[PATCH] doc/sipeed/maix: describe RESET and BOOT button

[Heinrich Schuchardt]

In the boot flow description add the RESET and BOOT button as well as the
function of the DTR and RTS lines of the serial interface.

Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
---
 doc/board/sipeed/maix.rst | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/doc/board/sipeed/maix.rst b/doc/board/sipeed/maix.rst
index 90ef70b7cf..a8efc90440 100644
--- a/doc/board/sipeed/maix.rst
+++ b/doc/board/sipeed/maix.rst
@@ -345,11 +345,15 @@ Technical Details
 Boot Sequence
 ^^^^^^^^^^^^^

-1. ``RESET`` pin is deasserted.
+1. ``RESET`` pin is deasserted. The pin is connected to the ``RESET`` button. It
+   can also be set to low via either the ``DTR`` or the ``RTS`` line of the
+   serial interface (depending on the board).
 2. Both harts begin executing at ``0x00001000``.
 3. Both harts jump to firmware at ``0x88000000``.
 4. One hart is chosen as a boot hart.
-5. Firmware reads value of pin ``IO_16`` (ISP).
+5. Firmware reads the value of pin ``IO_16`` (ISP). This pin is connected to the
+   ``BOOT`` button. The pin can equally be set to low via either the ``DTR`` or
+   ``RTS`` line of the serial interface (depending on the board).

    * If the pin is low, enter ISP mode. This mode allows loading data to ram,
      writing it to flash, and booting from specific addresses.
--
2.28.0