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Discussion Groups | Rabbit-Semi | Rabbit 2000 Serial Port A and B, for SPI device interface
This is a group for folks designing and programming embedded systems using the Rabbit Semiconductor C-programmable microcontroller. Rabbit Semi is a spin-off from Z-World who makes a variety of embedded modules and tools. This group is not affiliated with either Rabbit or Z-World, but is a user forum for sharing ideas, asking questions, flaunting knowledge, and other typical user group stuff. The Rabbit is a powerful uC, supported by a full-featured C-compiler.
Rabbit 2000 Serial Port A and B, for SPI device interface - kshi1028 - Apr 29 14:28:47 2008
Hi, one of my company's product uses Rabbit 2000 on the CPU board and
Dynamic C version 7.25 is used. On the hardware, Rabbit 2000 chip's
serial port B (PB0 (CLKB) and Parallel Port C, PC4&PC5) is used to
support a major feature via SPI (clocked serial mode??). Now the
board needs to interface with a new SPI driven device (using PB1
(CLKA), Parallel Port C's PC6&PC7). Since on Rabbit 2000 chips, only
serial port A and B have the capablity of being able to operate as
clocked serial ports. The hardware engineer in my company suggested
to use serial port A to support the new SPI device since it is only
being used as flash programmer. So it is available during the normal
operation of the system.
My questions are:
1) I noticed from some online information (such as Rabbit TN200) that
serial port A should not be used for SPI unless absolute necessary, I
wonder why. Would it cause any potential problem on hardware or
software if did so???
2) On Rabbit 2000 Microprocessor User's Manual, section 2.2.1, Serial
Ports, it pointed out that serial port A and B can be operated
ALTERNATELY in the clocked serial mode. What is it mean? Does it mean
that only one serial port, either A or B can be functioned as the
clocked serial mode at one time?
Very appreciate for your help!
Karen Shi
------------------------------------
(You need to be a member of rabbit-semi -- send a blank email to rabbit-semi-subscribe@yahoogroups.com )
Dynamic C version 7.25 is used. On the hardware, Rabbit 2000 chip's
serial port B (PB0 (CLKB) and Parallel Port C, PC4&PC5) is used to
support a major feature via SPI (clocked serial mode??). Now the
board needs to interface with a new SPI driven device (using PB1
(CLKA), Parallel Port C's PC6&PC7). Since on Rabbit 2000 chips, only
serial port A and B have the capablity of being able to operate as
clocked serial ports. The hardware engineer in my company suggested
to use serial port A to support the new SPI device since it is only
being used as flash programmer. So it is available during the normal
operation of the system.
My questions are:
1) I noticed from some online information (such as Rabbit TN200) that
serial port A should not be used for SPI unless absolute necessary, I
wonder why. Would it cause any potential problem on hardware or
software if did so???
2) On Rabbit 2000 Microprocessor User's Manual, section 2.2.1, Serial
Ports, it pointed out that serial port A and B can be operated
ALTERNATELY in the clocked serial mode. What is it mean? Does it mean
that only one serial port, either A or B can be functioned as the
clocked serial mode at one time?
Very appreciate for your help!
Karen Shi
------------------------------------
(You need to be a member of rabbit-semi -- send a blank email to rabbit-semi-subscribe@yahoogroups.com )
Re: Rabbit 2000 Serial Port A and B, for SPI device interface - Scott Henion - Apr 29 16:11:45 2008
kshi1028 wrote:
> Hi, one of my company's product uses Rabbit 2000 on the CPU board and
> Dynamic C version 7.25 is used. On the hardware, Rabbit 2000 chip's
> serial port B (PB0 (CLKB) and Parallel Port C, PC4&PC5) is used to
> support a major feature via SPI (clocked serial mode??). Now the
> board needs to interface with a new SPI driven device (using PB1
> (CLKA), Parallel Port C's PC6&PC7). Since on Rabbit 2000 chips, only
> serial port A and B have the capablity of being able to operate as
> clocked serial ports. The hardware engineer in my company suggested
> to use serial port A to support the new SPI device since it is only
> being used as flash programmer. So it is available during the normal
> operation of the system.
