Summary of CH3330N – Small and Cheap USB-Serial Converter IC Needs No Crystal
The Air602 is a low-cost ARM WiFi module competing with the ESP8266, notable for integrating the WCH CH330N USB-to-Serial chip. This chip features an 8-pin SOP8 package, a built-in crystal oscillator, and driver compatibility with the popular CH340. It supports baud rates from 50 bps to 2 Mbps while requiring fewer external components than its predecessor.
Parts used in the Air602 Project:
- Air602 low-cost ARM WiFi module
- WCH CH330N USB to Serial Chip
- USB (Universal Serial Bus) interface
- UART (Universal Asynchronous Receiver Transmitter) peripheral
- Built-in crystal oscillator
- External components
Recently the hobbyist market has seen the appearance of the Air602 low-cost ARM WiFi module. This module might be a potential competitor of ESP8266, another low-cost powerful WiFi module, that took the electronics hobbyists by storm long ago and is still extremely popular. But what’s more interesting about the Air602 module is the usage of a completely new USB to Serial Chip – WCH CH330N. This chip has features similar to CH340, but fewer pins (e.g. DTS, and CTS are missing), and available in a tiny SOP8 package.
Here is a brief explanation about USB to Serial chip and what is its usage. A USB to Serial converter converts USB (Universal Serial Bus) signal to UART (Universal Asynchronous Receiver Transmitter) signal and vice-versa. Most 8-bit and 16-bit low-cost microcontrollers do not feature built-in USB stack, rather they have UART peripheral. So, in order to establish communication between a PC that features USB and a microcontroller that only has UART, a converter is used.
CH330N is catching the attention of tinkerers for its small 8-pin-only form factor, built-in crystal oscillator, and compatibility with CH340 drivers. The CH340 (or CH340G) is yet another USB to Serial converter IC that has been popular for a long period of time. It has a higher pin count compared to CH330N and also supports CTS and DTS, but requires external oscillator circuitry in order to work. The CH330N, on the other hand, is way cheaper than the CH340 and requires only a few external components. This USB to Serial converter supports baud rate from 50 bps to 2 Mbps. The following schematic diagram shows the application of CH330,
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What is the primary function of the Air602 module?
The Air602 is a low-cost ARM WiFi module that serves as a potential competitor to the ESP8266. -
Which specific USB to Serial chip does the Air602 use?
The Air602 uses the completely new WCH CH330N USB to Serial chip. -
How does the CH330N differ from the CH340 regarding pin count?
The CH330N has fewer pins than the CH340 because it lacks DTS and CTS signals. -
Does the CH330N require an external crystal oscillator circuit?
No, the CH330N includes a built-in crystal oscillator and requires only a few external components. -
What baud rate range does the CH330N support?
The converter supports baud rates ranging from 50 bps to 2 Mbps. -
Is the CH330N compatible with drivers designed for the CH340?
Yes, the CH330N offers compatibility with CH340 drivers.
