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.

See EXTECH 407760/Beagle_dump for more details on protocol

Hardware

Device:

• Main CPU: TBD
• TBD: CEM DT-173
• TBD
• TBD
• TBD
• Battery: 3.6v 1/2 AA battery

it's hard to read the chip numbers

There's two chips on this side of the board. Same markings on both


They have the TI logo
TI 062C
15K
CV8J

USB cable:

• TBD

Photos

Device:

• Extech 407760.jpg
• 
• 

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.