Cirrus Logic CS8420 - Manual (Page 55)

DS245F4 55
CS8420
13. HARDWARE MODES
13.1 Overall Description
The CS8420 has six Hardware modes, which allow use of the device without using a micro-controller to ac-
cess the device control registers and CS & U data. The flexibility of the CS8420 is necessarily limited in
Hardware mode. Various pins change function in Hardware mode, and various data paths are also possible.
These alternatives are identified by Hardware mode numbers 1 through 6. The following sections describe
the data flows and pin definitions for each Hardware mode.
13.1.1 Hardware Mode Definitions
Hardware mode is selected by connecting the H/S pin to ‘1’. In Hardware mode, 3 pins (DFC0, DFC1 &
S/AES) determine the Hardware mode number, according to
Table 5 . Start-up options are used exten-
sively in Hardware mode. Options include whether the serial audio output ports are master or slave, the
serial audio ports’ format and whether TCBL is an input or an output. Which output pins are used to set
which modes depends on which Hardware mode is being used.
13.1.2 Serial Audio Port Formats
In Hardware mode, only a limited number of alternative serial audio port formats are available. These for-
mats are described by Tables
6 and 7 , which define the equivalent Software mode bit settings for each
format. Timing diagrams are shown in Figures 17 and 18 .
For each Hardware mode, the following pages contain a data flow diagram, a pin-out drawing, a pin de-
scriptions list and a definition of the available start-up options.
DFC1 DFC0 S/AES Hardware Mode Number
0 0 0 1 - Default Data Flow, AES3 input
0 0 1 2 - Default Data Flow, serial input
0 1 - 3 - Transceive Flow, with SRC
1 0 - 4 - Transceive Flow, no SRC
1 1 0 5 - AES3 Rx only, AES3 input
1 1 1 6 - AES3 Tx only, serial input
Table 5. Hardware Mode Definitions
SOSF SORES1/0 SOJUST SODEL SOSPOL SOLRPOL
OF1 - Left-Justified 0 00 0 0 1 0
OF2 - I²S 24-bit data 0 00 0 1 0 1
OF3 - Right-Justified, Master
mode only 0 00 1 0 0 0
OF4 - I²S 16-bit data 0 10 0 1 0 1
OF5 - Direct AES3 data 0 11 0 0 1 0
Table 6. Serial Audio Output Formats Available in Hardware Mode
SISF SIRES1/0 SIJUST SIDEL SISPOL SILRPOL
IF1 - Left-Justified 0 00 0 0 1 0
IF2 - I²S 0 00 0 1 0 1
IF3 - Right-Justified 24-bit data 0 00 1 0 0 0
IF4 - Right-Justified 16-bit data 0 10 1 0 0 0
Table 7. Serial Audio Input Formats Available in Hardware Mode