336
CHAPTER 14 8-BIT SERIAL I/O
14.11
Program Example for 8-Bit Serial I/O
This section provides program example for 8-bit serial I/O.
■
Program Example for 8-bit Serial Output
●
Processing Specifications
•
The 8-bit serial output program outputs 8-bit serial data (55
H
) from the SO pin of the 8-bit serial I/O.
When serial I/O transfer terminates, an interrupt occurs.
•
The program resets transfer data with the interrupt processing routine and outputs it continuously.
•
The program operates in accordance with the internal shift clock. This clock is output from the SCK
pin.
•
If the shift clock is 32t
INST
when the maximum gear speed (1 instruction cycle = 4/F
CH
) at the 12.5-
MHz oscillation (F
CH
), the transfer rate and interrupt cycle are as follows:
Transfer rate = 12.5 MHz/4/32 = 97.7 kbps, interrupt cycle = 8
×
32
×
4/10 MHz = 81.92
µ
s
●
Coding example
SMR
EQU
0039H
; Address of serial mode register
SDR
EQU
003AH
; Address of serial data register
SSEL
EQU
003BH
; Address of serial/UART selection register
SIOF
EQU
SMR:7
; Defines the interrupt request flag bit.
SST
EQU
SMR:0
; Defines the serial I/O transfer start bit.
ILR4
EQU
007EH
; Address of interrupt request setting register 4
INT_V
DSEG
ABS
; [DATA SEGMENT]
ORG
0FFE2H
IRQC
DW
WARI
; Sets an interrupt vector.
INT_V
ENDS
;--------------------Main program--------------------------------------------------------------------------
CSEG
; [CODE SEGMENT]
; The stack pointer (SP), etc., are already initialized.
:
CLRI
; Disables interrupts.
CLRB
SST
; Stops serial I/O transfer.
MOV
ILR4,#11111101B
; Sets the interrupt level to 1.
MOV
SDR,#55H
; Sets transfer data (55H).
MOV
SMR,#01111000B
; Clears the interrupt request flag, allows the interrupt
request output, shift clock output (SCK), and serial data
output (SO), selects 32tINST, and sets LSB first.
MOV
SSEL,#00000001B
; Selects the 8-bit serial I/O.
SETB
SST
; Starts serial I/O transfer.
SETI
; Enables interrupts.
:
Summary of Contents for F2MC-8L F202RA
Page 2: ......
Page 4: ......
Page 32: ...16 CHAPTER 1 OVERVIEW ...
Page 90: ...74 CHAPTER 3 CPU ...
Page 142: ...126 CHAPTER 5 TIME BASE TIMER POPW A RETI ENDS END ...
Page 150: ...134 CHAPTER 6 WATCHDOG TIMER ...
Page 176: ...160 CHAPTER 7 8 BIT PWM TIMER ...
Page 220: ...204 CHAPTER 8 8 16 BIT CAPTURE TIMER COUNTER ...
Page 240: ...224 CHAPTER 9 12 BIT PPG TIMER ...
Page 274: ...258 CHAPTER 11 EXTERNAL INTERRUPT CIRCUIT 2 LEVEL ...
Page 362: ...346 CHAPTER 15 BUZZER OUTPUT ...
Page 390: ...374 CHAPTER 17 FLASH MEMORY ...
Page 419: ...403 INDEX INDEX The index follows on the next page This is listed in alphabetic order ...
Page 434: ...418 INDEX ...
Page 436: ......