HC11 basic commands

Quick n dirty screen cap of a Cool Term session running thru basic AT commands for an HC11 433MHz wireless UART, the serial port connections used for the session are displayed at the end of the video and listed below

Serial adapter used was a small CH340G module set to 3.3V

CHG RX to HC11 TX
CHG TX to HC11 RX
CHG VC to HC11 VCC
CHG GND to HC11 GND
and CHG GND to HC11 SET (in order to put the HC11 into command mode)

I tied HC11SET (Pin 5) to GND before powering on module, but works equally well if you pull it to GND whilst module is running (which is a bit bit more useful if wired to a microcontroller and you want to have a subroutine that asserts the SET pin, sets module parameters and then removes the SET again)

serial connection parameters used in this session to talk to the module:

baud rate 9600
data bits 8
parity N
stop bits 1

Flow control was set to XON
DTR and DTS were set to OFF

Terminal mode was set to line mode
Enter key emulation was CR+LF
Local echo was ON

Coolterms receive and transmit options were all left off

the HC11 basic command set is as follows (all commands are upper case, the module will ignore lowercase commands)

CONFIRM MODULE READY: AT
GET MODULE VERSION: AT+V
RETURN ALL PARAMETERS: AT+RX
SET BAUD RATE: +Bxxxxx where xxxxx is desired rate eg AT+B19200
SET CHANNEL: AT+Cxxx where xxx is channel number e.g. AT+C003
SET ADDRESS: AT+Axxx where xxx is address e.g AT+A002
SET POWER: AT+Px where x is desired level e.g AT+P7

RESTORE MODULE TO DEFAULTS: AT+RESET

full comand set -what each power level corresponds to, changing modes etc is available from here

likewise using the module in 'alternative mode' is also covered in that document (like an XBEE S1, the HC11 can be set so that instead of being used as a serial UART, the TX RX and SET pins on module A can be used as inputs for wireless i/o - with their current High/LOW status reflected in the output of corresponding pins on module B)

Anyways, hopefully above will provide a wee bit of getting you started help for folks when it comes to the HC11

[BMEmbeddedSolutions]

Thanks for the video, very helpful for a beginner.