Tamson Instruments bv
Page
9/22
Van ’t Hoffstraat 12
2665 JL Bleiswijk, The Netherlands
T. 31 (0) 10 522 43 73
E20 Thermometer man.docx Rev. 3.03 UK 0319
E-mail: [email protected]
Website: www.tamson.com
VAT: NL 80 66 34 984 B01
Bank account no.:
NL28 INGB 0007 350 370
NL95 RABO 0160100046
Chamber of commerce 27 16 95 41
ISO 9001 : 2015
NL/PRO 238239125
8.4 Protocol
'Byte 1 Synchronisation, decimal 84 (this is a fixed
character)
'Byte 2 Length of package, 7..255.
Each package needs a minimum of 6 bytes
These 6 bytes are the so called overhead:
Byte1,2,3,4,5,7
A package is formed by these six bytes plus
additional data.
'Byte 3 Command
bit 0
0 = data read
1 = data write
bit 1 and 2
00 = not used
01 = Location is SRAM
10 = Location is FLASH
11 = Location is external EEPROM
'bit 3
0 = No extra routine
1 = Set Real Time Clock
'Byte 4 Address high byte
'Byte 5 Address low byte
'Byte 6 Data, the actual information - 1 to 248 bytes
'Byte 7 Checksum, all data is added, last two hex are used.
I.e. a value of &h 30D returns 0D as checksum.
8.5 Send and receive
In order to receive the actual temperature from the E20
thermometer following hex code must be send to the
thermometer:
54 0A 02 01 77 00 00 00 00
D8
(The red value "D9" is the checksum)
Now assume the thermometer reads 25.147°C, than the
response from the thermometer will be:
54 0A 02 01 77
63 2D C9 41
72
In
Red
the checksum
In
Green
the temperature indicated in hexadecimal
Please note that the LSB is send first whilst the MSB is last.
So the data must be swapped:
41 C9 2D 63