| #!/usr/bin/env python3 |
| |
| # Copyright 2021 The Chromium OS Authors. All rights reserved. |
| # Use of this source code is governed by a BSD-style license that can be |
| # found in the LICENSE file. |
| |
| """Initializes port B on the FT4232H. |
| |
| If we don't do this, then software resets performed by the MCU don't work |
| correctly. See b/197175065 for details. Note, this is not needed if you're |
| already using ./scripts/proto2-openocd or a similar script, since they already |
| initialize port B in order to program the device. |
| """ |
| |
| from pyftdi.gpio import GpioAsyncController |
| |
| |
| gpio = GpioAsyncController() |
| # Note, it doesn't seem to matter which pins you set as inputs and output, nor |
| # whether you set outputs high or low, it still results in software resets |
| # working. Somewhat arbitrarily though, we enable the level shifter and set the |
| # SWD output pins low. |
| gpio.configure('ftdi://ftdi:ft4232/2', direction=0b100011, initial=0b100000) |
