From 4d5ac6cd5ba6b141efb0f16e254d15f4fe333c29 Mon Sep 17 00:00:00 2001 From: Leah Rowe Date: Sat, 16 Oct 2021 09:10:52 +0100 Subject: [PATCH] docs/install/spi: note about wp/hold pins on ch341a --- site/docs/install/spi.md | 2 ++ 1 file changed, 2 insertions(+) diff --git a/site/docs/install/spi.md b/site/docs/install/spi.md index ab0d2bc..7e36834 100644 --- a/site/docs/install/spi.md +++ b/site/docs/install/spi.md @@ -52,6 +52,8 @@ In practise, most people will not fix their ch341a and instead just risk it, so no documentation will be provided for ch341a on this website. It is best to discourage use of that device. +**Not covered on that eevblog page: the WP/HOLD pins (pins 3 and 7) must be held high via pull-up resistors, but on CH341A dongles, they are directly connected to 3.3V DC (continuity with pin 8). It is advisable to cut these two connections, to the WP and HOLD pins, and jump the cuts using pull-up resistors instead. A value between 1k to 10k (ohms) should be fine.** + In case it's not clear: Please do not buy the ch341a! It is incorrectly engineered for the purpose of