CS4225 Datasheet, PDF (16/30 Pages) Cirrus Logic – Digital Audio Conversion System

CS4225
Note 1
Note 2
SDA
001
ADDR
AD3-0
R/W
ACK
DATA
1-8
ACK
DATA
1-8
ACK
SCL
Start
Stop
Note 1: The first 3 address bits for the CS4225 must be 001.
Note 2: If operation is a write, this byte contains the Memory Address Pointer, MAP.
Figure 7 - Control Port Timing, I²C^® Mode
low to write. The next 8 bits form the Memory
Address Pointer (MAP), which is set to the ad-
dress of the register that is to be updated. The
next 8 bits are the data which will be placed into
register designated by the MAP. During writes,
the CDOUT output stays in the Hi-Z state. It
may be externally pulled high or low with a
47kΩ resistor.
The CS4225 has a MAP auto increment capabil-
ity, enabled by the INCR bit in the MAP register.
If INCR is a zero, then the MAP will stay con-
stant for successive reads or writes. If INCR is
set to a 1, then MAP will auto increment after
each byte is read or written, allowing block reads
or writes of successive registers.
To read a register, the MAP has to be set to the
correct address by executing a partial write cycle
which finishes (CS high) immediately after the
MAP byte. The auto MAP increment bit (INCR)
may be set or not, as desired. To begin a read,
bring CS low, send out the chip address and set
the read/write bit (R/W) high. The next falling
edge of CCLK will clock out the MSB of the
addressed register (CDOUT will leave the high
impedance state). If the MAP auto increment bit
is set to 1, the data for successive registers will
appear consecutively.
I²C ^®Mode
In I²C^® mode, SDA is a bidirectional data line.
Data is clocked into and out of the part by the
clock, SCL, with the clock to data relationship as
shown in Figure 7. There is no CS pin. Pins
AD0, AD1, AD2, AD3 form the chip address.
The upper 3 bits of the 7 bit address field must
be 001. To communicate with a CS4225, the
LSBs of the chip address field, which is the first
byte sent to the CS4225, should match the set-
tings of the AD0, AD1, AD2, AD3 pins. The
eighth bit of the address bit is the R/W bit (high
for a read, low for a write). If the operation is a
write, the next byte is the Memory Address
Pointer which selects the register to be read or
written. If the operation is a read, the contents of
the register pointed to by the Memory Address
Pointer will be output. Setting the auto incre-
ment bit in MAP, allows successive reads or
writes of consecutive registers. Each byte is
separated by an acknowledge bit. Use of the I²C
bus^®compatible interface requires a license from
Philips. I²C bus^® is a registered trademark of
Philips Semiconductors.
Control Port Bit Definitions
All registers can be written and read back, ex-
cept the status report byte, which is read only.
See the following bit definition tables for bit as-
signment information.
16
DS86PP8