The Problem

In Issue #4, a problem with verifying LGT8F328P-SSOP20 boards was encountered. Programmers based on the FTDI chip can program (write and verify) and verify boards. Using a CH341 based USB to serial converter board could write, but not verify.

Using a CH340E (aka BTE17-06) usb-serial adapter, similar symptoms and many instabilities were described in Issue #54, with both LGT8F328P MiniEVB-SSOP20 and MiniEVB-LQFP32 boards. The uploaded sketch was often corrupted, and the board was starting running the sketch before AVRDUDE was finished verifying the data. Problem was solved when replacing CH340E with a CP210x usb-serial adapter.

The Investigation

Captures of the programming transaction were captured. They show signifigant timing differences between the FTDI and CH341 converters.

The Data

Put links to the capture files here. Also add a few images of Pulseview screens.

The Resolution

Let's hope we come up with something.