMEN flag cleared
LDI
R18,((1<<BLBSET)|(1<<SPMEN))
OUT SPMCSR, R18 ; r18 decides function
SPM
; write lockbits
RJMP
WAIT_SPMEN
; Wait for SPMEN flag cleared
;*F************************************************************************
**
; NAME: wait_spmen
;--------------------------------------------------------------------------; PARAMS:
none
;--------------------------------------------------------------------------; PURPOSE:
Performs an active wait on SPME flag
;**************************************************************************
**
WAIT_SPMEN:
MOVR0, R18
INR18, SPMCSR
; get SPMCR into r18
SBRC
R18,SPMEN
RJMP
WAIT_SPMEN
; Wait for SPMEN flag cleared
MOVR18, R0
RET
END
26
7618C–AVR–07/08
11. Document Revision History
11.1
7618B 03/08
1. Removed references to DFU Functional Descriptor throughout the document.
11.2
7618C 07/08
1. Update for AT90USB162/82, AT90USB64x, ATmega32U4 and ATmega16U4.
2. Update bootloader revision history.
27
7618C–AVR–07/08
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7618C–AVR–07/08