s3c72m9 Samsung Semiconductor, Inc., s3c72m9 Datasheet - Page 333

• Manufacturer Part Number: s3c72m9
• Description: The S3c72m5/s3c72m7/s3c72m9 Single-chip Cmos Microcontroller Has Been Designed For High Performance Using Samsung S
• Manufacturer: Samsung Semiconductor, Inc.

S3C72M5/C72M7/C72M9/P72M9 (Preliminary Spec)
SERIAL I/O BUFFER REGISTER (SBUF)
The serial I/O buffer register ,SBUF, can be read or written using 8-bit RAM control instructions. Following a RESET,
the value of SBUF is undetermined.
When the serial interface operates in transmit-and-receive mode (SMOD.1 = "1"), transmit data in the SIO buffer
register are output to the SO pin (P0.1) at the rate of one bit for each falling edge of the SIO clock. Receive data are
simultaneously input from the SI pin (P0.2) to SBUF at the rate of one bit for each rising edge of the SIO clock.
When receive-only mode is used, incoming data are input to the SIO buffer at the rate of one bit for each rising edge
of the SIO clock.
F
1. Transmit the data value 48H through the serial I/O interface using an internal clock frequency of fxx/2
2. Use CPU clock to transfer and receive serial data at high speed:
STEST
MSB-first mode:
PROGRAMMING TIP — Setting Transmit/Receive Modes for Serial I/O
BITS
SMB
LD
LD
LD
LD
LD
LD
BITR
LD
LD
LD
LD
LD
LD
BITR
BTSTZ
JR
LD
LD
[S3C72M5/C72M7/C72M9]
SCK/P0.0
SO/P0.1
EMB
15
EA,#03H
PMG1,EA
EA,#48H
SBUF,EA
EA,#0EEH
SMOD,EA
EMB
EA,#03H
PMG1,EA
EA,TDATA
SBUF,EA
EA,#4FH
SMOD,EA
IES
IRQS
STEST
EA,SBUF
RDATA,EA
; P0.0/SCK and P0.1/SO
; TDATA address = Bank0 (20H–7FH)
; SIO start
; SIO interrupt disable
; RDATA address = Bank0 (20H–7FH)
; P0.0/SCK and P0.1 / SO
; SIO data transfer
External
Device
Output, P0.2/SI
Output
SERIAL I/O INTERFACE
4
Input
and in
13-5