View source for Bouffalo ISP Protocol V1

This page describes Bouffalo ISP Protocol V1, which is ISP protocol used to run images, write images to Flash or program fuses via UART, USB, SDIO or JTAG.

It is integrated in [[:Category:BL602_Series|BL602]], [[:Category:BL702_Series|BL702]], [[:Category:BL602_Series|BL808]] and [[:Category:BL602_Series|BL616]] series of chips, although, every series have some improvements to this protocol.

List of available interfaces for specific chips:

{| class="wikitable" 
|-
! Chip
! UART
! USB
! SDIO
! JTAG
! SD Card
|-
| BL602 Series
| Yes
| No
| Yes
| ?
| No
|-
| BL702 Series
| Yes
| Yes
| No
| ?
| No
|-
| BL808C
| Yes
| Broken
| ?
| ?
| Broken?
|-
| BL808D
| Yes
| N/A
| ?
| ?
| N/A
|-
| BL606P
| Yes
| ?
| ?
| ?
| N/A
|-
| BL616 Series
| Yes
| Yes
| ?
| ?
| ?
|}

= Getting into ISP/BootROM mode =

{{Fmbox
 | type = system
 | text = Currently the BootROM is not explored enough, to know how exactly the boot process works within it, although, we will describe here already known and tested boot flows.
}}

Currently, there are two ways of getting into ISP mode, which we will describe in next sections:

== Via GPIO ==

Every chip using ISP Protocol V1 have ability to get into ISP mode by specifying voltage level on specific pin during boot time. This mechanism is implemented within BootROM code.

{{Collapse top|title=Example hardware layout|width=unset}}
Example is taken from BL602 Datasheet

[[File:Bl602_bootpin_layout.png]]
{{Collapse bottom}}

{| class="wikitable" 
|-
! Chip
! Pin
! ISP Mode when pin is
! Note
|-
| BL602 Series
| IO8
| High
| 
|-
| BL702 Series
| IO28
| High
| 
|-
| BL808 Series
| IO39
| High
| Multiplexed with QSPI D3 pin
|-
| BL616 Series
| IO2
| High
| 
|}

= Handshake =