To all our customers
Regarding the change of names mentioned in the document, such as Mitsubishi
Electric and Mitsubishi XX, to Renesas Technology Corp.
The semiconductor operations of Hitachi and Mitsubishi Electric were transferred to Renesas
Technology Corporation on April 1st 2003. These operations include microcomputer, logic, analog
and discrete devices, and memory chips other than DRAMs (flash memory, SRAMs etc.)
Accordingly, although Mitsubishi Electric, Mitsubishi Electric Corporation, Mitsubishi
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Except for our corporate trademark, logo and corporate statement, no changes whatsoever have been
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contents of the document itself.
Note : Mitsubishi Electric will continue the business operations of high frequency & optical devices
and power devices.
Renesas Technology Corp.
Customer Support Dept.
April 1, 2003
APPLICATION NOTE
M16C/62
Event Counter Mode on the M16C/62
1. Abstract
Event counters are useful in automated packaging lines, tachometers, and mechanical equipment
monitoring. Also, the event counters on the M16C/62 can be configured to interrupt on a single event,
adding to the interrupt input pins. The following article describes how to configure the M16C/62 timers as
event counters, referred to as “Event Counter Mode”.
2. Introduction
The Mitsubishi M16C/62 is a 16-bit MCU, based on the M16C CPU core, with an impressive list of
features including 10-bit A/D, D/A, UARTS, Timers, DMA, etc., and up to 256k bytes of user flash. The
MCU has 5 ‘A’ timers and 6 ‘B’ timers. All 11 timers can operate in “Event Counter Mode”.
Timer A has the following additional modes of operation:
•
•
•
Timer Mode
PWM Mode
One-Shot Mode
Timer B has the following additional modes of operation:
•
•
Timer Mode
Pulse Period/Pulse Width Measurement Mode
Figure 1 illustrates the operation of timer A, and Figure 2, timer B. Note that there are some differences
between the two timers but both operate similarly in Event Counter Mode. The remainder of this article
focuses on setting up timer A0 in Event Counter Mode.
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M16C/62
Event Counter Mode on the M16C/62
Figure 1. Block Diagram of Timer A
Figure 2. Block Diagram of Timer B
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M16C/62
Event Counter Mode on the M16C/62
3. Event Counter Mode Description
In general, the Timer TAi or TBi register counts an input signal and, at any time, the count value can be
read. When the timer overflows (for up-count) or underflows (down-count) the timer interrupt request bit is
set and an interrupt is generated if the timer interrupt priority level is set above the current CPU priority
level (if the I flag in the CPU flag registers is cleared, the interrupt will not be serviced until the flag is set).
If at any time during counting the count start flag is cleared, counting is suspended until set. This is
illustrated in Figure 3.
Figure 3. Operation Timing of Event Counter Mode, Reload Type Selected
Besides having the option of counting up or down, Event Counter Mode has many other options such as
count source (TAiIN or TBiIN input pin or another timer), reload or free running type, etc. and these
options vary depending on which timer is used. The options and the timers they are associated with are
summarized in Table 1, Table 2, and Table 3.
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M16C/62
Event Counter Mode on the M16C/62
Table 1. Timer A Specifications in Event Counter Mode (Single Phase Mode Only)
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M16C/62
Event Counter Mode on the M16C/62
Table 2. Timer Specifications in Event Counter Mode (when processing two-phase pulse signal with
timers A2, A3, and A4)
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M16C/62
Event Counter Mode on the M16C/62
Table 3. Timer B Specifications in Event Counter Mode
4. Configuring Event Counter Mode
To configure a timer for Event Counter Mode:
1.
Load the timer mode register, TAiMR.
Select Event Counter Mode: bits TMOD0 = 1, TMOD1 = 0.
Set the remaining bits (MR0, MR1, MR2, TCK0, TCK1) depending on required functions (see mode
register diagrams below).
2.
Load the TAi or TBi register with the count source.
3.
Select the trigger via the TRGSR or ONSF register (N/A for Timer B).
4.
Select up or down count via the UDF register (N/A for Timer B, Timer B counts down only).
5.
Set the timer ‘interrupt priority level’, TAiIC or TBiIC, to at least 1 if required.
6.
Enable interrupts (CPU I flag set).
7.
Set the ‘start count’ flag bit, TAiS or TBiS, in the ‘count start flag’ register, TABSR or TBSR.
