M16C/26 Using Key Input Interrupts
Contents
1. Input to respective peripheral functions Note 4 symbolizes a parasitic diode Do not apply a voltage higher than Vcc to each port Figure 1 Port 10 Block REU05B0052 0100Z June 2003 Page 1 of 7 M16C 26 E 2 NI ESAS Using Key Input Interrupts How the pins function is defined by setting special function registers in the M16C 26 We will focus on how to setup and use these pins to generate key input interrupts The two registers Port 10 Direction Register pd10 Ox3F5 and Key Input Interrupt Control Register kupic 0x04D needed to setup key input interrupts are shown in Figure 2 and Figure 3 A diagram of key input interrupt block is shown in Figure 4 Port Pi direction register PDi_1 PortPi direction register 0 Input mode Functions as an input port Port Pi2 direction register 4 Output mode T Port Pia direction register Functions as an output port perrea eesin Port Pi4 direction register mro ennsccannacannae Port Pis direction register Rebeca A ce nea PDi6 Port Pie direction register TTT TLE Port Pi7 direction register Figure 2 Port 10 Direction Register PD10 Sr be DS Me IS Me T 195 Symbol Address When reset PDi i 6 7 10 O3EE16 O3EF16 O3F6 16 0016 Bit symbol Bit name Function Ri i i Mpoo Por Pio direction register Interrupt control register Note 2 Symbol Address When reset BCNIC 004A 16 XXXXX0002 DMi2. ke ke e ke e ke Name Main main program loop Parameters None Returns None Description Handles processing and contains the infinite loop while waiting for key input interrupt FER A AR Ak AA A A A koc koe kk koc koc koe koe koe AA ke ko ke ko ke AA e AA ke ko ke ko e ko ke Sk e ko ke ko ke kc ke ko ke kc ke kc ke ke ke ke ke e ke e ke e x main To use key input interrupts the port direction where the key inputs are must be configured as inputs The M16C 26 has 4 key inputs which can be found on the upper 4 bits of port 10 P10 7 P10 6 P10 5 P10 4 We will set the direction for these 4 pins as inputs by setting it to 0 On the Mini 26 Board only P10 7 is used P10 7 is connected to pushbutton S2 The other 3 pins P10 6 P10 5 amp P10 4 are unused REU05B0052 0100Z June 2003 Page 5 of 7 M16C 26 E 2 NI ESAS Using Key Input Interrupts On the MSV30262 SKP Board P10 7 P10 6 amp P10 5 are connected to S4 S3 amp S2 respectively P10 4 is not used The lower 4 bits are don t cares and can be set to inputs or outputs depending on your hardware connection to these 4 pins In our example P10 0 amp P10 1 are set as inputs because on the Mini 26 and MSV30262 SKP Boards these are used as ADC inputs Ports P10 2 amp P10 3 are unused and we set these as outputs pd10 0x0C 00001100 Ports 10 7 10 6 10 5 10 4 as inputs where the key inputs
3. them Trouble with semiconductors may lead to personal injury fire or property damage Remember to give due consideration to safety when making your circuit designs with appropriate measures such as i placement of substitutive auxiliary circuits ii use of nonflammable material or iii prevention against any malfunction or mishap Notes regarding these materials These materials are intended as a reference to assist our customers in the selection of the Renesas Technology Corporation product best suited to the customer s application they do not convey any license under any intellectual property rights or any other rights belonging to Renesas Technology Corporation or a third party Renesas Technology Corporation assumes no responsibility for any damage or infringement of any third party s rights originating in the use of any product data diagrams charts programs algorithms or circuit application examples contained in these materials All information contained in these materials including product data diagrams charts programs and algorithms represents information on products at the time of publication of these materials and are subject to change by Renesas Technology Corporation without notice due to product improvements or other reasons It is therefore recommended that customers contact Renesas Technology Corporation or an authorized Renesas Technology Corporation product distributor for the latest product information before pu
