From f2b620d22f9328b13123d95ad6cffab74df2ec51 Mon Sep 17 00:00:00 2001
From: hanwckf <hanwckf@vip.qq.com>
Date: Sun, 27 Aug 2023 11:45:24 +0800
Subject: [PATCH] update readme.md

---
 README.md | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 6657161..f55afe6 100644
--- a/README.md
+++ b/README.md
@@ -16,13 +16,20 @@ A SPI-NAND flash programmer software botched together using SPI-MEM and SPI-NAND
 
 [WCH CH347](https://www.wch.cn/products/CH347.html)
 
-The default driver. No extra arguments needed. 
+The default driver.
+
+add the arguments to set CH347 SPI clock (KHz), default is 30000:
+
+```shell
+# set CH347 SPI clock to 15MHz
+-a 15000
+```
 
 [dword1511/stm32-vserprog](https://github.com/dword1511/stm32-vserprog)
 
 add the following arguments to select this driver:
 
-```
+```shell
 -d serprog -a /dev/ttyACM0
 ```