DS_1x22_017
73M1822/73M1922 Data Sheet
8.7 MAFE Configuration Registers
The 73M1x22 allows MAFE control frame generation via software control or automatically by the hardware.
Using the software-controlled control frame, host resources can be saved by removing the redundant
control frame generated by the hardware control.
Function
Mnemonic Location
Register
Type Description
SPOS
HC
0x02[1]
0x02[0]
W
W
SPOS
0 = Control frames occur half way between data frames. (Default)
1 = Control frames occur after one quarter of the time between data
frames has elapsed.
Hardware Controlled Control Frame Enable
0 = Control frame is under host software control, the lsb of SDIN data
stream becomes a control frame request bit and control frames
happen only on request. The actual value of bit 0 of SDIN data stream
is forced to 0. (Default)
1 = Control frame generation is under hardware control, bit 0 of SDIN
data stream becomes bit 0 of the transmit word and control frames
occur automatically after every data frame.
8.8 Slave Registers
The 73M1x22 allows a daisy chain of up to seven slave devices on the same bus. In this configuration, only
one device on the bus can be a master and the rest are slaves.
Function
Mnemonic Location
Register
Type Description
DSYEN
0x01[7]
W
Daisy Chain Configuration Enable
0 = Disable Daisy Chain.
1 = Enable Daisy Chain.
NSLAVE
0x01[6:4]
W
Number of Slaves in Daisy Chain Mode
Specifies the number of slaves supported. The maximum number is
7. There are two default values. The default in Master Mode is 000.
The default in Slave Mode is 001.
MSIDEN
MSID
0x01[3]
0x01[2]
W
W
Master/Slave Identification Enable
When enabled in a daisy chain configuration, the MSID control bit
forces the least significant bit of the SDOUT data stream.
0 = MSID feature disabled.
1 = MSID feature enabled. (Default)
Master/Slave Identification
When MSIDEN = 1, in a daisy chain configuration (DSYEN = 1), this
bit allows selecting the value of bit 0 of the SDOUT data stream.
0 = The least significant bit of SDOUT is forced to 0.
1 = The least significant bit of SDOUT is forced to 1. (Default)
If DSYEN = 0, MSID has no impact on the least significant bit of the
SDOUT data stream. (Default)
SCK32
0x01[1]
W
Daisy Chain FSD Latency Control
0 = FS to FSD delay is 32 SCLK periods. (Default)
1 = FS to FSD delay is 16 SCLK periods. This bit must be set when
there are four or more slave devices.
When a master is driving a slave, only Early Type is allowed.
Rev. 1.6
51
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