Output on a bit condition

Alessandro · 2008-09-19 16:14

Hi again!

I'm making a sort of polling and i have to make a pin high if a bit of a variable is 1 or i have to make the same pin low if the bit of a varialbe is 0.

bytetest····· var byte
dataout······ var rb.0

.....
dataout=bytetest.7· (the MSB of bytetest)

but it seems to not work...

i have also use "IF"·
If bytetest.7=1 then high dataout··· (it doesn't work the same)

it is a stupid .... but i'm going crazy.

Can anybody help me?
Alessandro (italy)

JonnyMac · 2008-09-19 16:51

You should use the PIN definition for your output -- like this:

DataOut         PIN     RB.0 OUTPUT

... then it will follow the selected bit of your test byte. You didn't post the whole program so I'm guessing that RB.0 was not made an output hence you were not able to see anything (externally) that was written to the RB.0 output register.

Alessandro · 2008-09-19 21:33

On monday i will try your guess....

i was able to see if i wrote "high DataOut" with this i read a 1 on my oscilloscope.

Thanks....
you are GREAT!

Alessandro

JonnyMac · 2008-09-19 22:43

It's not a guess, it actually works!

Here you can see it in use in one of my programs that writes a byte to an ISD17xx chip while reading a byte back.

' Use: bResult = SHIFT_IO aByte
' -- sends 'aByte' on MOSI
' -- receives 'bResult' on MISO

FUNC SHIFT_IO
  tmpB1 = __PARAM1                              ' capture MOSI byte
  tmpB2 = 0                                     ' clear MISO byte

  FOR tmpB3 = 0 TO 7
    SClk = 0                                    ' SClk: 1 -> 0
    MoSi = tmpB1.0                              ' setup MOSI bit
    tmpB1 = tmpB1 >> 1                          ' prep for next bit
    DELAY_US 1
    tmpB2 = tmpB2 >> 1                          ' prep for new bit
    tmpB2.7 = MiSo                              ' get it
    SClk = 1                                    ' SClk: 0 -> 1
    DELAY_US 1
  NEXT
  RETURN tmpB2
  ENDFUNC

Alessandro · 2008-09-22 09:48

This is my code... but it is not working....

I'm doing a polling on a bit and when i read an external clock i have to make an output...

the comments are in italian, but if you need i can traslate.

it is not the complete program but i have to debug in small piece...

' =========================================================================
'
'·· File...... TEMPLATE.SXB
'·· Purpose... SX/B Programming Template
'·· Author....·
'·· E-mail....·
'·· Started...
'·· Updated...
'
' =========================================================================

'

' Program Description
'

'

' Device Settings
'

DEVICE········· SX28, OSC4MHZ, TURBO, STACKX, OPTIONX
FREQ··········· 4_000_000

'

' IO Pins
'

'

waitbit··var ·rc.0
ackbit··var·rc.1
data_inout·pin·rc.6
clock_in·pin·rc.7

Rx1byte··var ·byte

' =========================================================================
· PROGRAM Start
' =========================================================================

Start:

Rx1byte=%10000000

watch Rx1byte
Main:
· high waitbit·'dico alla Bs2 che i dati sono pronti
pauseus 100
·low waitbit
attesa_invio1_clk_alto:
if ackbit=0 then goto attesa_invio1_clk_alto·'aspetto il bit di conferma di inizio ricezione

attesa_invio1_clk_alto7:
if clock_in=0 then goto attesa_invio1_clk_alto7

'high data_inout···· <

this instead works fine... but i don't need a static output
data_inout=Rx1byte.7 <

it in particolar doesn't work even with "pin" definition

attesa_invio1_clk_basso7:
if clock_in=1 then goto attesa_invio1_clk_basso7
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
attesa_invio1_clk_alto6:
if clock_in=0 then goto attesa_invio1_clk_alto6
data_inout=1

attesa_invio1_clk_basso6:
if clock_in=1 then goto attesa_invio1_clk_basso6
break

Thanks
Alessandro (italy)

JonnyMac · 2008-09-22 10:59

I don't know what you're doing but your program compiles fine for me using the PIN definition as you should (with the OUTPUT option -- refer to my earlier response). Are you using version 1.51.03 of the compiler?

Output on a bit condition

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