iC-MB3

BiSS INTERFACE MASTER, 1-Chan./3-Slaves

Rev D1, Page 21/26

The sensor chain can be initiated using the command INIT. A set REG bit starts the transmission of register data

between iC-MB3 and a sensor.

The transmission of sensor data can be triggered via bits GETSENS0 and GETSENS1. In both instances a new

transmission process is initiated; the difference between the two commands lies in how the transmission cycle is

ended. With GETSENS0 the cycle finishes with a high; GETSENS1 ends on a low.

When initializing the sensor data transmission via GETSENS0 = 1 and GETSENS1 = 1, the cycle finishes with a

level determined by the REG bit entered (Address 243, bit 6), i.e. for REG = 0 with a high or for REG = 1 with a

low. By this function register data can be transmitted to slaves operating on the BiSS protocol model C principle

in parallel to the transmission of sensor data (see "Transmission of register data in sensor mode").

If an AGS bit has been set sensor data is read in cyclically according to the cycle frequency set in register 232

(FREQAGS) without any further commands being issued by the controller.

Registers start address (REGADR, address 226), number of bytes (REGNUM, address 227) and slave ID

(SLAVEID, address 229) stipulate from which slave register address onwards how many bytes are to be written

to or read out from which specific slave. A byte count of 0 entered for REGNUM signals the transmission of a

single register value; a 31 indicates the transmission of 32 register values. In the register REGBYTES (address

243) a 0 is entered if communication has proved error free. In the event of error the number of registers correctly

read or written is displayed.

iC-MB3 does not support autonomous register communication as with BiSS C.Mode protocol, thus it is imperative

that address 229's bit REGVERS remain set to 0.