Re: Faster LIN or simpler CAN or ...? PIC16 or Cypress FX2LP or ...?

Bill Davy wrote:
To support various modules inside a machine. The likely architecture is a front end PC talking USB 2.0 to a Cypress FX2LP in the machine. That then splits the control work out to various nodes (spinner, motor, shutter, laser, etc), connected by a bus.



a) CAN involves me in checking each message was received once and only once. There's not a lot of space in the Cypress for that sort of thing.



b) We could use LIN but it seems jolly slow. Would mean a nice simple processor in each node with a little programming and offering some flexibility.



c) We could use a modified form of I2C but that means no intelligence at each node (and no programming, which is quite a good thing, in some ways).



Can I do LIN master in the Cypress FX2 (8051 based with a couple of UART's)?

Is there a reasonably standard way for doing LIN slave? I'd prefer 8051 based (so I can go on using the Keil compiler) or PIC16 (which we have also used).

Any other thoughts (but not too innovative - this is a development project)?

Look into the 80C51 9 Bit mode : that sits between CAN and LIN in speed, and is simpler than LIN to code, as you use the inbuilt HW support.

You can use CAN transceivers, on a 9 Bit UART datastream.

i2c has the poorest noise immunity.

LIN has high immunity, because it is large swing, and slow.
LIN has very small payloads, and is really for the last-link usage.

CAN is multimaster, and has CRC included, whilst 9 Bit mode is single master, but can use much lower cost silicon.
80C51's with UARTS start well under $1, and in tiny packages, and
support data rates higher than CAN.

-jg



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Relevant Pages

  • Faster LIN or simpler CAN or ...? PIC16 or Cypress FX2LP or ...?
    ... front end PC talking USB 2.0 to a Cypress FX2LP in the machine. ... There's not a lot of space in the Cypress for that sort of thing. ... each node (and no programming, which is quite a good thing, in some ways). ... Can I do LIN master in the Cypress FX2? ...
    (comp.arch.embedded)
  • Re: Faster LIN or simpler CAN or ...? PIC16 or Cypress FX2LP or ...?
    ... The likely architecture is a ... There's not a lot of space in the Cypress for that sort of thing. ... > b) We could use LIN but it seems jolly slow. ... > each node (and no programming, which is quite a good thing, in some ways). ...
    (comp.arch.embedded)