AN205281 F²MC-8FX Family MB95200H/210H Series External Interrupts.pdf

AN205281
F²MC-8FX Family, MB95200H/210H Series External Interrupts
This application note describes how to set and use the External Interrupt and also describes the function of the
External Interrupts and gives some examples.
Contents
1
2
Introduction ...............................................................1
External Interrupt ......................................................1
2.1
Key Features ...................................................1
2.2
Block Diagram .................................................2
2.3
Connection Diagram ........................................2
2.4
Registers..........................................................3
3
External Interrupt Timing ..........................................4
4
External Interrupt Examples .....................................5
1
4.1
4.2
Basic Functions ............................................... 5
External interrupts and Wake Up from Stop
Mode ................................................................ 7
5
Precautions when Using External Interrupt Circuit ... 9
6
Additional Information ............................................... 9
6.1
Sample Code ................................................. 10
7
Document History ................................................... 15
Introduction
This application note describes how to set and use the External Interrupt.
This application note describes the function of the External Interrupts and gives some examples.
2
External Interrupt
This chapter describes the basic features of the interrupt module
2.1
Key Features


Edge detection circuit
External Interrupt control register
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2.2
Block Diagram
Figure 1 shows the internal block diagram of an External Interrupt channel.
Figure 1. External Interrupts Block Diagram
2.3
Connection Diagram
Figure 2 shows the connection diagram depicting how the External Interrupt pin INTn is interfaced to the external
circuitry.
The pull-up resistor R is connected to limit the current when the key is pressed. The capacitor (hardware debounce)
circuit shown in dotted line is optional, and is used to eliminate the bouncing of the switch. The RC time constant
needs to be chosen according to the bouncing time or debounce delay of the switch. If such arrangement is not used,
then the bouncing needs to be taken care in the software and vice versa.
The INTn needs to be configured to detect a falling edge.
Figure 2. External Interrupt Connection Diagram (Application of switch function)
Please note that this application is only used for switch or keyboard functions.
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2.4
Registers
Please refer to MB95200H/210H Series Hardware Manual Chapter 15 for detailed register setting.
2.4.1
E x t e r n a l I n t e r r u p t C o n t r o l R e g i s t e r ( E I C x y)
The external interrupt control register is used to control interrupt and select the edge polarity for the external interrupt
input and control interrupts.
Table 1. External Interrupt Control Register
2.4.2
bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Corresponding Ext.
Int. No.
EIC10
EIR1
SL11
SL10
EIE1
EIR0
SL01
SL00
EIE0
INT03
INT02
EIC20
EIR1
SL11
SL10
EIE1
EIR0
SL01
SL00
EIE0
INT05
INT04
EIC30
EIR1
SL11
SL10
EIE1
EIR0
SL01
SL00
EIE0
INT07
INT06
I n t e r r u p t L e ve l S e t t i n g R e g i s t e r s ( I L R 0 t o I L R 5 )
Table 2. Configuration of External Interrupt Level Setting Registers
ILR0
L03
[1:0]
L02
[1:0]
L01
[1:0]
L00
[1:0]
ILR1
L07
[1:0]
L06
[1:0]
L05
[1:0]
L04
[1:0]
ILR2
L11
[1:0]
L10
[1:0]
L09
[1:0]
L08
[1:0]
ILR3
L15
[1:0]
L14
[1:0]
L13
[1:0]
L012
[1:0]
ILR4
L19
[1:0]
L18
[1:0]
L17
[1:0]
L016
[1:0]
ILR5
L23
[1:0]
L22
[1:0]
L21
[1:0]
L020
[1:0]
One of the interrupt level setting registers (ILR0) contains 4 pairs of bits assigned to interrupt requests from an
External Interrupt.
Table 3. Interrupt Source
Interrupt Request No.
Bit Name in Interrupt Level Setting
Register
Interrupt Source
IRQ0
L00[1:0]
External Interrupt ch.4
IRQ1
L01[1:0]
External Interrupt ch.5
IRQ2
L02[1:0]
External Interrupt ch.2/ ch.6
IRQ3
L03[1:0]
External Interrupt ch.3/ ch.7
Each pair of bits (interrupt level setting bits as two-bit data) sets an interrupt level.
