R01UH0823EJ0100 Rev.1.00
Page 1317 of 1823
Jul 31, 2019
RX23W Group
37. Serial Sound Interface (SSI)
(6) Master Transceiver
This mode allows serial data transmission and reception between this module and another device. The clock and word
select signals are internally derived from the master clock. The format of these signals is defined in the configuration
fields of this module.
(7) Operating Settings Related to Word Length
All bits related to the SSICR register's word length are valid in non-compressed modes. There are many configurations
this module supports, but some of the combinations are shown below for the I
2
S compatible format, MSB-first and left-
justified format, and MSB-first and right-justified format.
In this section SSITXD0 and SSIRXD0 are referred to SSIDATA.
I
2
S Compatible Format
show the I
2
S compatible format both without and with padding.
Padding occurs when the data word length is smaller than the system word length.
Figure 37.2
I
2
S Compatible Format (without Padding)
Figure 37.3
I
2
S Compatible Format (with Padding)
Prev. sample
Next sample
SSICR.SCKP bit = 0, SSICR.SWSP bit = 0, SSICR.DEL bit = 0, SSICR.CHNL[1:0] bits = 00b
System word length = data word length
SSISCK
SSIWS
SSIDATA
System word 1 =
data word 1
System word 2 =
data word 2
MSB
LSB+1
LSB MSB
LSB+1
LSB
Next
SSICR.SCKP bit = 0, SSICR.SWSP bit = 0, SSICR.DEL bit = 0, SSICR.CHNL[1:0] bits = 00b, SSICR.SPDP bit = 0,
SSICR.SDTA bit = 0
System word length > data word length
SSISCK
SSIWS
SSIDATA
System word 1
MSB
LSB
MSB
LSB
Data word 1
System word 2
Padding
Data word 2
Padding