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CHAPTER 18 DTP/EXTERNAL INTERRUPT CIRCUIT
18.6
Usage Notes on the DTP/External Interrupt Circuit
Notes on the signal to be input to the DTP/external interrupt circuit, release from
standby mode, and interrupts are given below.
■
Usage Notes on the DTP/external Interrupt Circuit
●
Conditions for external peripherals using the DTP function
To support the DTP function, external peripherals must be able to clear data transfer requests automatically
in response to transfer operations. If a transfer request is not removed within three machine cycles of the
start of transfer, the DTP/external interrupt circuit interprets the request as another transfer request.
●
Input polarities of external interrupts
•
If the request level setting register (ELVR) is set so that an edge is detected, the pulse width must be at
least three machine cycles for the edge to be detected.
•
If the request input level is level setting, the pulse width requires a longer period than the minimum
pulse width stated on the data sheet. Also, as long as the interrupt input pin retains the active level,
interrupt requests continue to be generated to the interrupt controller, even if the DTP/external interrupt
cause register is cleared.
•
If the register is set for level detection, and the level to be detected as an interrupt cause is input, cause
F/F in the DTP/interrupt cause register (EIRR) is set to "1" to store the cause, as shown in Figure 18.6-1.
Even if the cause is removed, the request to the interrupt controller remains active provided the output
of interrupt requests is enabled. Thus, to cancel the request to the interrupt controller, clear the external
interrupt request flag bit and cause F/F, as shown in Figure 18.6-2.
Figure 18.6-1 Clearing the Cause Retention Circuit when a Level is Specified
DTP/external
Cause flip-flop
Enable gate
To interrupt
The cause is stored until the register is cleared
(in the EIRR register)
controller
interrupt cause
(interrupt
request)
DTP/interrupt input
detection circuit
Содержание MB90460 Series
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Страница 41: ...22 CHAPTER 1 OVERVIEW ...
Страница 45: ...26 CHAPTER 2 NOTES ON HANDLING DEVICES ...
Страница 83: ...64 CHAPTER 3 CPU ...
Страница 95: ...76 CHAPTER 4 RESET ...
Страница 107: ...88 CHAPTER 5 CLOCK ...
Страница 131: ...112 CHAPTER 6 LOW POWER CONSUMPTION MODE ...
Страница 175: ...156 CHAPTER 7 INTERRUPT ...
Страница 181: ...162 CHAPTER 8 MODE SETTING ...
Страница 223: ...204 CHAPTER 9 I O PORT ...
Страница 237: ...218 CHAPTER 10 TIME BASE TIMER ...
Страница 247: ...228 CHAPTER 11 WATCHDOG TIMER ...
Страница 275: ...256 CHAPTER 12 16 BIT RELOAD TIMER ...
Страница 373: ...354 CHAPTER 14 MULTI FUNCTIONAL TIMER ...
Страница 485: ...466 CHAPTER 16 PWC Timer ...
Страница 531: ...512 CHAPTER 17 UART ...
Страница 559: ...540 CHAPTER 19 DELAYED INTERRUPT GENERATOR MODULE ...
Страница 589: ...570 CHAPTER 20 8 10 BIT A D CONVERTER ...
Страница 601: ...582 CHAPTER 21 ROM CORRECTION FUNCTION ...
Страница 633: ...614 CHAPTER 23 512K 1024K BIT FLASH MEMORY ...
Страница 645: ...626 CHAPTER 24 EXAMPLE OF F2 MC 16LX MB90F462 F462A F463A CONNECTION FOR SERIAL WRITING ...
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Страница 716: ...697 INDEX INDEX The index follows on the next page This is listed in alphabetic order ...
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