Usermanual for MSP430 Robot Booster Pack (Robot Shield V1.0)
Robot shield is a booster pack designed for MSP430 Launchpad (MSP-EXP430G2).You an use it to learn about Motor control ,RS485 communication,Robotics etc.
Connecting the Booster Pack
Plug the Booster pack in such a way that connector P4 (RS485 Screw terminal) is directly above the USB connector of the Launchpad development board as shown in the below figure.
Power supply for the Motor along with the board and MSP430 controller are taken from the connector P2.You can connect anything from 8V to 15V to Connector P2.Please observe correct polarities while connecting Power supply to P2.
The voltage regulators in the RobotShield will convert the input voltage into 5V and 3.3V required by the RobotShield board and MSP430.The motors connected to the board are driven at the input voltage given to P2.For eg if you are providing 12V to P2, the two motors Connected to MOTOR_L and MOTOR_R connector will be driven at 12V.
Motor Controller Section
The Motor controller section is build around the popular L293D Quadruple Half H driver chip which can be used to provide bidirectional control for two DC brushed motors.The L293D is designed to provide bidirectional drive currents of up to 600-mA at voltages from 4.5 V to 15 V. Both devices are designed to drive inductive loads such as relays, solenoids,motors etc.The Motor Driver Section of the Robot Shield is enclosed within the red lines in the below figure.The circuit of the shield can be downloaded from here.
The two screw terminal connectors on the right side of the board designated as MOTOR_R and MOTOR_L are used for connecting the motors that you wish to control.
The LED's designated as A1 (D9) and A2 (D10) on the left side of L293D shows the status of 1A and 2A pins of L293D which controls the MOTOR_R connector while the LED's designated as B1 (D11) and B2 (D12) on the right side of L293D shows the status of 3A and 4A pins of L293D which controls the MOTOR_L connector (below figure).
The LED's designated as RIGHT (D6) is connected to pin 1 of L293D (1&2_EN) which is used to enable MOTOR_R terminal pairs (1Y and 2Y).The LED's designated as LEFT (D7) is connected to pin 9 of L293D (3&4_EN) which is used to enable MOTOR_L terminal pairs (3Y and 4Y).Simplified circuit is shown below.
The motor control chip L293D is interfaced to MSP430 launchpad board through connectors P3 and P5 as shown in the below figure.
The RS485 section of the booster pack is build around MAX485 chip from Maxim.The RS485 section can be used for building long distance communication links ,communicating with distant sensors,enabling wired control of unmanned vehicles or robots.
The TXD and RXD pins of MSP430 in the launchpad board is connected to the DI and RO pins of MAX485 through the jumper P1 as shown in the above figure.The ~RE and DE pins of MAX485 are connected to P2.5 and P1.7 pins of MSP430.The LED's D3 and D4 are used to indicate the status of ~RE and DE pins of MAX485.The A and B outputs of MAX485 are brought out through terminal block connector P4.
The Full circuit of the booster pack can be downloaded from here.
The rest of the unused pins are brought outside to connector P13