4. 24 NE SAS APPLICATION NOTE M16C 26 Using Key Input Interrupts 1 0 Abstract The following article introduces and shows how to setup key input interrupt on the M16C 26 M30262 Flash microcontroller MCU A sample program was written for the MSV Mini26 SKP for evaluation purposes 2 0 Introduction The Renesas M16C 26 is a 16 bit MCU with multiple peripheral functions including handling interrupts generated by several sources One of the interrupt sources is the key input interrupt Key input interrupts can be used to wake up the M16C 26 from Wait or Stop Mode Key input interrupts can be used as alternative to monitor changes in the input pins i e use an interrupt instead of polling the input pins for changes It can be used as additional external interrupt pins for applications with interrupt sources more than the five external interrupt pins available on the M16C 26 3 0 Key Input Interrupt Pins The M16C 26 has four available key input pins that can be found on the upper four bits of Port 10 P10 7 P10 6 P10 5 amp P10 4 These four pins have other functions GPIO General Purpose Input Output and analog inputs to the internal AD converter A block diagram of Port 10 is shown in Figure 1 Pull up selection P100 to P103 Direction register SS inside dotted line not included P104 to P107 Data bus e Port latch TTI inside dotted line included Analog input
5. Kl Pull up Port P104 direction transistor register Piok O 1 o Figure 4 Key Input Interrupt Block 3 1 Key Input Interrupt Setup As described earlier M16C 26 registers are set to define how the upper four pins of Port 10 will function To setup the pins for key input interrupt function the following must be set e The pins used for the key input interrupt must be set as inputs in the Port 10 direction register PD 10 e The key input interrupt and global interrupt must be enabled If the key input interrupt or the global interrupt is disabled the pins become general purpose inputs To enable it an interrupt priority level from 1 to 7 must be given to key input interrupt control register kupic The FSET instruction must be executed to enable global interrupts Take note that interrupts are disabled by default after reset Refer to Interrupt Handler application note for details see Reference 3 2 Notes on Using the Key Input Interrupt Function Setting up and using key input interrupts can be implemented easily However we need to mention a few notes when using it The default state of key inputs is high at least 0 8Vcc according to M16C 26 datasheet A key input interrupt is generated on the falling edge high gt low transition of one of the inputs If one of the key inputs is always low a key input interrupt will not be generated As with any interrupt the vector address for the key input interrupt
6. are Ports 10 3 10 2 10 1 10 0 are B don t cares In our example we set these to outputs BI P10 0 don t care set to 0 input P10 1 don t care set to 0 input P10 2 don t care set to 1 output PIO0 3 don t care set to 1 output P10 4 key input 0 set to O input P10 5 key input 1 set to O input P10 6 key input 2 set to O input P10 7 key input 3 set to 0 input The next program step is not necessary as long as the pins are held at a high level when not generating a key input irq On the MSV30262 SKP the 3 inputs are held high with external pull up resistors and so the step can be omitted On the Mini 26 Board there is no external pull up for pushbutton S2 and so enable the internal pull up for the upper bits of port 10 Again this is only for the Mini 26 Board x pu25 1 enable internal pull up for upper 4 bits of P10 We need to enable the key input interrupt To accomplish this we set the key input interrupt control register to a non zero value ranging from 1 to 7 The value you set controls the software interrupt priority level 1 lowest and 7 highest Initialize LED ports so we can use it for this demo pd7 0x07 initialize LED s ports to outputs p7 0x07 turn off LED s asm FCLR I disable interrupts before changing irq registers kupic 2 enable key input irq by setting to non zero value 2
7. he complete project written in C can be compiled linked using KNC30 Compiler and will be provided upon request Please contact your Renesas representative for details RK KK RK AK AK A A AK A I A koe kc ke kk ck I ke Mini 26 Rev B Key Input Irq Program main c X v1 0 03 06 2003 i CKCkCk kc k kc k kc kckckckckckck kc kckckckckokckokckokckokckok kok ko ke ke ke ke e kx kx RK KK RK KK kk kk koe AR ke kk koe AA ke koc koe ko ke ko ke ko ke ko ke ko ke ko ke A ke AA ke ko ke koe kk kk kc ke kc ke ke ke kk e This Key Input Irq Program shows how to setup key input interrupts on the M16C 26 The program was written for the Mini 26 board The program is simple blink LEDs every time an interrupt occurs CkCkCk ck k kc k kc kckck kc k kc k kc kckck kk kc k kk kc k kk kk kck kc k kck kc k kck kc kckck kc kckckckckckckokckokckokckokckok ko ke ke ke ke e kx x Include the required header files include common sfr262 h M16C 26 special function register definitions Interrupt routines used for this demo must be defined with pragma INTERRUPT as shown below Vectors must also be set in sect30 keyinirq inc startup file to point to the interrupt routine pragma INTERRUPT ki irq Function prototypes void ki irq void General definitions define ON 0 define OFF 1 BRK KK RK AK AK A A A koc koe koe koe A ke A ke AA ke AA A AA A A ke AA ke ke AA ke A A ke ke ke ke
