IBM H8 user manual A/D + Pwm

HTEB1

User manual

3.4 A/D + PWM

This sample shows the usage of the A/D converter. We sample the voltage of P1/P2, filter it and show the result on the LCD. On D/A-Con you will see a reversed voltage at P2 – built with a RC-filter from TOW (P76).

/*------------------------------------------------------------------

**AD_PWM Demo shows some funcions of the A/D converter

**and the use of PWM (= inverse output from P2) at D/A-Con

**-----------------------------------------------------------------			*/
#include "mydefs.h"			// with further includes!
#include "stdlib.h"			// for abs()
void wait(u16 wastetime)		// local LCD port delay
{
while(wastetime--	);
}
/*
LCD-Port / Bits on TinyEvalBoard
RS = P75, R/W	= P74,	EN	= P20, DATA = P5
*/

//some defines for easy access #define CLEAR_LCD_RS (PDR7 &= ~0x20)

#define SET_LCD_RS		(PDR7 = 0x20)
#define CLEAR_LCD_RW	(PDR7 &= ~0x10)
#define SET_LCD_RW		(PDR7 = 0x10)
#define CLEAR_LCD_EN	(PDR2 &= ~0x01)
#define SET_LCD_EN		(PDR2 = 0x01)
#define LCD_DATA_PORT (PDR5)
#define LCD_DATA_CTRL (PCR5)
#define LCD_OUT	0xff
#define LCD_IN 0x00
#define LCD_WAIT		{wait(100);}
void LCDWriteCmd(u8 cmd)		// write cmd to LCD port
{
CLEAR_LCD_RS;
CLEAR_LCD_RW;
SET_LCD_EN;
LCD_DATA_PORT = cmd;
LCD_WAIT;
CLEAR_LCD_EN;
LCD_WAIT;
}
void LCDWriteData(u8 data)		// write data to LCD port
{
SET_LCD_RS;
CLEAR_LCD_RW;
SET_LCD_EN;
LCD_DATA_PORT = data;
LCD_WAIT;
CLEAR_LCD_EN;
LCD_WAIT;
}
u8 LCDReadStatus(void)		// get the LCD status register
{
u8 status;
CLEAR_LCD_RS;
SET_LCD_RW;

Issue 0.2 Page 41 07/2002