SN8F2250B Series
USB 2.0 Full-Speed 8-Bit Micro-Controller
10.2 SIOM MODE REGISTER
0B4H
Bit 7
SENB
R/W
0
Bit 6
START
R/W
0
Bit 5
SRATE1
R/W
Bit 4
SRATE0
R/W
Bit 3
MLSB
R/W
0
Bit 2
SCKMD
R/W
Bit 1
CPOL
R/W
0
Bit 0
CPHA
R/W
0
SIOM
Read/Write
After reset
0
0
0
Bit 7
SENB: SIO function control bit.
0 = Disable (P5.0~P5.2 is general purpose I/O port).
1 = Enable (P5.0~P5.2 is SIO pins).
Bit 6
START: SIO progress control bit.
0 = End of transfer.
1 = Progressing.
Bit [5:4] SRATE1:0: SIO’s transfer rate select bit. These 2-bits are workless when SCKMD=1.
00 = Fcpu.
01 = Fcpu/32
10 = Fcpu/16
11 = Fcpu/8.
Bit 3
Bit 2
Bit 1
Bit 0
MLSB: MSB/LSB transfer first.
0 = MSB transmit first.
1 = LSB transmit first.
SCKMD: SIO’s clock mode select bit.
0 = Internal. (Master mode)
1 = External. (Slave mode)
CPOL: SIO’s transfer clock edge select bit.
0 = SCK idle status is low status
1 = SCK idle status is high status
CPHA: The Clock Phase bit controls the phase of the clock on which data is sampled.
0 = Data receive at the fisrt clock phase.
1 = Data receive at the second clock phase.
Note: 1. If SCKMD=1 for external clock, the SIO is in SLAVE mode. If SCKMD=0 for internal clock,
the SIO is in MASTER mode.
2. Don’t set SENB and START bits in the same time. That makes the SIO function error.
Because SIO function is shared with Port5 for P5.0 as SCK, P5.1 as SDI and P5.2 as SDO.
The following table shown the Port5[2:0] I/O mode behavior and setting when SIO function enable and disable.
SENB=1 (SIO Function Enable)
(SCKMD=1)
P5.0 will change to Input mode automatically, no matter what P5M
SIO source = External clock
(SCKMD=0)
setting
P5.0/SCK
P5.0 will change to Output mode automatically, no matter what
P5M setting
SIO source = Internal clock
P5.1/SDI
P5.1 must be set as Input mode in P5M ,or the SIO function will be abnormal
SIO = Transmitter/Receiver P5.2 will change to Output mode automatically, no matter what
P5M setting
P5.2/SDO
SENB=0 (SIO Function Disable)
P5.0/P5.1/P5.2 Port5[2:0] I/O mode are fully controlled by P5M when SIO function is disable
SONiX TECHNOLOGY CO., LTD
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Version 1.1
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