Table 4. Relationships between Interrupt Level Setting Bits and Interrupts Levels
LXX[1:0]
Interrupt Level
00
0
01
1
10
2
11
3
Priority
Highest
Lowest (No interrupts accepted)
XX: represents the corresponding interrupt number 00 to 03
During execution of a main program, the interrupt level bits in the condition code register (CCR: IL1, IL0) usually
indicates “11B”.
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3
External Interrupt Timing
This chapter describes timing of external interrupts
The following figure shows events for External Interrupts timing.
After receiving an interrupt, the CPU requires 9 machine clock cycles to perform the following interrupt processing
setup:



Save the program counter (PC) and program status (PS) value
Set the PC to the start address (interrupt vector) of interrupt service routine
Update the interrupt level bits (PS:CCR:IL1,IL0) in the program status (PS) register
Figure 3. Interrupt Processing Time
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4
External Interrupt Examples
This chapter describes examples on external interrupts
4.1
Basic Functions
The following example shows how to set up the External Interrupt Channel 2 and Channel 6 for operation.
Program will enter ISR while generate an Ext Int on channel 2 or channel 6, and clear flag and wait next external
interrupt signal.
/* initial interrupt setting */
void InitExtInt0206 (void)
{
AIDRL |= 0x04;
// disable AN02 input
DDR0 &= 0xBB;
// P02 P06 input
EIC10 = 0x03;
EIC30 = 0x03;
//
//
//
//
External
& Enable
External
& Enable
Interrupt 2 rising
external interrupt
Interrupt 6 rising
external interrupt
edge
output
edge
output
}
/* external ISR */
__interrupt void ExInt0206 (void)
{
if (EIC10_EIR0)
// Ext Int 02 ?
{
EIC10_EIR0 = 0;
// Clear interrupt request flag
...
// interrupt server routine
}
if (EIC30_EIR0)
{
EIC30_EIR0 = 0;
...
// Ext Int 06 ?
// Clear interrupt request flag
// interrupt server routine
}
}
/* main routine */
void main (void)
{
...
InitExtInt0206();
...
}
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F²MC-8FX Family, MB95200H/210H Series External Interrupts
Please note that the corresponding interrupt vector and level should be defined in the vector.c module of Cypress’s
standard template project.
...
ILR0 = 0xCF;
//IRQ2: external interrupt ch2 | ch6
...
__interrupt void ExInt0206 (void);
// Prototype
...
#pragma intvect ExInt0206
2
// IRQ2: external interrupt ch2 | ch6
Refer to Appendix Sample Code for project “EI_Basic”.
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F²MC-8FX Family, MB95200H/210H Series External Interrupts
4.2
External interrupts and Wake Up from Stop Mode
The following example shows that External Interrupts can be used to request stop mode and wake up the MCU from
this mode.
External Interrupt 2 is used to wake up the MCU while External Interrupt 6 is used to request stop mode.
At the beginning, program will run in normal mode, after an external interrupt (channel 6), set flag from “RUNMODE”
to “STOPREQUEST” in the ISR, then MCU will enter stop mode, and also the external interrupt 2 will wake up the
MCU. Therefore, the MCU mode can switch via external interrupt 2 and 6.
// initialise external interrupt
void InitExtInt0206 (void)
{
AIDRL |= 0x04;
//
DDR0 &= 0xBB;
//
EIC10 = 0x03;
//
//
EIC30 = 0x03;
//
//
}
2 & 6
disable AN02 input
P02 P06 input
External Interrupt 2 rising
& Enable external interrupt
External Interrupt 6 rising
& Enable external interrupt
/* external ISR */
__interrupt void ExInt0206 (void)
{
if (EIC10_EIR0)
{
status = RUNMODE;
EIC10_EIE0 = 0;
EIC10_EIR0 = 0;
EIC10_EIE0 = 1;
}
if (EIC30_EIR0)
{
status = STOPREQUEST;
EIC30_EIE0 = 0;
EIC30_EIR0 = 0;
EIC30_EIE0 = 1;
}
}
edge
output
edge
output
// Ext Int 02 ?
