Samsung KS57C2308 Manual page 69

KS57C2308/P2308/C2316/P2316
SMOD
— Serial I/O Mode Register
Bit
Identifier
Value
RESET
Read/Write
Bit Addressing
.7–.5
.4
.3
.2
.1
.0
7 6
.7 .6
0 0
W W
8 8
Serial I/O Clock Selection and SBUF R/W Status Control Bits
0 0 0 Use an external clock at the
Enable SBUF when SIO operation is halted or when
0 0 1 Use the TOL0 clock from timer/counter 0;
Enable SBUF when SIO operation is halted or when
0 1 x Use the selected CPU clock (fxx/4, 8, or 64; "fxx" is the system
clock); Enable SBUF read/write operation. "x" means "don't care."
1 0 0
4.09 kHz clock (fxx/2
1 1 1
262 kHz clock (fxx/2
frequency if you have selected a CPU clock of fxx/64
NOTE: All kHz frequency ratings assume a system clock of 4.19MHz
Bit 4
0 Always logic zero
Initiate Serial I/O Operation Bit
1 Clear IRQS flag and 3-bit clock counter to logic zero; then initiate serial
transmission. When SIO transmission starts, this bit is cleared by hardware to
logic zero
Enable/Disable SIO Data Shifter and Clock Counter Bit
0 Disable the data shifter and clock counter; the contents of IRQS flag is
retained when serial transmission is completed
1 Enable the data shifter and clock counter; The IRQS flag is set to logic one
when serial transmission is completed
Serial I/O Transmission Mode Selection Bit
0 Receive-only mode; output buffer is off
1 Transmit-and-receive mode; output buffer is on
LSB/MSB Transmission Mode Selection Bit
0 Transmit the most significant bit (MSB) first
1 Transmit the least significant bit (LSB) first
5 4 3
.5 "0" .3
0 0 0
W W R/W
8 8 1/8
SCK
10
)
4
); Note: You cannot select a fxx/2
FE1H, FE0H
2 1
.2 .1
0 0
W W
8 8
pin;
SCK
SCK
4
MEMORY MAP
0
.0
0
W
8
goes high
goes high
clock
4-27