Samsung KS57C2308 manual Smod Serial I/O Mode Register, FE1H, FE0H

KS57C2308/P2308/C2316/P2316MEMORY MAP

SMOD — Serial I/O Mode Register FE1H, FE0H

Bit

Identifier

RESET Value

Read/Write

Bit Addressing

7	6	5	4	3	2	1	0
.7	.6	.5	"0"	.3	.2	.1	.0
0	0	0	0	0	0	0	0
W	W	W	W	R/W	W	W	W
8	8	8	8	1/8	8	8	8

.7–.5	Serial I/O Clock Selection and SBUF R/W Status Control Bits
	0	0	0	Use an external clock at the SCK pin;
				Enable SBUF when SIO operation is halted or when SCK goes high
	0	0	1	Use the TOL0 clock from timer/counter 0;
				Enable SBUF when SIO operation is halted or when SCK goes high
	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/210)
	1	1	1	262 kHz clock (fxx/24); Note: You cannot select a fxx/24 clock
				frequency if you have selected a CPU clock of fxx/64
	NOTE: All kHz frequency ratings assume a system clock of 4.19MHz

.4	Bit 4
	0	Always logic zero
.3	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

.2 Enable/Disable SIO Data Shifter and Clock Counter Bit

0Disable the data shifter and clock counter; the contents of IRQS flag is retained when serial transmission is completed

1Enable the data shifter and clock counter; The IRQS flag is set to logic one when serial transmission is completed

.1 Serial I/O Transmission Mode Selection Bit

0Receive-only mode; output buffer is off

1Transmit-and-receive mode; output buffer is on

.0 LSB/MSB Transmission Mode Selection Bit

0Transmit the most significant bit (MSB) first

1Transmit the least significant bit (LSB) first

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