// disable external interrupt 2
// clear interrupt request flag
// enable interrupt request
// Ext Int 06 ?
// disable external interrupt 6
// clear interrupt request flag
// enable interrupt request
/* main routine */
void main (void)
{
...
InitExtInt0206();
...
▼
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F²MC-8FX Family, MB95200H/210H Series External Interrupts
▲
status = RUNMODE;
while (1)
{
if (status == STOPREQUEST) // stop mode request
{
PDR0_P00 = 1;
STBC_STP = 1;
}
else
{
// enter stop mode
// run mode
for (i = 0; i < 50000; i ++)
//wait loop
{
__asm(“\tNOP”);
__asm(“\tNOP”);
}
PDR0_P00 = ~PDR0_P00;
// show that MCU is running
}
}
}
Please note that the corresponding interrupt vector and level should be defined in the vector.c module of Cypress’s
standard template project.
/* Interrupt level setting */
void InitIrqLevels (void)
{
...
ILR0 = 0xDF;
...
// IRQ2: external interrupt ch2 | cha6
}
__interrupt void ExInt0206 (void);
// Prototype
...
#pragma intvect ExInt0206
2
// IRQ2: external interrupt ch2 | ch6
...
Refer to Appendix Sample Code for project “EI_ModeSwitch”.
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5
Precautions when Using External Interrupt Circuit
Precautions
6

Set the interrupt request enable bit (EIE) to “0” (disabling interrupt requests) in the process of setting the edge
polarity select bit (SL). Moreover, clear the external interrupt request flag bit (EIR) to “0” after the setting of the
edge polarity.

The operation cannot recover from the interrupt processing routine if the external interrupt request flag bit is “1”
and the interrupt request enable bit is enabled. Always clear the external interrupt request flag bit in the interrupt
processing routine.
Additional Information
For more Information on MB95200 Products, visit the following website:
http://www.cypress.com/8fx-mb95200
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F²MC-8FX Family, MB95200H/210H Series External Interrupts
6.1
Sample Code
6.1.1
Project Name: EI_Basic
Basic external ISR
main.c
#include "mb95200.h"
/*--------------------------------------------------------------------------name: InitExtInt0206 ();
function: initial external interrupt
-----------------------------------------------------------------------------*/
void InitExtInt0206 (void)
{
AIDRL |= 0x04;
// disable AN02 input
DDR0 &= 0xBB;
// P02 P06 input
EIC10 = 0x03;
// External Interrupt 2 rising edge
// & Enable interrupt output
EIC30 = 0x03;
// External Interrupt 6 rising edge
// & Enable external interrupt output
}
/*--------------------------------------------------------------------------name: ExInt0206 ();
function: enter while generate an Ext Int
-----------------------------------------------------------------------------*/
__interrupt void ExInt0206 (void)
{
if (EIC10_EIR0)
{
EIC10_EIR0 = 0;
// Clear interrupt request flag
// interrupt server routine
}
if (EIC30_EIR0)
{
EIC30_EIR0 = 0;
// Clear interrupt request flag
// interrupt server routine
}
}
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F²MC-8FX Family, MB95200H/210H Series External Interrupts
/*--------------------------------------------------------------------------name: main ();
function: main loop
-----------------------------------------------------------------------------*/
void main(void)
{
InitExtInt0206();
InitIrqLevels();
__EI();
while(1);
}
vector.c
#include "mb95200.h"
/*--------------------------------------------------------------------------name: InitIrqLevels ();
function: Interrupt level (priority) setting
-----------------------------------------------------------------------------*/
void InitIrqLevels(void)
{
ILR0 = 0xCF;
// IRQ0:
external interrupt ch4
// IRQ1:
external interrupt ch5
// IRQ2:
external interrupt ch2 | ch6
// IRQ3:
external interrupt ch3 | ch7
}
/*--------------------------------------------------------------------------Prototypes
-----------------------------------------------------------------------------*/
