SPI communication between two dsPIC - Revision history

LubinKerhuel: /* Electronics */

2011-02-15T01:01:58Z

Electronics

LubinKerhuel at 01:00, 15 February 2011

2011-02-15T01:00:25Z

LubinKerhuel: /* Model A: Emission */

2011-02-15T00:07:18Z

Model A: Emission

LubinKerhuel: /* Electronics */

2011-02-15T00:06:07Z

Electronics

LubinKerhuel at 00:05, 15 February 2011

2011-02-15T00:05:33Z

LubinKerhuel at 00:02, 15 February 2011

2011-02-15T00:02:14Z

LubinKerhuel at 00:11, 5 January 2011

2011-01-05T00:11:58Z

LubinKerhuel: Created page with "=Description= The objective of this example is to demonstrate how to use a SPI bus to transmit data between two microcontrollers. Two dsPIC (30f3012) exchanges numerical values..."

2010-12-30T22:41:17Z

Created page with "=Description= The objective of this example is to demonstrate how to use a SPI bus to transmit data between two microcontrollers. Two dsPIC (30f3012) exchanges numerical values..."

New page

=Description=

The objective of this example is to demonstrate how to use a SPI bus to transmit data between two microcontrollers. Two dsPIC (30f3012) exchanges numerical values through a SPI bus. Both dsPIC are programmed using blocks from the dsPIC blockset for simulink available on this website. This example was added in the blockset version 3.4.

Next to come...

@@ Line 30: / Line 30: @@
 =Electronics=
 We use the same prototyping board described in the [[PWM_communication_between_two_dsPIC#Electronics|PWM example]]. And a bootloader capable of flashing the binary into the chip through UART is also used as it is described [[PWM_communication_between_two_dsPIC#Bootloader|here]].
 The PWM wire is removed.
-[[Image:SPI_addedComponents.jpg|thumb|left|85px|1 capacity added on the SPI clock input pin of the slave microcontroller]]
 Data are sent from A ==> B but no data are sent from B ==> A. Thus only one data wire is required here. The SS pin (that is the SPI chip select when configured as slave) is not workable on the dsPIC 30f4012. The SPI slave peripheral is always enabled. Thus, the CS wire is not required also. Thus only two wires are necessary : The Clk for the Clock. The SDO (output) pin of A is connected to the SDI (input) of B. .

@@ Line 34: / Line 34: @@
 The PWM wire is removed.
 Data are sent from A ==> B but no data are sent from B ==> A. Thus only one data wire is required here. The SS pin (that is the SPI chip select when configured as slave) is not workable on the dsPIC 30f4012. The SPI slave peripheral is always enabled. Thus, the CS wire is not required also. Thus only two wires are necessary : The Clk for the Clock. The SDO (output) pin of A is connected to the SDI (input) of B. .
@@ Line 47: / Line 48: @@
 Optimized method for sine wave generation was described in the [[PWM_communication_between_two_dsPIC#Sine wave generation|PWM example]].
-Execution time is 2.25% of a time step
+Execution time use 2.25% of a time step.
 ===SPI BUS write===

@@ Line 47: / Line 47: @@
 Optimized method for sine wave generation was described in the [[PWM_communication_between_two_dsPIC#Sine wave generation|PWM example]].
 ===SPI BUS write===
-−
 ==Model B: Reception==
 [[Image:SimulinkModel_SPI_b_30f4012.png|thumb|right|350px|Simulink model B: SPI_b_30f4012]]
 [[Image:rs232gui_SPI_b_ReceivedValue.png|thumb|none|350px|Matlab plot of the data sent by microcontroller B through UART. The rs232gui interface is used to plot incoming data in real-time]]

@@ Line 30: / Line 30: @@
 =Electronics=
-We use the same prototyping board described in the [[PWM_communication_between_two_dsPIC#Electronics|PWM example]]. And a bootloader capable of flashing the binary into the chip through UART is also used as it is described [[PWM_communication_between_two_dsPIC#Bootloader|here].
+We use the same prototyping board described in the [[PWM_communication_between_two_dsPIC#Electronics|PWM example]]. And a bootloader capable of flashing the binary into the chip through UART is also used as it is described [[PWM_communication_between_two_dsPIC#Bootloader|here]].
 The PWM wire is removed.
 Data are sent from A ==> B but no data are sent from B ==> A. Thus only one data wire is required here. The SS pin (that is the SPI chip select when configured as slave) is not workable on the dsPIC 30f4012. The SPI slave peripheral is always enabled. Thus, the CS wire is not required also. Thus only two wires are necessary : The Clk for the Clock. The SDO (output) pin of A is connected to the SDI (input) of B. .
-−
 =Simulink models=
 Two simulink models generate the code for the dsPIC (A) and the dsPIC (B).  The common part of theses two model has been descriped on the [[PWM_communication_between_two_dsPIC#Common parts |PWM example]].

@@ Line 45: / Line 45: @@
 The model A creates an internal sine wave signal of type int16 with amplitude 5000 and frequency 4 Hz. The sine wave generated values are transmitted to microcontroller (B) (corresponding to model B) through SPI…
-Optimized method for sine wave generation was described in the [[PWM_communication_between_two_dsPIC# Sine wave generation|PWM example]].
+Optimized method for sine wave generation was described in the [[PWM_communication_between_two_dsPIC#Sine wave generation|PWM example]].
 ===SPI BUS write===

@@ Line 1: / Line 1: @@
-[[Image:Circuit_SPI.png|thumb|right|350px|SPI Circuit]]
 =Description=
+In this example, a variable is transmitted from one microcontroller (noted A) to another (noted B) through a SPI bus. A 4Hz Sinus is generated in the (A) and sent every 1ms to the microcontroller (B) through a SPI BUS. Then, (B) send the received value to the PC through its UART peripheral. The Matlab rs232gui interface plot the received values.
-The  objective of this example is to demonstrate how to use a SPI bus to transmit data between two microcontrollers. Two dsPIC (30f3012) exchanges numerical values through a SPI bus. Both dsPIC are programmed using blocks  from the dsPIC blockset for simulink available on this website. This  example was  added in the blockset version 3.4.
+=Characteristics of SPI transmissions=
-Next to come...
+[[Image:Scope_HM205_SPI_01.jpg|thumb|right|350px|Photo of a scope showing 5 SPI trames which were sent with a 1ms interval (model time step). One trame is highlighted in yellow. The bottom part is the clock signal (Clk). The clock is active high, thus its physical level is low (0V) between trames and send 16 ticks @ 39kHz (SPI bus speed defined in SPI configuration block). The top part is the SDO pin for the emitter which sent the 16 bits data on this wire. SDO is connected to SDI pin at the receiver side which sample the data using the clock signal.]]

← Older revision		Revision as of 00:11, 5 January 2011
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		+	[[Image:Circuit_SPI.png\|thumb\|right\|350px\|SPI Circuit]]
	=Description=		=Description=