Author: sebastien.lelong
Date: Sun Jun 7 10:36:05 2009
New Revision: 1036
Modified:
trunk/include/peripheral/adc/adc.jal
trunk/include/peripheral/adc/adc_clock.jal
trunk/sample/16f88_adc_lowres.jal
Log:
fix 2*tad delay, convert test
Modified: trunk/include/peripheral/adc/adc.jal
==============================================================================
--- trunk/include/peripheral/adc/adc.jal (original)
+++ trunk/include/peripheral/adc/adc.jal Sun Jun 7 10:36:05 2009
@@ -58,14 +58,10 @@
-- Does an AD conversion with low resolution (8 bit) on the selected
channel
procedure _adc_read_low_res(byte in adc_chan, byte out adc_byte) is
- if target_chip == PIC_12F675 then
- ADCON0 = _adcon0_shadow | ((adc_chan & 0x03) << 2) -- setup
multiplexer
- else
- ADCON0 = _adcon0_shadow | ((adc_chan & 0x07) << 3) -- setup
multiplexer
- end if
+ ADCON0_CHS = adc_chan
delay_10us(adc_conversion_delay) -- wait acquisition time
- ADCON0_GO = true -- start conversion
- while ADCON0_GO loop end loop -- wait till conversion
finished
+ ADCON0_GO = true -- start conversion
+ while ADCON0_GO loop end loop -- wait till conversion finished
-- 2 cases:
-- - PIC has 10-bits ADC: since low resoltion if left
-- justified, need to read ADRESH
@@ -77,11 +73,14 @@
else
adc_byte = ADRES
end if
- if target_clock <= (5_000_000 / 16) then
- delay_10us(1) -- to satisfy 2*Tad for next
conversion
+ -- Honor 2*Tad time
+ -- tad_value comes from adc_clock
+ -- we won't be that accurate here (mostly because there's no
delay_usec(byte in x) procedure)
+ if tad_value >= (ADC_MAX_TAD + ADC_MIN_TAD) / 2 then
+ _usec_delay(2 * ADC_MAX_TAD)
+ else
+ _usec_delay(2 * ADC_MIN_TAD)
end if
- -- Seb: but what if target_clock is, say 8MHz ? There's no 2*Tad delay.
Is it because
- -- was "too" generous when computing _adc_acquisition_time ?
end procedure
@@ -93,10 +92,10 @@
var byte ax[2] at ad_value
if ADC_HIGH_RESOLUTION then
- _adc_read_low_res (adc_chan,ax[1]) -- do conversion and get high
byte
+ _adc_read_low_res(adc_chan,ax[1]) -- do conversion and get high
byte
ax[0] = ADRESL -- get low byte
else
- _adc_read_low_res (adc_chan,ax[0]) -- do conversion and get low
byte
+ _adc_read_low_res(adc_chan,ax[0]) -- do conversion and get low byte
ax[1] = 0 -- clear high byte
-- shift 2 highest order bits form low byte to high byte,
-- to get a 10-bit result
@@ -113,7 +112,7 @@
procedure adc_read_bytes(byte in adc_chan, byte out adc_hbyte, byte out
adc_lbyte) is
var word ad_value
var byte ax[2] at ad_value
- ad_value = adc_read (adc_chan)
+ ad_value = adc_read(adc_chan)
adc_hbyte = ax[1]
adc_lbyte = ax[0]
end procedure
@@ -130,10 +129,14 @@
_adc_read_low_res(adc_chan,adc_hbyte)
adc_value = ADRESL
-- shift the 2 highest order bits form high byte to low byte
- asm rrf adc_hbyte,f
- asm rrf adc_value,f
- asm rrf adc_hbyte,f
- asm rrf adc_value,f
+ adc_hbyte = adc_hbyte >> 1
+ adc_value = adc_value >> 1
+ adc_hbyte = adc_hbyte >> 1
+ adc_value = adc_value >> 1
+ ;;asm rrf adc_hbyte,f
+ ;;asm rrf adc_value,f
+ ;;asm rrf adc_hbyte,f
+ ;;asm rrf adc_value,f
end if
return adc_value
end function
Modified: trunk/include/peripheral/adc/adc_clock.jal
==============================================================================
--- trunk/include/peripheral/adc/adc_clock.jal (original)
+++ trunk/include/peripheral/adc/adc_clock.jal Sun Jun 7 10:36:05 2009
@@ -15,6 +15,8 @@
-- See adc_init for details
+var byte tad_value
+
if defined(ADC_MIN_TAD) == false then
-- So this is 1.6usecs
const byte ADC_MIN_TAD = 16
@@ -36,10 +38,8 @@
-- So, byte * 10 will give a byte. Ex: 32 * 10 = 64 ...
-- That's we use a word, so the result can fit in a word (320)
- var word tad_value = 0
var bit tad_ok = false
- tad_value = (factor * 10) / (target_clock / 1_000_000)
- test_word(tad_value)
+ tad_value = byte((factor * 10) / (target_clock / 1_000_000))
if tad_value >= ADC_MIN_TAD & tad_value < ADC_MAX_TAD then
tad_ok = true
end if
Modified: trunk/sample/16f88_adc_lowres.jal
==============================================================================
--- trunk/sample/16f88_adc_lowres.jal (original)
+++ trunk/sample/16f88_adc_lowres.jal Sun Jun 7 10:36:05 2009
@@ -58,21 +58,21 @@
serial_hw_write("!")
-- Configure ADC
--- We just need only one ADC channel
-const adc_hardware_nchan = 1
-- We won't use any external VRef, so measures are done
-- according to PIC powering voltage
-const adc_hardware_nvref = 0
+const byte ADC_NVREF = 0
-- The maximum resistance while measuring ADC is... (unit: ohms)
-- Being accurate helps speeding up ADC acquisition
-const adc_hardware_rsource = 2_000
+const word ADC_RSOURCE = 2_000
-- In this example, we'll perform low resolution ADC: results are
-- coded on 8bits
-const adc_hardware_high_resolution = false
+const bit ADC_HIGH_RESOLUTION = false
-- Now include the famous library
-include adc_hardware
+include adc
-- And initialize the whole with our parameters
adc_init()
+-- We just need only one ADC channel
+set_analog_pin(0) -- make RA0/AN0 analog
-- will periodically send those chars
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