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120 lines
2.0 KiB
120 lines
2.0 KiB
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#include "i2c.h" |
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#define I2CBASE 0xE001C000 |
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#define I2CONSET 0x00 |
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#define I2STAT 0x04 |
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#define I2DAT 0x08 |
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#define I2ADR 0x0c |
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#define I2SCLH 0x10 |
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#define I2SCLL 0x14 |
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#define I2CONCLR 0x18 |
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#define IREG(x) (((volatile unsigned char *)I2CBASE)[x]) |
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#define IWREG(x) (((volatile unsigned int *)I2CBASE)[(x)/sizeof(unsigned int)]) |
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#define AAFLAG (1<<2) |
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#define SIFLAG (1<<3) |
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#define STOFLAG (1<<4) |
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#define STAFLAG (1<<5) |
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#define SI (IREG(I2CONSET) & SIFLAG) |
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void init_i2c(void) |
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{ |
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IREG(I2CONSET) = 0x40; /* Enable I2C ready for Master Tx */ |
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/* Set up for just under 400kHz */ |
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#if 0 |
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IWREG(I2SCLL) = (25 * 100); |
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IWREG(I2SCLH) = (12 * 100); |
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#else |
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# if 0 |
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IWREG(I2SCLL) = 1475; /* ~5kHz */ |
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IWREG(I2SCLH) = 1475; |
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# else |
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IWREG(I2SCLL) = 73; /* ~100kHz */ |
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IWREG(I2SCLH) = 73; |
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# endif |
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#endif |
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} |
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int i2cstat; |
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int i2c_wait(void) |
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{ |
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int stat; |
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while (!SI); |
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stat = IREG(I2STAT); |
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i2cstat = stat; |
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return stat; |
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} |
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int i2c_conreg(void) |
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{ |
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return IREG(I2CONSET); |
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} |
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int i2c_statreg(void) |
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{ |
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return IREG(I2STAT); |
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} |
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bool i2c_send_start(void) |
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{ |
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IREG(I2CONCLR) = STOFLAG | STAFLAG; |
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IREG(I2CONSET) = STAFLAG; |
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switch (i2c_wait()) { |
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case 0x08: |
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case 0x10: |
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return TRUE; |
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default: |
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i2c_send_stop(); |
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return FALSE; |
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} |
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} |
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bool i2c_send_address(int addr, bool write) |
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{ |
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return i2c_send_data((addr<<1) + (write?0:1)); |
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} |
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bool i2c_send_data(unsigned int data) |
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{ |
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IREG(I2DAT) = data; |
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IREG(I2CONCLR) = STAFLAG | STOFLAG | SIFLAG; |
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switch (i2c_wait()) { |
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case 0x18: |
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case 0x28: |
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case 0x40: |
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return TRUE; |
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default: |
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i2c_send_stop(); |
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return FALSE; |
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} |
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} |
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bool i2c_receive_data(unsigned int *data, bool last) |
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{ |
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if (!last) |
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IREG(I2CONSET) = AAFLAG; |
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IREG(I2CONCLR) = STAFLAG | STOFLAG | SIFLAG | (last?AAFLAG:0); |
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switch (i2c_wait()) { |
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case 0x50: |
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case 0x58: |
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*data = IREG(I2DAT); |
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return TRUE; |
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default: |
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i2c_send_stop(); |
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return FALSE; |
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} |
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} |
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void i2c_send_stop(void) |
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{ |
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IREG(I2CONCLR) = STAFLAG | AAFLAG; |
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IREG(I2CONSET) = STOFLAG; |
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IREG(I2CONCLR) = SIFLAG; |
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/* Don't think we need to wait here. Could be wrong. */ |
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} |
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