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HTerm cannot connect to KitProg3 COM Port after KitProg3 firmware update

HTerm cannot connect to KitProg3 COM Port after KitProg3 firmware update

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What is the workaround for the connection issue between HTerm  and KitProg3 COM port after the KitProg3 firmware update?


After updating the KitProg3 firmware version to 2.21.1005, the HTerm tool, which is a serial terminal, fails to connect to the KitProg3/MiniProg4 COM Port. The following error message appears: “OpenPort::Baudrate Value not supported” (see Figure 1). However, in other serial terminals like Tera Term, the connection is established with the same baud rate settings.

Figure 1. HTerm error on Connect

Figure 1. HTerm error on Connect.PNG

This error occurs because starting from KitProg3 firmware version 2.21, KitProg3 returns the actual baud rate at which the UART operates that differs slightly from the standard UART baud rates that we set in the serial terminal tool. HTerm compares the baud rate set and the baud rate returned by the KitProg3 device. So, in the case of HTerm, the baud rate set, for example, 115200 does not match with the baud rate returned by KitProg3, 115384. However, this comparison is not done in other serial terminal tools which is why the COM port gets connected without any issue.

Workaround for HTerm  and KitProg3 COM port


1. Set the actual KitProg3 UART baud rate in HTerm. You can calculate the actual baud rate by following these steps:

Divider=(Master Clock)/(COM Port baud rate)

2. If in case the divider is a decimal, round it off to the nearest integer. For example, in the case of 115200:             


3. After calculating the divider, calculate the actual baud rate:

- Actual baud rate=(Master Clock)/Divider

- Actual baud rate=24MHz/208 ≈115384

4. Some of the common baud rates are mentioned in the following table:

COM Port baud rate

KitProg3 UART baud rate
















5. After setting the actual KitProg3 UART baud rate in the HTerm tool, the tool connects to the COM port without an error as shown in Figure 2.

Figure 2. COM Port connected

Figure 2. COM Port connected.PNG