SN8P275X Series
8-bit micro-controller build-in 12-bit ADC
SONiX TECHNOLOGY CO., LTD
Page 118
Version 0.7
9.5 SIOR REGISTER DESCRIPTION
SIOR initial value = 0000 0000
0B5H
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
SIOR
SIOR7 SIOR6 SIOR5 SIOR4 SIOR3 SIOR2 SIOR1 SIOR0
Read/Write
W W W W W W W W
After
reset
0 0 0 0 0 0 0 0
The SIOR is designed for the SIO counter to reload the counted value when end of counting. It is like a post-scaler of
SIO clock source and let SIO has more flexible to setting SCK range. Users can set the SIOR value to setup SIO
transfer time. To setup SIOR value equation to desire transfer time is as following.
SCK frequency = SIO rate / (256 - SIOR)
SIOR = 256 - ( 1 / ( SCK frequency ) * SIO rate )
Example: Setup the SIO clock to be 5KHz. Fosc = 3.58MHz. SIO’s rate = Fcpu = Fosc/4.
SIOR = 256 – (1/(5KHz) * 3.58MHz/4)
= 256 – (0.0002*895000)
= 256 – 179
= 77