>
> My questions are:
> 1) I noticed from some online information (such as Rabbit TN200) that
> serial port A should not be used for SPI unless absolute necessary, I
> wonder why. Would it cause any potential problem on hardware or
> software if did so???
>
You need to still have it available to program the boards or debug.
> 2) On Rabbit 2000 Microprocessor User's Manual, section 2.2.1, Serial
> Ports, it pointed out that serial port A and B can be operated
> ALTERNATELY in the clocked serial mode. What is it mean? Does it mean
> that only one serial port, either A or B can be functioned as the
> clocked serial mode at one time?
>
Both can be used as synchronous or asynchronous ports.
If you are going to use port A, use the alternate TX/RX pins on port D.
That will prevent interference with the programming port (and on some
modules, the port A TX/RX pins are not on the main header.
Dynamic C may not support 2 serial ports in clocked mode if both require
SPI.lib.
Why not add the device to the existing SPI port? Just use a different
chip select pin.
--
------------------------------------------
| Scott G. Henion| s...@shdesigns.org |
| Consultant | Stone Mountain, GA |
| SHDesigns http://www.shdesigns.org |
------------------------------------------
Rabbit libs: http://www.shdesigns.org/rabbit/
today's fortune
The greatest and most important problems of life cannot be solved.
They can only be outgrown.
-- SISTER JESSICA, private journal entry
------------------------------------
(You need to be a member of rabbit-semi -- send a blank email to rabbit-semi-subscribe@yahoogroups.com )
> Hi, one of my company's product uses Rabbit 2000 on the CPU board and
> Dynamic C version 7.25 is used. On the hardware, Rabbit 2000 chip's
> serial port B (PB0 (CLKB) and Parallel Port C, PC4&PC5) is used to
> support a major feature via SPI (clocked serial mode??). Now the
> board needs to interface with a new SPI driven device (using PB1
> (CLKA), Parallel Port C's PC6&PC7). Since on Rabbit 2000 chips, only
> serial port A and B have the capablity of being able to operate as
> clocked serial ports. The hardware engineer in my company suggested
> to use serial port A to support the new SPI device since it is only
> being used as flash programmer. So it is available during the normal
> operation of the system.
>
> My questions are:
> 1) I noticed from some online information (such as Rabbit TN200) that
> serial port A should not be used for SPI unless absolute necessary, I
> wonder why. Would it cause any potential problem on hardware or
> software if did so???
>
You need to still have it available to program the boards or debug.
> 2) On Rabbit 2000 Microprocessor User's Manual, section 2.2.1, Serial
> Ports, it pointed out that serial port A and B can be operated
> ALTERNATELY in the clocked serial mode. What is it mean? Does it mean
> that only one serial port, either A or B can be functioned as the
> clocked serial mode at one time?
>
Both can be used as synchronous or asynchronous ports.
If you are going to use port A, use the alternate TX/RX pins on port D.
That will prevent interference with the programming port (and on some
modules, the port A TX/RX pins are not on the main header.
Dynamic C may not support 2 serial ports in clocked mode if both require
SPI.lib.
Why not add the device to the existing SPI port? Just use a different
chip select pin.
--
------------------------------------------
| Scott G. Henion| s...@shdesigns.org |
| Consultant | Stone Mountain, GA |
| SHDesigns http://www.shdesigns.org |
------------------------------------------
Rabbit libs: http://www.shdesigns.org/rabbit/
today's fortune
The greatest and most important problems of life cannot be solved.
They can only be outgrown.
-- SISTER JESSICA, private journal entry
------------------------------------
(You need to be a member of rabbit-semi -- send a blank email to rabbit-semi-subscribe@yahoogroups.com )