+++ /dev/null
-/* This implemenation is based on an example I once grabbed from
- the Philips bbs.
- Don't know who wrote it, but is has been hacked so heavely, he/she wouldn't
- recogize it anyway */
-
-#define DEBUG_I2C
-
-#ifdef DEBUG_I2C
-#include <stdio.h>
-#endif
-
-#include <ds80c390.h>
-#include "i2clole.h"
-
-#define I2CDELAY 1
-
-// we are (ab)using the CAN CTX and CRX for serial data and serial clock
-#define SCL_HIGH (P5 |= 1)
-#define SCL_LOW (P5 &= ~1)
-#define SDA_HIGH (P5 |= 2)
-#define SDA_LOW (P5 &= ~2)
-
-#define SDA_OUT(b) (b ? SDA_HIGH : SDA_LOW)
-#define SDA_IN ((P5>>1)&1)
-#define SCL_IN (P5&1)
-
-char i2cTransmitBuffer[I2C_BUFSIZE]; /* Global transfer buffers */
-char i2cReceiveBuffer[I2C_BUFSIZE];
-
-char i2cError = 0; /* Last error */
-
-
-/*
- * Makes sure that the bus is in a known condition. Returns 1 on success,
- * 0 if some other device is pulling on the bus.
- */
-
-char I2CReset(void)
-{
- //puts ("<I2CReset>");
- SDA_LOW;
- SCL_LOW;
- SCL_HIGH;
- SDA_HIGH;
- i2cError = 0;
- return (SCL_IN && SDA_IN);
-}
-
-
-/*
- * Generates a start condition on the bus. Returns 0 on success, 1 if some
- * other device is holding the bus.
- */
-
-char I2CStart(void)
-{
- //puts ("<I2CStart>");
-
- SDA_HIGH;
- SCL_HIGH;
- I2CDelay(I2CDELAY);
- SDA_LOW; /* Pull SDA down... */
- I2CDelay(I2CDELAY);
- SCL_LOW; /* ...and then SCL -> start condition. */
- I2CDelay(I2CDELAY);
- return 0;
-}
-
-
-/*
- * Generates a stop condition on the bus. Returns 0 on success, 1 if some
- * other device is holding the bus.
- */
-
-char I2CStop(void)
-{
- //puts ("<I2CStop>");
-
- SDA_LOW;
- SCL_HIGH; /* Let SCL go up */
- I2CDelay(I2CDELAY);
- SDA_HIGH; /* ...and then SDA up -> stop condition. */
- I2CDelay(I2CDELAY);
-
- return (SCL_IN && SDA_IN); /* Both will be up, if everything is fine */
-}
-
-
-/*
- * Clock out one bit.
- * Returns 0 on success, 1 if we lose arbitration.
- */
-
-char BitOutI2C(char bout)
-{
- //puts("<BitOutI2C>");
-
- SDA_OUT(bout); /* Put data out on SDA */
- I2CDelay(I2CDELAY);
- SCL_HIGH; /* Let SCL go up */
- while(!SCL_IN) /* Wait until all other devices are ready */
- {
- // should do a timeout here
- }
-
- if (SDA_IN != bout) /* Arbitration lost, release bus and return */
- {
- SDA_HIGH; /* Should be up anyway, but make sure */
- i2cError = I2CERR_LOST;
- I2CDumpError(i2cError);
- return 1;
- }
- I2CDelay(I2CDELAY);
- SCL_LOW; /* Pull SCL back down */
- I2CDelay(I2CDELAY);
- return 0; /* OK */
-}
-
-
-/*
- * Clock in one bit.
- */
-
-char BitInI2C(void)
-{
- char bin;
-
- //puts ("<BitInI2C>");
-
- // SDA is opencollector, so:
- SDA_HIGH;
-
- SCL_HIGH; /* Let SCL go up */
- while(!SCL_IN) /* Wait for other devices */
- {
- // should do a timeout here
- }
- bin = SDA_IN; /* Read in data */
- I2CDelay(I2CDELAY);
- SCL_LOW; /* Pull SCL back up */
- I2CDelay(I2CDELAY);
- return bin; /* Return the sampled bit */
-}
-
-
-/*
- * Send one byte on the bus. No start or stop conditions are generated here,
- * but i2cError will be set according to the result.
- * Returns 0 on success, 1 if we lose arbitration or if the slave doesn't
- * acknowledge the byte. Check i2cError for the actual result on error.
- */
-
-char ByteOutI2C(char dat)
-{
- char bit_count;
-
- //puts ("<ByteOutI2C>");
-
- bit_count = 8;
- while(bit_count) {
- if (dat & 0x80) {
- if (BitOutI2C(1)) {
- I2CDumpError(i2cError);
- return 1;
- }
- } else {
- if (BitOutI2C(0)) {
- I2CDumpError(i2cError);
- return 1;
- }
- }
- dat <<= 1;
- bit_count--;
- }
-
- if (BitInI2C()) {
- i2cError = I2CERR_NAK;
- I2CDumpError(i2cError);
- return 1;
- }
- return 0;
-}
-
-
-/*
- * Reads one byte in from the slave. Ack must be 1 if this is the last byte
- * to be read during this transfer, 0 otherwise (as per I2C bus specification,
- * the receiving master must acknowledge all but the last byte during a
- * transfer).