8. interrupt priority level 2 asm FSET I enable interrupts while 1 infinite loop p7 0x07 turn off LED s while waiting for key input irq REU05B0052 0100Z June 2003 Page 6 of 7 M16C 26 E 2 NI ESAS Using Key Input Interrupts 8 RK KK AK AK A AK A A koe koe AA A AA ke AA ke AA A AA e ko AA ke ko AA AA AA ke Sk AA e A ko ke AA ke A ke ke kkk Name ki irq Parameters None Returns None Description This is an key input interrupt routine processing when a key interrupt is generated A key input interrupt is generated when one of the 4 pins goes to a low level NOTE If one of the 4 inputs is always low a key input interrupt is NOT generated It is generated by the falling edge high gt low of one of the key inputs For this demo on the Mini 26 Board the key input interrupt is generated when pushbutton S2 is pressed The routine turns Red and Green LEDs FER A AK ek A A A A kk koe koc koe koc koe AA ke AA ke A ke koe ko ke A ke koe ko ke ko ke Sk ke ko ke A ke ke ke ko ke ke ke ke ke ke ke e ke e ke e x void ki irq void p7 0x02 turn on Red and Green LEDs while pl0 7 20 wait here until pushbutton is released REU05B0052 0100Z June 2003 Page 7 of 7 Keep safety first in your circuit designs Renesas Technology Corporation puts the maximum effort into making semiconductor products better and more reliable but there is always the possibility that trouble may occur with
9. lC i 0 1 004B16 004C 16 XXXXX0002 KUPIC 004D 16 XXXXX0002 ADIC 004E 16 XXXXX0002 SiTIC i 0 to 2 005116 005316 004F e XXXXX0002 SiRIC i 0 to 2 005216 005416 005016 XXXXX0002 TAIIC i 0 to 4 005516 to 005916 XXXXX0002 LEAK oe r TBIGHEO to 2 005A 6 to 005C e XXXXX0002 Bit symbol Bit name Function ILVLO Interrupt priority level select bit Level 0 interrupt disabled Level 1 Level 2 Level 3 Level 4 Level 5 Md a Level 6 Level 7 p 7 Nothing is assigned In an attempt to write to these bits write O The value if read turns out to be indeterminate Note 1 This bit can only be accessed for reset 7 0 but cannot be accessed for set 7 1 Note 2 To rewrite the interrupt control register do so at a point that does not generate the interrupt request for that register For details see the precautions for interrupts Figure 3 Key Input Interrupt Control Register kupic REU05B0052 0100Z June 2003 Page 2 of 7 M16C 26 E 2 NI ESAS Using Key Input Interrupts Port P104 P107 pull up select bit Pull up Key input interrupt control register address 004D16 transistor Port P107 direction register Port P107 direction register P107 Kla O Pull up Port P106 direction transistor register Key input interrupt request Interrupt control circuit P10e Kl2 Port P105 direction Pull up register transistor P105
10. must also be set so the MCU knows the routine to process when the interrupt occurs The interrupt vector is set in the sect30 inc startup file during firmware development Refer to Interrupt Handler application note for details see Reference REU05B0052 0100Z June 2003 Page 3 of 7 M16C 26 E 2 NI ESAS Using Key Input Interrupts 4 0 Key Input Interrupt Sample Program A sample program was written for the MSV Mini26 SKP Board as an example The Red and Green LED s are turned on every time a key input interrupt is generated i e when pushbutton S2 is pressed Releasing the pushbutton switch turns off the LED s To get a copy of the sample program contact your Renesas representative 5 0 Conclusion Key input interrupts can be used in a lot of applications Setting up and using the function can be easily implemented on the M16C 26 6 0 Reference Renesas Technology Corporation Semiconductor Home Page http www renesas com E mail Support support apl 2renesas com Data Sheets e M16C 26 datasheets M30262eds pdf User s Manual e M16C 20 60 C Language Programming Manual 6020c pdf e M16C 20 60 Software Manual 6020software pdf e Interrupt Handler App Note M16C26 Interrupt Handlers in C doc e MSV30262 SKP Users Manual Users Manual Mini26B pdf REU05B0052 0100Z June 2003 Page 4 of 7 M16C 26 E 2 NI ESAS Using Key Input Interrupts 7 0 Software Code The key input interrupt sample program is shown below T
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