Datasheet

Seite 14
Ausgabe 08/2008 Technische Änderungen v orbehalten! HYGROSENS INSTRUMENTS GmbH Postf ach 1054 D-79839 Löf f ingen Tel: [phone] Fax: [phone]
SERIAL DIGITAL INTERFACE
4 Interface Commands
All implemented commands are available in all communication modes – I
2
C and SPI.
A received valid command interrupts the internal micro-controller and initiates the
processing of a command routine.
Com-
mand
(HEX)
Data Command Remarks Processing
time
System clock
2MHz
01 START_CYC_EEP Start measurement cycle including initialization from
EEPROM
350µs
02 START_CYC_RAM Start measurement cycle including initialization from
RAM
220µs
10 .. 1F READ_RAM0 Read data from RAM address 00 .. 0F
Writes data from RAM to SIF Output Registers
Usually followed by Read operation
50µs
20 .. 2F READ_RAM1 Read data from RAM address 10 .. 1F
Writes data from RAM to SIF Output Register
Usually followed by Read operation
50µs
30 .. 3F READ_EEP0 Read data from EEPROM address
00 .. 0F
Writes data from EEPROM to SIF Output Register
Usually followed by Read operation
50µs
40 .. 4F READ_EEP1 Read data from EEPROM address
10 .. 1F
Writes data from EEPROM to SIF Output Register
Usually followed by Read operation
50µs
5*-commands do not change EEPROM or RAM configuration, used for communication to devices with unknown
configuration
50 CFG_SIF_TO_OWI Configure SIF to Communication Mode OWI
50µs
51
55
59
5D
CFG_SIF_TO_SPI Configure SIF to Communication Mode SPI
51 SET_SIF_2_SPI SPI (CKE = 0, CKP = 0)
55 SET_SIF_2_SPI SPI (CKE = 0, CKP = 1)
59 SET_SIF_2_SPI SPI (CKE = 1, CKP = 0)
5D SET_SIF_2_SPI SPI (CKE = 1, CKP = 1)
50µs
52 CFG_SIF_TO_I2C Configure SIF to Communication Mode I
2
C
60 2 Byte SET_DAC Set Output DAC to value defined by data bytes
[0x0 … 0x7FF]
100µs
70 START_OM Start Open Mode
In Open Mode the command set is restricted!
Change to Command Mode is possible
50µs
71 START_NOM Start Normal Operation Mode (NOM)
In Normal Operation Mode the command set is
restricted!
Change to Command Mode or Open Mode is NOT
possible
72 START_CM Start Command Mode (CM)
Complete command set!
Change to Open Mode or Normal Operation Mode is
possible
Table 2: Restricted command set for serial digital interface – commands are always valid
During processing time the digital serial interface (SIF) is disabled, transmitted
commands are ignored. The processing time depends from the internal system clock
frequency, which is usually 2MHz but is changeable by EEPROM programming. The
commands are divided in two sets with different validity. Commands, which change
the configuration of the device, are ignored in NOM and are available only after
changing to CM.