ST75951 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'ST75951' PDF : 21 Pages View PDF
FUNCTIONAL DESCRIPTION (continued)
Figure 21
ST75951
AUXIN 41
D3 31
D4 30
RING 15
D1 35
D2 34
HIGH
PASS
FILTER
F0 or F0/2
LOW
PASS
FILTER
Bit DR
DETECTOR
MUX
F0 or F0/2
ATTENUATION
0dB/6dB/Infinite
MUX
GAIN
ANALOG
MODULATOR
DAC 1 BIT
FIRST ORDER
DIFFERENTIAL
SWITCHED
CAPACITOR FILTER
10 - Host Interface
Table 3
HC1 HC0 LSB 2nd FS
000
no
001
yes
01x
no
1
x
x
yes
Mode Description
Software mode,
data transfer only
Software mode,
data xfer + control xfer
Hardware mode,
data transfer only
Hardware mode,
data + control transfer
The host interface is a Serial Synchronous Inter-
face (FS, SCLK, DOUT, DIN).
Two modes of serial transfer are available and are
selected via pins HC0 and HC1.
First mode is a software mode control (15 bits
transmit data and 16 bits receive data). In this mode
ST75951 is completely controlled through the SSI,
the access of control register is done by managing
the LSB of the transmit data word.
Figure 22 : WRITE REG n , READ default REG 2
Second mode is a hardware mode control (16bits
data transmit and receive). In this mode the access
of control register is done via dynamic setting of
Pins HC0 and HC1 (see Table 3).
The bit 15 of the control word is used to do a read
only or a read and write of control register
(bit 15 = 1 Read only, bit 15 = 0 Read & Write).
11 - Control Registers
This section defines how to handle the 4 registers
implemented in ST75951.
11.1 - Write / Read Operation (D15 = 0)
This is a one sampling frequency period duration
operation, where the 16-bit word sent from the host
on DIN, contains the write qualifier, the address
register and the data field.
Contemporaly ST75951 ouptuts on DOUT the
register 2 value (GPIO) (see Figure 22).
1/2 Sampling Period
Sampling Period
FS
D15
DI
DATA WORD INPUT
0
@regN+cont.word
D0
HC0
HC1
DATA WORD OUTPUT
10
REGISTER 2 VALUE
01
13/21
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