SN8F2250B Series
USB 2.0 Full-Speed 8-Bit Micro-Controller
10 SERIAL INPUT/OUTPUT TRANSCEIVER
10.1 OVERVIEW
The SIO (serial input/output) transceiver allows high-speed synchronous data transfer between the SN8F2250B series
MCU and peripheral devices or between several SN8F2250B devices. These peripheral devices may be Serial
EEPROMs, shift registers, display drivers, etc. The SN8F2250B SIO features include the following:
z
z
z
z
z
z
z
Full-duplex, 3-wire synchronous data transfer
TX/RX or TX Only mode
Master (SCK is clock output) or Slave (SCK is clock input) operation
MSB/LSB first data transfer
SDO (P5.2) is programmable open-drain output pin for multiple salve devices application
Two programmable bit rates (Only in master mode)
End-of-Transfer interrupt
The SIOM register can control SIO operating function, such as: transmit/receive, clock rate, transfer edge and starting
this circuit. This SIO circuit will transmit or receive 8-bit data automatically by setting SENB and START bits in SIOM
register. The SIOB is an 8-bit buffer, which is designed to store transfer data. SIOC and SIOR are designed to
generate SIO’s clock source with auto-reload function. The 3-bit I/O counter can monitor the operation of SIO and
announce an interrupt request after transmitting/receiving 8-bit data. After transferring 8-bit data, this circuit will be
disabled automatically and re-transfer data by programming SIOM register.
SENB
MLSB
SI
8-bit Receive Buffer
CPUM1,0
SENB
MLSB
SO
SIOB 8-bit Buffer
CPHA
CPUM1,0
SENB
SCLKMD
CPOL
SCK
SIO Time Out
SIO 3-bit I/O Counter
CPUM1,0
SENB
START
÷1
÷8
Fcpu
SIO 8-bit Counter
÷16
÷32
Auto-Reload
SIOR Register
CPUM1,0
Srate1,0
SIO Interface Circuit Diagram
SONiX TECHNOLOGY CO., LTD
Page 110
Version 1.1
SONIX [ SONIX TECHNOLOGY COMPANY ]