It is not necessary to perform these steps in the order listed, but the mode register should be loaded
before the ‘start count’ flag is set. Also, the priority level should not be modified when there is a possibility
of an interrupt occurring.
The required registers are shown in Figure 4 to Figure 7, Figure 9, Figure 10 and Figure 12.
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M16C/62
Event Counter Mode on the M16C/62
Figure 4. Timer Ai Mode Register in Event Counter Mode
Figure 5. Timer Ai Mode Register (When Not Using Two-Phase Pulse Signal Processing)
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M16C/62
Event Counter Mode on the M16C/62
Figure 6. Timer Ai Mode Register (When Using Two-Phase Pulse Signal Processing)
Figure 7. Timer Bi Register
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M16C/62
Event Counter Mode on the M16C/62
Figure 8. One-Shot Start Flag
Figure 9. Trigger Select Register
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M16C/62
Event Counter Mode on the M16C/62
Figure 10. Timer Ai Register
Figure 11. Count Start Flag
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M16C/62
Event Counter Mode on the M16C/62
Figure 12. Interrupt Control Register
Figure 13. Timer B3, 4, 5 Count Start Flag
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M16C/62
Event Counter Mode on the M16C/62
5. References
•
•
•
•
•
NC30 Ver. 4.0 User’s Manual, NC30UE.pdf
M16C/60 and M16C/20 C Language Programming Manual, 6020EC.pdf
M16C/62 datasheets, 62aeds.pdf
M16C/62 User’s Manual, 62eum.pdf
Application Note: Writing Interrupt Handlers in C for the M16C
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M16C/62
Event Counter Mode on the M16C/62
6. Software Code
The software supplied by Mitsubishi Electric & Electronics USA, Inc. is intended and supplied for use on Mitsubishi
Electric products. This software is owned by Mitsubishi Electric & Electronics USA, Inc. or Mitsubishi Electric
Corporation and is protected under applicable copyright laws. All rights are reserved.
THIS SOFTWARE IS PROVIDED “AS IS”. NO WARRANTIES, WHETHER EXPRESS, IMPLIED, OR STATUTORY,
INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE APPLY TO THIS SOFTWARE. MITSUBISHI ELECTRIC & ELECTRONICS USA, INC.
AND MITSUBISHI ELECTRIC CORPORATION RESERVE THE RIGHT, WITHOUT NOTICE, TO MAKE CHANGES
TO THIS SOFTWARE. NEITHER MITSUBISHI ELECTRIC & ELECTRONICS USA, INC. NOR MITSUBISHI
ELECTRIC CORPORATION SHALL, IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL, OR
CONSEQUENTIAL DAMAGES FOR ANY REASON WHATSOEVER ARISING OUT OF THE USE OR
APPLICATION OF THIS SOFTWARE.
Below is a program written for Mitsubishi’s NC30 compiler to illustrate how to configuring Event Counter
Mode. The program counts 100 falling edges on the P7.1 (TA0IN) pin then flashes D6 on the
MDECE0620 Starter Kit Board.
To get familiar with this mode, try changing to up-count, the count value or even switch to a different
timer (e.g. TA1, TB0, etc).
/*****************************************************************************
*
*
File Name: event_mode.c
*
*
Content: Example program using Timer A in "Event Counter Mode". This program
*
is written for the Event Counter Mode application note. This program
*
works with the MDECE0620 starter kit board.
*
Compiled with NC30 ver. 3.20.00.
*
All timing based on 16 Mhz Xtal
*
*
Copyright,2001 MITSUBISHI ELECTRIC CORPORATION
*
AND MITSUBISHI SEMICONDUCTOR SYSTEM CORPORATION
*
and Mitsubishi Electric and Electronics USA
*=============================================================================
*
$Log:$
*===========================================================================*/
#include "sfr62.h"
#define TIME_CONFIG 0x01 /* 00000001 value to load into timer mode register
||||||||_ TMOD0,TMOD1: EVENT COUNTER MODE
||||||____ MR0:
NO PULSE OUTPUT
|||||_____ MR1:
COUNT FALLING EDGES
||||_______MR2:
USE UP/DOWN FLAG
|||_______ MR3:
= 0 IN EVENT COUNTER MODE
||________ TCK0:
RELOAD TYPE
|__________TCK1:
BIT NOT USED
*/
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M16C/62
Event Counter Mode on the M16C/62
#define
#define
#define
#define
CNTR_IPL 0x03
LED p7_7
LED_PORT_DIRECTION
OUTPUT 1
pd7_7
// TA0 priority interrupt level
//p6_0 LED port on MSV1632 board
//pd6_0 LED port direction on MSV1632 board
//prototypes
void init(void);
#pragma INTERRUPT /B TimerA0Int
void TimerA0Int(void);
/*****************************************************************************
Name:
TimerA0Int()
Parameters: none
Returns: nothing
Description:Timer A0 Interrupt Service Routine. Interrupts every 100 falling
edges on the TA0in pin. Flashes the LED and increments 'count'.
