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synced 2025-11-15 08:02:34 -05:00
revert the last changes because they prevent some Gigabeats from shutting down
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@13372 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Marcoen Hirschberg
parent
d92e09556f
commit
685001f0d4
1 changed files with 107 additions and 86 deletions
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@ -1,5 +1,6 @@
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#include "config.h"
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#include "cpu.h"
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#include <stdbool.h>
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#include "kernel.h"
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#include "system.h"
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#include "logf.h"
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@ -8,132 +9,147 @@
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#define SLAVE_ADDRESS 0xCC
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#define USE_ASM
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/* This I2C driver tristates the outputs instead of driving logic high's */
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#define SDA_LO (GPHDAT &= ~(1 << 9))
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#define SDA_HI (GPHDAT |= (1 << 9))
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#define SDA_INPUT (GPHCON &= ~(3 << 18))
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#define SDA_OUTPUT (GPHCON |= (1 << 18))
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#define SDA (GPHDAT & (1 << 9))
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#define SDA_LO_OUT (GPHCON |= (1 << 18));(GPHDAT &= ~(1 << 9));
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#define SDA_HI_IN (GPHCON &= ~(3 << 18))
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#define SCL_LO (GPHDAT &= ~(1 << 10))
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#define SCL_HI (GPHDAT |= (1 << 10))
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#define SCL_INPUT (GPHCON &= ~(3 << 20))
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#define SCL_OUTPUT (GPHCON |= (1 << 20))
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#define SCL (GPHDAT & (1 << 10))
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#define SCL_LO_OUT (GPHCON |= (1 << 20));(GPHDAT &= ~(1 << 10));
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#define SCL_HI_IN (GPHCON &= ~(3 << 20));while(!SCL);
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/* The SC606 can clock at 400KHz:
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* Clock period high is 600nS and low is 1300nS
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* The high and low times are different enough to need different timings
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* cycles delayed = 2 + 4 * loops
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* 100MHz = 10nS per cycle: LO:1300nS=130:33 HI:600nS=60:15
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* 300MHz = 3.33nS per cycle:
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* LO:1300nS=394:99
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* HI:600nS=182:21
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* MID(50/50):950(1900/2)ns=288:72
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*/
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#define SCL_SDA_HI (GPHDAT |= (3 << 9))
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#ifdef USE_ASM
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/* The SC606 can clock at 400KHz: */
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/* Clock period high is 600nS and low is 1300nS */
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/* The high and low times are different enough to need different timings */
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/* cycles delayed = 30 + 7 * loops */
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/* 100MHz = 10nS per cycle: LO:1300nS=130:14 HI:600nS=60:9 */
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/* 300MHz = 3.36nS per cycle: LO:1300nS=387:51 HI:600nS=179:21 */
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#define DELAY_LO do{int x;for(x=51;x;x--);} while (0)
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#define DELAY do{int x;for(x=35;x;x--);} while (0)
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#define DELAY_HI do{int x;for(x=21;x;x--);} while (0)
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#define DELAY_LO 99
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#define DELAY_MID 72
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#define DELAY_HI 46
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/* This delay loop takes 4 cycles/loop to execute plus 2 for setup */
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#define DELAY(dly) \
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asm volatile( "mov r0,%0 \n" \
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"1: \n" \
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"subs r0,r0,#1 \n" \
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"bhi 1b \n" \
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: : "r"((dly)) : "r0" );
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#else
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#define DELAY_LO 51
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#define DELAY_MID 35
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#define DELAY_HI 21
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#define DELAY(dly) do{int x;for(x=(dly);x;x--);} while (0)
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#endif
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static void sc606_i2c_start(void)
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{
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SDA_HI_IN;
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SCL_HI_IN;
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DELAY(DELAY_MID);
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SDA_LO_OUT;
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DELAY(DELAY_MID);
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SCL_LO_OUT;
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SCL_SDA_HI;
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DELAY;
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SDA_LO;
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DELAY;
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SCL_LO;
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}
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static void sc606_i2c_restart(void)
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{
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SCL_SDA_HI;
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DELAY;
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SDA_LO;
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DELAY;
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SCL_LO;
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}
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static void sc606_i2c_stop(void)
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{
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SDA_LO_OUT;
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SCL_HI_IN;
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DELAY(DELAY_HI);
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SDA_HI_IN;
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SDA_LO;
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SCL_HI;
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DELAY_HI;
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SDA_HI;
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}
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static void sc606_i2c_ack(void)
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{
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SDA_HI_IN;
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SCL_HI_IN;
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DELAY(DELAY_HI);
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SCL_LO_OUT;
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SDA_LO;
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SCL_HI;
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DELAY_HI;
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SCL_LO;
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}
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static bool sc606_i2c_getack(void)
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static int sc606_i2c_getack(void)
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{
