Data Sheet TLE 7230 R

V2.0

Page

2005-10-05

8

CS – Chip Select of the Serial Peripheral Interface

SO – Signal Output of the Serial Peripheral Interface

SI – Signal Input of the Serial Peripheral Interface. The pin has an internal pull down structure.

SCLK – Clock Input of the Serial Peripheral Interface. The pin has an internal pull down structure

SPI

The SPI is a Serial Peripheral Interface with 4 digital pins

and a 16 bit shift register. The SPI is used to configure and

program the device, turn on and off channels and to read

detailed diagnostic information.

SPI Signal Description:

CS - Chip Select. The system microcontroller selects the TLE 7230 R by means of the CS pin. When-

ever the pin is in a logic low state, data can be exchanged between the µC and TLE 7230 R.

CS = H: Any signals at the SCLK and SI

pins are ignored and SO is forced into a

high impedance state.

CS = H

àL:

• diagnostic information is transferred

from the diagnosis register into the SPI

shift register. (in sleep mode no trans-

fer of diagnostic information)

• serial input data can be clocked into

the SPI shift register from then on

• SO changes from high impedance

state to logic high or low state corre-

sponding to the SO bits

CS = L: SPI functions as a shift register. With each clock signal at the SCLK pin the state of the SI is

read into the SPI shift-register (falling clock edge) and one diagnosis bit is written out of SO (rising

edge).

CS = L

àH:

• transfer of SI bits from SPI shift register into the internal logic registers sent command is valid

• reset of diagnosis register if sent command is valid

To avoid any false clocking the serial clock input pin SCLK should be logic low state during high to low

transition of CS. The SPI of the TLE 7230 R has an integrated modulo 8 counter. If the number of clock

signals is not an integer multiple of 8 the SPI will not accept the data in the shift register and the fault

register will not be reset.

SCLK - Serial Clock. The serial clock pin clocks the internal SPI shift register of the TLE 7230 R. The

serial input (SI) accepts data into the input SPI shift register on the falling edge while the serial output

(SO) shifts diagnostic information out of the SPI shift register on the rising edge of serial clock. It is es-

sential that the SCLK pin is in a logic low state whenever chip select (CS) makes any transition.

internal logic registers

diagnosis register

16 bit SPI shift register

SI

SO

CS

CS

MSB

MSB

LSB

LSB

Serial input

data MSB first

Serial output

(diagnosis)

data

MSB first

SPI

CS

SCLK

SI

SO