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jecottrell
Joined: 16 Jan 2005 Posts: 559 Location: Tucson, AZ
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OT: FTDI/PIC Interface Question |
Posted: Thu Nov 30, 2006 2:29 pm |
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I apologize in advance for the OT question, but it looks like there's a fair number of FTDI users amongst you.
The example circuit that FTDI shows (p.26 of http://www.ftdichip.com/Documents/DataSheets/DS_FT232R_v104.pdf) for interfacing their FT232R part with an MCU has a 12MHz output from the FTDI part clocking the MCU. That's not required is it? I would assume that everything would be OK if the PIC and the FTDI part were both set to the same BAUD and the PIC had its own oscillator?
I take it the FTDI clocking of the MCU is a way to reduce parts count for a homogeneous application (i.e. the MCU and the FTDI work together) as opposed to just using the FTDI as a peripheral...
Thanks,
John |
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kender
Joined: 09 Aug 2004 Posts: 768 Location: Silicon Valley
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Re: OT: FTDI/PIC Interface Question |
Posted: Thu Nov 30, 2006 4:00 pm |
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jecottrell wrote: | I would assume that everything would be OK if the PIC and the FTDI part were both set to the same BAUD and the PIC had its own oscillator? |
I think, you're right on this one.
I haven't used the new FTDI chip with onboard oscillator and EEPROM, but the previous generation of FTDI USB-to-UART chips didn't require the PIC and FTDI to run off the same clock. |
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jecottrell
Joined: 16 Jan 2005 Posts: 559 Location: Tucson, AZ
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Posted: Thu Nov 30, 2006 4:07 pm |
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Nick,
Thanks, that jogged my memory. Now I recall from my reading that was one of the added features of the new chip. The on-chip oscillator eliminated the need for another oscillator for the FTDI part. I went back and looked at the old design guide and it confirms our suspicions.
John |
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Neutone
Joined: 08 Sep 2003 Posts: 839 Location: Houston
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Posted: Thu Nov 30, 2006 11:59 pm |
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You don't need an oscillator in your circuit except the on in the FTDI part. The FTDI part can also create 6, 24 and 48MHz clock outputs. Add to that the FTDI part can use basically any BAUD rate. |
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