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Reverted to the old ADC driver, since it appeared to cause fake OFF keypresses (weird indeed, since the OFF key doesn't use the ADC on the plain Recorder). However, I did fix the batch convert, since it caused fake keypresses at boot time.

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@4260 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Linus Nielsen Feltzing 2004-01-20 11:57:50 +00:00
parent 14971f49cd
commit 26f42605c2
1 changed files with 48 additions and 37 deletions
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85
firmware/drivers/adc.c
View file

@ -22,38 +22,25 @@
#include "thread.h"
#include "adc.h"
/* This driver updates the adcdata[] array by converting one A/D channel
group on each system tick. Each group is 4 channels, which means that
it takes 2 ticks to convert all 8 channels. */
static int current_group;
static int current_channel;
static unsigned short adcdata[NUM_ADC_CHANNELS];
static unsigned int adcreg[NUM_ADC_CHANNELS] =
{
ADDRAH_ADDR, ADDRBH_ADDR, ADDRCH_ADDR, ADDRDH_ADDR,
ADDRAH_ADDR, ADDRBH_ADDR, ADDRCH_ADDR, ADDRDH_ADDR
};
static void adc_tick(void)
{
/* Copy the data from the previous conversion */
if(current_group)
{
adcdata[4] = ADDRA >> 6;
adcdata[5] = ADDRB >> 6;
adcdata[6] = ADDRC >> 6;
adcdata[7] = ADDRD >> 6;
}
else
{
adcdata[0] = ADDRA >> 6;
adcdata[1] = ADDRB >> 6;
adcdata[2] = ADDRC >> 6;
adcdata[3] = ADDRD >> 6;
}
/* Read the data that has bee converted since the last tick */
adcdata[current_channel] =
*(unsigned short *)adcreg[current_channel] >> 6;
/* Start converting the next group */
current_group = !current_group;
ADCSR = ADCSR_ADST | ADCSR_SCAN | (current_group?4:0) | 3;
/* The conversion will be ready when we serve the next tick interrupt.
No need to check ADCSR for finished conversion since the conversion
will be ready long before the next tick. */
/* Start a conversion on the next channel */
current_channel++;
if(current_channel == NUM_ADC_CHANNELS)
current_channel = 0;
ADCSR = ADCSR_ADST | current_channel;
}
unsigned short adc_read(int channel)
@ -61,20 +48,44 @@ unsigned short adc_read(int channel)
return adcdata[channel];
}
void adc_init(void)
/* Batch convert 4 analog channels. If lower is true, convert AN0-AN3,
* otherwise AN4-AN7.
*/
static void adc_batch_convert(bool lower)
{
ADCR = 0x7f; /* No external trigger; other bits should be 1 according
to the manual... */
int reg = lower ? 0 : 4;
volatile unsigned short* ANx = ((unsigned short*) ADDRAH_ADDR);
int i;
/* Make sure that there is no conversion running */
ADCSR = ADCSR_ADST | ADCSR_SCAN | reg | 3;
/* Busy wait until conversion is complete. A bit ugly perhaps, but
* we should only need to wait about 4 * 14 µs */
while(!(ADCSR & ADCSR_ADF))
{
}
/* Stop scanning */
ADCSR = 0;
/* Start with converting group 0 by setting current_group to 1 */
current_group = 1;
for (i = 0; i < 4; i++)
{
/* Read converted values */
adcdata[reg++] = ANx[i] >> 6;
}
}
void adc_init(void)
{
ADCR = 0x7f; /* No external trigger; other bits should be 1 according to the manual... */
current_channel = 0;
/* Do a first scan to initialize all values */
/* AN4 to AN7 */
adc_batch_convert(false);
/* AN0 to AN3 */
adc_batch_convert(true);
tick_add_task(adc_tick);
/* Wait until both groups have been converted before we continue,
so adcdata[] contains valid data */
sleep(2);
}