EXTECH 407760

EXTECH 407760

File:Extech 407760.jpg
Status	planned
Source code	tondaj-sl814
Connectivity	tbd
Frequency range	tbd
Measurement range (A)	tbd
Resolution	tbd
Accuracy (94dB@1kHz)	tbd
Frequency weighting	tbd
Time weighting	tbd
Website	extech407760.cn

The EXTECH 407760 is a sound level meter with USB connectivity.

See EXTECH 407760/Info for more details (such as lsusb -vvv output) about the device.

Hardware

Device:

• Main CPU: TBD
• TBD
• TBD
• TBD
• TBD

USB cable:

• TBD

Photos

Device:

USB cable:

TBD

Protocol

The device has a usb connector. The device accepts bulk transfer commands on a usb bus.

Commands / replies

407760(EXTECH) Communication Protocol 
Basic setup (64 byte in all, latter is 0)
0        1        2         3          4          5    6    7      8     9    10    11
LED	STATUS	Samprate	Alarm HI	Alarm Low	y	m	d	H	M	S	Samp points
10
20
30
0
	U8	U8	U8	U8	U8	U8	U8	U8	U8	U8	3U8

STATUS:
7	6	5	4	3
	2
 	  1         0

Auto：0
Manual：1			RT   1
STOR 0	1dBA
0dBC	1fast
0slow	S:01  
M:10
H:11
Samprate   
   0x01 represent  50ms
   0x02          500ms
   0x03          1s
   0x04          2s
   0x05          5s
   0x06          10s
   0x07          60s


Download the data
PC transmits the read-command 00,00,0D in read Mode. 

If the first byte of reply is 0XFF , then it is STOR MODE

{STOR MODE
2
 HI	  1
M	0
LOW
Transmit the read-command 00,00,0f READ data

READ INFO
11	10	9	8	7	6	5	4	3
	2
 	  1
	0


Alam
H
	
Alam
L
		
fs
	
unit
	
S
	
M	
H	
d	m m	
y	Samprate 


BLOCKBUF   512
Except the last time, It is sent BLOCKBUF real data 
2
 hi	  1
lo	0
0x0f
Hi*256+lo is the times of reading data
                      //STOR MODE


}
If it not 0XFF, then it is REAL MODE

STATUS
7	6	5	4	3
	2       1        0
  

Auto：0
Manual：1	RT/STOR	check	
1dBA
0dBC	11fast
0slow	Samprate

SAMPRATE =0 this means EMS memory is empty

“serial parameters”

To connect to the device via USB, you will need to know the following for development..


VID : 			VID_10C4
PID :			PID_0003
Baud rate :		(9600)
Bit value :		8

Notes

TBD

Python script

Here's a quick Python script for getting the values out of the EXTECH 407760. A sigrok driver will follow soon.

#!/bin/python

import usb.core import sys dev = usb.core.find(idVendor=0x10c4, idProduct=0xea61)

1. dev.baudrate=9600

dev.set_configuration() dev.reset()

bytes_written = dev.write(0x02, [0x00,0x00,0x0D], 0) print "_dbg bytes_written: ", bytes_written

for x in xrange(0,100):

 print "_dbg attempting read for the %d time\n" % x
 try:
   data = dev.read(0x82, 1,0,1000)
   if data:
     print "Data found!\n"
     sys.exit()
   else:
     print "Data not found!\n"
 except:
   pass

Example output:

TBD

Resources

TODO.