33970 Datasheet, PDF (12/36 Pages) Freescale Semiconductor, Inc – Dual Gauge Driver Integrated Circuit with Improved Damping Algorithms

FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
SPI PROTOCOL DESCRIPTION
The SPI interface has a full-duplex, three-wire
synchronous, 16-bit serial synchronous interface data
transfer and four I/O lines associated with it: Chip Select (CS),
Serial Clock (SCLK), Serial Input (SI), and Serial Output
(SO). The SI/SO pins of the 33970 follow a first in/first out
(D15/D0) protocol with both input and output words
transferring the most significant bit first. All inputs are
compatible with 5.0 V CMOS logic levels.
LOGIC COMMANDS AND REGISTERS
This section provides a description of the 33970 SPI behavior. To follow the explanations below, refer to Table 5 and to the
timing diagrams shown in Figure 6 and Figure 7.
Table 5. Data Transfer Timing
Pin
CS (1-to-0)
CS (0-to-1)
SO
SI
Description
SO pin is enabled.
33970 configuration and desired output states are transferred and executed according to the data in
the Shift registers.
Will change state on the rising edge of the SCLK pin signal.
Will accept data on the falling edge of the SCLK pin signal.
CS
SCLK
SI
D15 D14 D13 D12 D11 D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
SO
OD15 OD14 OD13 OD12 OD11 OD10 OD9 OD8 OD7 OD6 OD5 OD4 OD3 OD2 OD1 OD0
Output shift register is loaded here.
Note SO is tri-stated when CS is logic [1].
Figure 6. Single 16-Bit Word SPI Communication
CS
SCLK
SI
SO
D15 D14 D13 D12 D11
D2
D1
D0 D15* D14* D13* D4
D3
D2*
D1*
D0*
OD15 OD14 OD13 OD12 OD11 OD2 OD1 OD0 D15
D14
D13 OD4 OD3
D2
D1
D0
Notes
1. SO is tri-stated when CS is logic [1].
2. D15, D14, D13, ..., and D0 refer to the first 16 bits of data into the 33970.
3. D15*, D14*, D13*, ..., and D0* refer to the most recent entry of program data into the 33970.
4. OD15, OD14, OD13, ..., and OD0 refer to the first 16 bits of fault and status data out of the 33970.
Figure 7. Multiple 16-Bit Word SPI Communication
33970
12
Analog Integrated Circuit Device Data
Freescale Semiconductor