**************************************************************************** */
void TimerA0Int(void)
{
int delaycntr;
delaycntr = 0;
count++;
// e.g for an automated packaging line, counts # of cases
LED = 1;
while( delaycntr <0xffff) //software delay for flashing LED
delaycntr++;
LED = 0;
}
/*****************************************************************************
Name:
main()
Parameters: none
Returns: nothing
Description: initializes variables and LED port. Then does nothing but
wait for TA0 interrupts.
**************************************************************************** */
void main (void)
{ int temp;
count = 0;
LED_PORT_DIRECTION = OUTPUT;
init();
while (1);
}
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M16C/62
Event Counter Mode on the M16C/62
/*****************************************************************************
Name: initial()
Parameters: none
Returns: nothing
Description: Timer TA0 setup for 5msec interrupts.
**************************************************************************** */
void init()
{
ta0 = 100;
//e.g for an automated packaging line, 100 items per cases
/* the following procedure for writing an Interrupt Priority Level follows that as
described in the M16C
data sheets under 'Interrupts' */
_asm ("
fclr i") ;
ta0ic |= CNTR_IPL;
ta0mr = TIME_CONFIG;
_asm ("
fset i");
ta0s = 1;
//turn off interrupts before modifying IPL
// use read-modify-write instruction to write IPL
//start counting
}
In order for this program to run properly, timer A0’s interrupt vector needs to
point to the function. The interrupt vector table is near the end of the startup
file “sect30.inc”. Insert the function label “_TimerA0Int” into the interrupt
vector table at vector 21 as shown below.
;*******************************************************************************
;
;
C Compiler for M16C/62
;
;
Copyright,2000 MITSUBISHI ELECTRIC CORPORATION
;
AND MITSUBISHI SEMICONDUCTOR SYSTEM CORPORATION
;
and Mitsubishi Electric and Electronics USA
;
All Rights Reserved.
;
;
Written by T.Aoyama
;
Modified for use on MSV1632 Starter Kit.
;
sect30.inc
: section definition
;
This program is applicable when using KD30 and the ROM Monitor.
;******************************************************************************
;--------------------------------------------------------------:
:
:
:
:
AN-DECE-MCU-5-A
February 2002
15
M16C/62
Event Counter Mode on the M16C/62
.lword
.lword
.lword
.lword
.lword
.lword
.lword
.glb
.lword
.lword
.lword
.lword
.lword
.lword
.lword
.lword
.lword
.lword
.lword
AN-DECE-MCU-5-A
dummy_int
dummy_int
dummy_int
dummy_int
dummy_int
0fcb6bh
0fcb6bh
_ TimerA0Int
_TimerA0Int
dummy_int
dummy_int
dummy_int
dummy_int
dummy_int
dummy_int
dummy_int
dummy_int
dummy_int
dummy_int
:
:
:
:
:
;
;
;
;
;
;
;
A-D(for user)(vector 14)
uart2 transmit(for user)(vector 15)
uart2 receive(for user)(vector 16)
uart0 transmit(for user)(vector 17)
uart0 receive(for user)(vector 18)
uart1 transmit(for user)(vector 19)
uart1 receive(for user)(vector 20)
;
;
;
;
;
;
;
;
;
;
;
timer A0(for user)(vector 21)
timer A1(for user)(vector 22)
timer A2(for user)(vector 23)
timer A3(for user)(vector 24)
timer A4(for user)(vector 25)
timer B0(for user)(vector 26)
timer B1(for user)(vector 27)
timer B2(for user)(vector 28)
int0 (for user)(vector 29)
int1 (for user)(vector 30)
int2 (for user)(vector 31)
February 2002
16
Keep safety first in your circuit designs!
•
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circuits, (ii) use of non-flammable material, or (iii) prevention against any malfunction or mishap.
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AN-DECE-MCU-5-A
February 2002
18