How do I poll the register of another device?

Printable View

- 14th December 2008, 22:46
dbachman

How do I poll the register of another device?

The datasheet of the MT8888 DTMF transceiver says to read the status register and if bit one is set, do the next step. The datasheet says to send b7, b6 and b5 as %110. Do I make portb = %11000000? On the next statement do I say "If portb.1 = 1 then next step"? I'm kind of stuck and any enlightenment would sure help.

Thanks, Don

While thinking about it more, Can I send %11000000 on portb, then "Trisb = $1111111" then do the If Then statement to check if b1 is set?
- 15th December 2008, 05:29
skimask

Quote:

Originally Posted by dbachman

The datasheet of the MT8888 DTMF transceiver says to read the status register and if bit one is set, do the next step. The datasheet says to send b7, b6 and b5 as %110. Do I make portb = %11000000? On the next statement do I say "If portb.1 = 1 then next step"? I'm kind of stuck and any enlightenment would sure help.

Not seeing any reference to b7,b6,b5 in the datasheet (MT8888C from Mitel/Zarlink) or a couple of other datasheets.
Which datasheet are you using?
- 15th December 2008, 14:22
dbachman

Hi Skimask,

On Page 4-101, the typical control sequence for burst mode applications:

I have wired RSO as portb.7, WR as portb.6 and RD as portb.5.

When I send one of those sequences such as 'Write to transmit data register'
I send %00100111 where I have called RSO -b7(or bit7), WR - b6(or bit6) and RD- b5(or bit5) - portb.5 (b5) is not wired and b3-b0 (bit3 - bit0) is the data.

I hope this makes sense to you.

Thanks, Don
- 15th December 2008, 14:58
dbachman

Quote:

I have wired RSO as portb.7, WR as portb.6 and RD as portb.5.

- portb.5 (b5) is not wired and b3-b0 (bit3 - bit0) is the data.

The above sould have said:

I have wired RSO as portb.7, WR as portb.6 and RD as portb.5.

- portb.4 (b4) is not wired and b3-b0 (bit3 - bit0) is the data.

I hope this makes sense to you.

Thanks, Don
- 15th December 2008, 20:23
skimask

Quote:

Originally Posted by dbachman

The above sould have said:
I have wired RSO as portb.7, WR as portb.6 and RD as portb.5.
- portb.4 (b4) is not wired and b3-b0 (bit3 - bit0) is the data.
I hope this makes sense to you.
Thanks, Don

Yep, that makes sense now.
More later when I hit the datasheet a bit more...

You got any code to work with yet? Show it...
- 16th December 2008, 01:34
dbachman

This is what I have been trying:

Code:

OSCCON = $60 ' Set up internal oscillator x var byte dtmf var byte CS var portb.4 'Enable or disable MT8888 RD var portb.5 'Read Microprocessor input WR var portb.6 'Write Microprocessor input RS var portb.7 'Register Select Send_DTMF: TRISB = %00000000 pause 100 portb = %10101101 'Send Control Register A pause 100 portb = %10100000 'Send Control Register B pause 100 portb = %00100111 'Send digit = 7 pause 100 portb = %00100101 ' Send digit = 5 pause 100 Goto Send_DTMF

I should mention that this part of the code is just trying to get the thing to spit out a DTMF tone. Beyond that I would need to poll the status register.

Thanks for taking the time to help,

Don