__interrupt void ExInt0206 (void);
/*--------------------------------------------------------------------------Vector definition
-----------------------------------------------------------------------------*/
#pragma intvect ExInt0206
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2
// IRQ2:
external interrupt ch2 | ch6
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F²MC-8FX Family, MB95200H/210H Series External Interrupts
6.1.2
Project Name: EI_ModeSwitch
The MCU wakes up from stop mode via an external interrupt
main.c
#include "mb95200.h"
#define RUNMODE
1
#define STOPREQUEST
0
unsigned char status;
/*--------------------------------------------------------------------------name: InitExtInt0206 ();
function: initial external interrupt
-----------------------------------------------------------------------------*/
void InitExtInt0206 (void)
{
AIDRL |= 0x04;
// disable AN02 input
DDR0 &= 0xBB;
// P02 P06 input
EIC10 = 0x03;
// External Interrupt 2 rising edge
// & Enable interrupt output
EIC30 = 0x03;
// External Interrupt 6 rising edge
// & Enable external interrupt output
}
/*--------------------------------------------------------------------------name: ExInt0206 ();
function: mode switch
-----------------------------------------------------------------------------*/
__interrupt void ExInt0206 (void)
{
if (EIC10_EIR0)
{
status = RUNMODE;
EIC10_EIE0 = 0;
// disable external interrupt 2
EIC10_EIR0 = 0;
// clear interrupt request flag
EIC10_EIE0 = 1;
// enable interrupt request
}
if (EIC30_EIR0)
{
status = STOPREQUEST;
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EIC30_EIE0 = 0;
// disable external interrupt 6
EIC30_EIR0 = 0;
// clear interrupt request flag
EIC30_EIE0 = 1;
// enable interrupt request
}
}
/*--------------------------------------------------------------------------name: main ();
function: main loop
-----------------------------------------------------------------------------*/
void main (void)
{
unsigned int i;
InitExtInt0206();
DDR0_P05 = 1;
InitIrqLevels();
__EI();
status = RUNMODE;
while (1)
{
if (status == STOPREQUEST) // stop mode request
{
PDR0_P00 = 1;
STBC_STP = 1;
// go to stop mode
}
else
// run mode
{
for (i = 0; i < 5000; i ++)
//wait loop
{
__asm("\tNOP");
__asm("\tNOP");
}
PDR0_P05 = ~PDR0_P05;
// show, that MCU is running
}
}
}
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F²MC-8FX Family, MB95200H/210H Series External Interrupts
vector.c
#include "mb95200.h"
/*--------------------------------------------------------------------------name: InitIrqLevels ();
function: Interrupt level (priority) setting
-----------------------------------------------------------------------------*/
void InitIrqLevels(void)
{
ILR0 = 0xCF;
// IRQ0:
external interrupt ch4
// IRQ1:
external interrupt ch5
// IRQ2:
external interrupt ch2 | ch6
// IRQ3:
external interrupt ch3 | ch7
}
/*--------------------------------------------------------------------------Prototypes
-----------------------------------------------------------------------------*/
__interrupt void ExInt0206 (void);
/*--------------------------------------------------------------------------Vector definition
-----------------------------------------------------------------------------*/
#pragma intvect ExInt0206
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2
// IRQ2:
external interrupt ch2 | ch6
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F²MC-8FX Family, MB95200H/210H Series External Interrupts
7
Document History
Document Title: AN205281 - F²MC-8FX Family, MB95200H/210H Series External Interrupts
Document Number: 002-05281
Revision
**
ECN
-
Orig. of
Change
HUAL
Submission
Date
Description of Change
03/20/2008
Initial release
07/18/2008
Added URL in chapter 6 Additional Information; modified
Some sample code.
*A
www.cypress.com
5264352
HUAL
06/03/2016
Migrated Spansion Application Note MCU-AN-500007-E-11 to Cypress
format
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F²MC-8FX Family, MB95200H/210H Series External Interrupts
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