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[realtek-ambz] Improve flashing guide, add test pads for WR2 board (#147)

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* platform/realtek-ambz: Improve flashing guide

Known USB adapter compatibility issues. Emphasize, so that the paragraph is
easier to notice.

Signed-off-by: Pavel Fedin <pavel_fedin@mail.ru>

* base/wr2: Add UART2 test pads to the WR2 diagram

The module has UART2, necessary for flashing, only on test pads. Document this.

Signed-off-by: Pavel Fedin <pavel_fedin@mail.ru>

* Move test pads to separate files, update variants

* Update wiring guide

---------

Signed-off-by: Pavel Fedin <pavel_fedin@mail.ru>
Co-authored-by: Kuba Szczodrzyński <kuba@szczodrzynski.pl>
This commit is contained in:
Sonic-Amiga
2023-07-11 12:46:36 +03:00
committed by GitHub
parent f8876bba87
commit 6169f68119
11 changed files with 182 additions and 25 deletions
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19
docs/platform/realtek-ambz/flashing.md
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@@ -5,7 +5,12 @@
[Read chip docs](README.md){ .md-button }
</div>
Downloading is done using UART2 (sometimes called Log_UART). Refer to your board documentation to find the correct pins. You need a good USB<->UART adapter (preferably a real FT232RL) for the process.
Downloading is done using UART2 (sometimes called Log_UART). Refer to your board documentation to find the correct pins.
!!! tip
You need a good USB<->UART adapter for the process. Some chips may not support 1.5M baud rate,
required by the ROM for the initial handshake. Widespread PL2303 is currently known not to work,
at least under Windows. FT232RL is verified to work reliably.
**Read [Using ltchiptool](../../flashing/tools/ltchiptool.md) to learn the flashing procedure**
@@ -16,21 +21,23 @@ Downloading is done using UART2 (sometimes called Log_UART). Refer to your board
----|------------------------------
RX | TX2 (Log_TX / PA30)
TX | RX2 (Log_RX / PA29)
RTS | CEN (or RST, optional)
DTR | TX2 (Log_TX / PA30, optional)
GND | GND
Make sure to use a good 3.3V power supply, otherwise the adapter might
lose power during chip reset. Usually, the adapter's power regulator
is not enough and an external power supply is needed (like AMS1117).
If you didn't connect RTS and DTR, you need to put the chip in download
mode manually. This is done by connecting CEN to GND, while holding TX2 (Log_TX)
to GND as well. After doing that, you need to disconnect TX2 from GND.
You need to put the chip in download mode manually:
- connect CEN to GND
- connect TX2 to GND
- release CEN from GND
- release TX2 from GND
If the download mode is enabled, you'll see a few garbage characters
printed to the serial console every second.
!!! tip
Because the UART uploading code is programmed in the ROM of the chip, it can't be software-bricked, even if you damage the bootloader.