Host Protocols Direct Protocol DFU class GET CONTEXT
April 13, 2023 at 2:39 AMDFU GET_CONTEXT
Role
Read the characteristic’s of the bootloader and of the DFU implementation in the device.
Command
| Field | Value |
|---|---|
| CLA | 5D (DFU) |
| INS | 01 |
| Data | None |
Response
| Byte | Name | Description |
|---|---|---|
| 0 | SUCCESS | |
| 1 | Timeout | How many seconds will the bootloader stay in rescue mode before trying to boot the firmware |
| 2 | Version | Version of the DFU protocol (0, 1 or 2) |
| 3-4 | Flags | Flags set by the bootloader after hardware detection |
| 5-2 | CPU Name | ASCII string with the MCU family (“RX65x”, “RX11x”, “SAMD5x”…) |
| 13-16 | ROM Start | Address of first writable byte in MCU’s internal ROM |
| 17-20 | ROM End | Address of last writable byte in MCU’s internal ROM |
| 21- xx | Flash ID | ID string of the SPI flash (NVM) |
Flags
| Bit | Name | Description |
|---|---|---|
| 12-15 | RFU | |
| 11 | has_expram | RX65x family:0: MCU has 1MB ROM and 256kB RAM1: MCU has 2MB ROM and 512kB RAMOther MCU families: RFU |
| 10 | has_aes_prng | 0: No crypto engine1: The device’s MCU features a crypto engine that provides AES HW & PRNG HW |
| 9 | has_network | 0: No network interface1: The device features a network interface (Ethernet) |
| 8 | has_usb | 0: No USB interface1: The device features a USB interface |
| 7 | has_battery | 0: No battery charger detected1: The device features a battery charger (and therefore is likely to have a battery) |
| 6 | in_bootloader | 0: The firmware is running1: The bootloader is running (rescue mode) |
| 5 | just_flashed | 0: The firmware has not been changed since last reset1: The bootloader has just rewritten the MCU’s internal ROM |
| 4 | has_vegas | 0: No ‘Vegas’ antenna detected1: A ‘Vegas’-compliant antenna has been detected on the I2C bus |
| 3 | has_storage | 0: No SPI flash detected1: A SPI flash has been detected (the Flash ID string is following) |
| 2 | force_rescue | 0: The device is not forced in rescue mode1: The device is forced in rescue mode, the bootloader will not start the firmware |
| 1 | cold_reset | 0: Last boot reason is warm reset (software reset or reset button)1: Last boot reason is cold reset (power on) |
| 0 | is_present | 0: RFU1: Bootloader flags are valid |
Flash ID
The size of the answer is either 0 bytes long (no SPI Flash detected) or longer (SPI Flash detected).
Depending on the presence or not of the SPI Flash, the DFU protocol shall allow to perform a direct DFU/ROM rewriting using PUSH_TO_ROM instead of using the SPI flash storage (NVM) to store the new firmware using PUSH_TO_STORAGE or PUSH_TO_STORAGE_FAST.
Example for an MT25QL128 flash: 20 BA 18 10 40 00 2E 20 85 00 10 0E 00 2E 00 B6 08 BA A4 AA