- */
-
-char I2CByteIn(char ack)
-{
- char bit_count, byte_in;
-
- //puts ("<I2CByteIn>");
-
- bit_count = 8;
- byte_in = 0;
-
- while(bit_count)
- {
- byte_in <<= 1;
- if (BitInI2C()) byte_in |= 0x01;
- bit_count--;
- }
-
- BitOutI2C(ack);
- SDA_HIGH; /* Added 18-Jul-95 - thanks to Ray Bellis */
- return byte_in;
-}
-
-
-/*
- * Send 'count' bytes to slave 'addr'.
- * Returns 0 on success. Stop condition is sent only when send_stop is true.
- */
-
-char I2CSendStop(char addr, char count, char send_stop)
-{
- char byteptr, byte_out;
-
- //puts ("<I2CSendStop>");
-
- if (I2CStart()) return 1;
- i2cError = 0;
-
- byte_out = addr & 0xfe; /* Ensure that it's a write address */
- count++; /* Include slave address to byte count */
- byteptr = 0;
- while(count)
- {
- if (ByteOutI2C(byte_out))
- {
- if (i2cError == I2CERR_NAK && send_stop) I2CStop();
- return i2cError;
- }
- byte_out = i2cTransmitBuffer[byteptr];
- byteptr++;
- count--;
- }
-
- if (send_stop) I2CStop();
- return 0;
-}
-
-
-/*
- * Read in 'count' bytes from slave 'addr'.
- * Returns 0 on success.
- */
-
-char i2c_recv(char addr, char count)
-{
- char byteptr, byte_in;
-
- //puts ("<i2c_rec>");
-
- if (I2CStart()) return 1;
- i2cError = 0;
- byteptr = 0;
-
- byte_in = addr | 0x01;
-
- if (ByteOutI2C(byte_in))
- {
- if (i2cError == I2CERR_NAK) I2CStop();
- return i2cError;
- }
-
- while(count)
- {
- count-=1;
- if (count) {
- byte_in = I2CByteIn(0);
- } else {
- byte_in = I2CByteIn(1); /* No ACK during last byte */
- }
- i2cReceiveBuffer[byteptr] = byte_in;
- byteptr++;
- }
-
- I2CStop();
-
- return (i2cError ? 1 : 0);
-}
-
-
-/*
- * Write 'tx_count' bytes to slave 'addr', then use a repeated start condition
- * to read 'rx_count' bytes from the same slave during the same transfer.
- * Returns 0 on success, 1 otherwise. On error, check i2cError for the actual
- * error value.
- */
-
-char I2CSendReceive(char addr, char tx_count, char rx_count)
-{
- //puts ("<i2c_send_recv>");
-
- if (I2CSendStop(addr, tx_count, 0))
- {
- /* If send fails, abort but don't send a stop condition if we lost
- arbitration */
-
- if (i2cError != I2CERR_LOST) I2CStop();
- return 1;
- }
-
- SDA_HIGH; /* One of these may be low now, in which case the next */
- SCL_HIGH; /* start condition wouldn't be detected so make */
- I2CDelay(I2CDELAY); /* sure that they're up and wait for one delay slot */
-
- if (i2c_recv((char)(addr|0x01), rx_count)) return 1;
- return (i2cError ? 1 : 0);
-}
-
-/*
- * Dump an error message.
- */
-
-void I2CDumpError(char error)
-{
-#ifdef DEBUG_I2C
- switch(error)
- {
- case 0:
- puts("I2C: OK.");
- break;
- case I2CERR_NAK:
- puts("I2C: Slave didn't acknowledge");
- break;
- case I2CERR_LOST:
- puts("I2C: Lost arbitration with another master");
- break;
- case I2CERR_TIMEOUT:
- puts("I2C: Timeout on bus");
- break;
- case I2CERR_BUS:
- puts("I2C: The bus is stuck");
- break;
- default:
- puts("I2C: Unknown error");
- break;
- }
-#endif
-}
-
-void I2CDelay(volatile long delay) {
- while (delay--)
- ;
-}
+++ /dev/null
-#ifndef _I2C_H
-#define _I2C_H
-
-#define I2C_BUFSIZE 128
-
-extern char I2CReset(void);
-extern char I2CStart(void);
-extern char I2CStop(void);
-extern char I2CSendStop(char addr, char count,
- char send_stop);
-extern char I2CReceive(char addr, char count);
-extern char I2CSendReceive(char addr, char tx_count, char rx_count);
-extern char I2CByteOut(char);
-extern void I2CDumpError(char);
-extern void I2CDelay(volatile long);
-
-/*
- * Macro for normal send transfer ending with a stop condition
- */
-
-#define I2CSend(addr, count) I2CSendStop(addr, count, 1)
-
-/*
- * Global variables in i2clole.c
- */
-
-extern char i2cTransmitBuffer[]; /* Transmit buffer */
-extern char i2cReceiveBuffer[]; /* Receive buffer */
-extern char i2cError; /* Set to last error value, see below */
-
-/*
- * I2C error values
- */
-
-#define I2CERR_OK 0 /* No error */
-#define I2CERR_NAK 1 /* No ACK from slave */
-#define I2CERR_LOST 2 /* Arbitration lost */
-#define I2CERR_BUS 3 /* Bus is stuck (not used yet) */
-#define I2CERR_TIMEOUT 4 /* Timeout on bus */
-
-#endif
-
-
-
-
-
-
-
projects / fw / sdcc / commitdiff