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bool ret;
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int ret;
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SDA_HI_IN;
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DELAY(DELAY_MID);
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SCL_HI_IN;
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/* Don't need a delay since follows a data bit with a delay on the end */
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SDA_INPUT; /* And set to input */
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DELAY;
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SCL_HI;
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ret = !SDA;
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ret = (SDA != 0); /* ack failed if SDA is not low */
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DELAY_HI;
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SCL_LO_OUT;
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DELAY(DELAY_LO);
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SCL_LO;
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DELAY_LO;
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SDA_HI;
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SDA_OUTPUT;
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DELAY_LO;
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return ret;
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}
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static void sc606_i2c_outb(unsigned char byte)
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{
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int i;
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/* clock out each bit, MSB first */
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for ( i=0x80; i; i>>=1 )
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for (i = 0x80; i; i >>= 1)
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{
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if ( i & byte )
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SDA_HI_IN;
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if (i & byte)
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{
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SDA_HI;
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}
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else
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SDA_LO_OUT;
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DELAY(DELAY_MID);
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SCL_HI_IN;
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DELAY(DELAY_HI);
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SCL_LO_OUT;
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{
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SDA_LO;
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}
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DELAY;
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SCL_HI;
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DELAY_HI;
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SCL_LO;
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DELAY_LO;
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}
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SDA_HI;
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}
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static unsigned char sc606_i2c_inb(void)
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{
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int i;
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unsigned char byte = 0;
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int i;
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unsigned char byte = 0;
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/* clock in each bit, MSB first */
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SDA_HI_IN;
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for ( i=0x80; i; i>>=1 )
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{
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SCL_HI_IN;
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DELAY(DELAY_HI);
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if ( SDA )
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byte |= i;
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SCL_LO_OUT;
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DELAY(DELAY_LO);
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}
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SDA_INPUT; /* And set to input */
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/* clock in each bit, MSB first */
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for (i = 0x80; i; i >>= 1) {
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SCL_HI;
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sc606_i2c_ack();
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return byte;
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if (SDA)
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byte |= i;
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SCL_LO;
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}
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SDA_OUTPUT;
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sc606_i2c_ack();
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return byte;
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}
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/* returns number of acks that were bad */
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int sc606_write(unsigned char reg, unsigned char data)
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{
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@ -147,7 +163,7 @@ int sc606_write(unsigned char reg, unsigned char data)
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sc606_i2c_outb(reg);
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x += sc606_i2c_getack();
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sc606_i2c_start();
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sc606_i2c_restart();
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sc606_i2c_outb(SLAVE_ADDRESS);
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x += sc606_i2c_getack();
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@ -160,6 +176,8 @@ int sc606_write(unsigned char reg, unsigned char data)
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return x;
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}
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int sc606_read(unsigned char reg, unsigned char* data)
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{
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int x;
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@ -171,7 +189,7 @@ int sc606_read(unsigned char reg, unsigned char* data)
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sc606_i2c_outb(reg);
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x += sc606_i2c_getack();
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sc606_i2c_start();
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sc606_i2c_restart();
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sc606_i2c_outb(SLAVE_ADDRESS | 1);
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x += sc606_i2c_getack();
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@ -181,6 +199,8 @@ int sc606_read(unsigned char reg, unsigned char* data)
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return x;
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}
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void sc606_init(void)
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{
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volatile int i;
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@ -194,11 +214,12 @@ void sc606_init(void)
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/* About 400us - needs 350us */
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for (i = 200; i; i--)
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DELAY(DELAY_LO);
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{
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DELAY_LO;
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}
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/* Set GPH9 (SDA) and GPH10 (SCL) to 1 */
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GPHUP &= ~(3<<9);
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SCL_HI_IN;
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SDA_HI_IN;
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GPHCON = (GPHCON & ~(0xF<<18)) | 5<<18;
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}
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