
233
CHAPTER 14 16-BIT RELOAD TIMER (WITH EVENT COUNT FUNCTION)
14.4
Underflow Operation of 16-bit Reload Timer
An underflow is defined for this timer as the time when the counter value changes from
"0000
H
"
to "FFFF
H
". Therefore, an underflow occurs after (reload register s 1)
counts.
■
Underflow Operation of 16-bit Reload Timer
If the RELD bit in the control register is "1" when the underflow occurs, the contents of the reload register
is loaded into the counter and counting continues. When RELD is "0", counting stops with the counter at
"FFFF
H
".
The UF bit in the control register is set when the underflow occurs. If the INTE bit is "1" at this time, an
interrupt request is generated.
Figure 14.4-1 shows the underflow operation of 16-bit reload timer.
Figure 14.4-1 Underflow Operation of 16-bit Reload Timer
0000
H
-1
-1
-1
[RELD=1]
Count clock
Counter
Data load
Underflo
w
set
0000
H
FFFF
H
[RELD=0]
Count clock
Counter
Reload data
Underflo
w
set
Summary of Contents for MB90390 Series
Page 2: ......
Page 4: ......
Page 17: ...xiii APPENDIX D List of Interrupt Vectors 690 INDEX 695 ...
Page 18: ...xiv ...
Page 132: ...104 CHAPTER 5 CLOCKS ...
Page 152: ...124 CHAPTER 6 CLOCK MODULATOR ...
Page 210: ...182 CHAPTER 11 TIME BASE TIMER ...
Page 218: ...190 CHAPTER 12 WATCHDOG TIMER ...
Page 264: ...236 CHAPTER 14 16 BIT RELOAD TIMER WITH EVENT COUNT FUNCTION ...
Page 274: ...246 CHAPTER 15 WATCH TIMER ...
Page 306: ...278 CHAPTER 17 DTP EXTERNAL INTERRUPTS ...
Page 338: ...310 CHAPTER 18 8 10 BIT A D CONVERTER ...
Page 364: ...336 CHAPTER 19 UART0 UART1 ...
Page 398: ...370 CHAPTER 20 UART2 UART3 Figure 20 5 2 ORE Set Timing Receive data RDRF ORE ...
Page 432: ...404 CHAPTER 20 UART2 UART3 ...
Page 482: ...454 CHAPTER 22 SERIAL I O ...
Page 560: ...532 CHAPTER 24 STEPPING MOTOR CONTROLLER ...
Page 582: ...554 CHAPTER 27 ROM MIRRORING MODULE ...
Page 632: ...604 CHAPTER 29 EXAMPLES OF SERIAL PROGRAMMING CONNECTION ...
Page 722: ...694 APPENDIX ...
Page 723: ...695 INDEX The index follows on the next page This is listed in alphabetic order ...
Page 740: ......