NEC PD754144 - Manual (Page 212)

CHAPTER 7 INTERRUPT AND TEST FUNCTIONS
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User’s Manual U10676EJ3V0UM
7.10 Test Function
7.10.1 Types of test sources
The
µPD754244 has a test source, INT2. INT2 is an edge-detection testable input.
Table 7-5. Types of Test Sources
Test Source Internal/External
INT2 (detects falling edge of input to KR4 to KR7 pins) External
7.10.2 Hardware controlling test function
(1) Test request and test enable flags
The test request flag (IRQ2) is set to “1” when a test request is generated (INT2). Clear this flag to “0” by
software after the test processing has been executed.
A test enable flag (IE2) is provided for the test request flag. When this flag is “1”, the standby release signal
is enabled; when it is “0”, the signal is disabled.
If both the test request flag and test enable flag are set to “1”, the standby release signal is generated.
Table 7-6 shows the signals that set the test request flags.
Table 7-6. Test Request Flag Setting Signals
Test Request Flag Test Request Flag Setting Signal Test Enable Flag
IRQ2 Detection of falling edge of any input to KR4/P70-KR7/P73 pins. IE2
Edge to be detected is selected by INT2 edge detection mode
register (IM2)
(2) Hardware of key interrupts (KR4 to KR7)
Figure 7-10 shows the configuration of KR4 to KR7.
The IRQ2 setting signal is output when a specified edge is detected on either of the key interrupts. Which
pin’s falling input is selected is specified by using the INT2 edge detection mode register (IM2).
Figure 7-11 shows the format of IM2. IM2 is set by a 4-bit manipulation instruction. When the reset signal
is asserted, all the bits of this register are cleared to “0”.